Home |
Search |
Today's Posts |
|
Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
Reply |
|
|
LinkBack | Thread Tools | Display Modes |
#1
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
Looking for input into whether this June 1996 build TV is worth having
repaired. TV has worked great since purchase in 1996. Never got a great deal of use...maybe 10 hours a week on weekends to watch mainly movies on DVD or HBO. I figure less than 4000 hours total use. Set had been on for about 4 hours one day and the picture just went blank...like someone turned it off. No warning of trouble before that...no picture fade or blooming, it just went dark. Sound still works OK. The TV is long out of warranty but due to it's light use I was thinking it might be worth repairing. Can anyone give me an idea how much would be a fair rate for a repairman to come out and diagnose (I live in Philadelphia, PA)? What's an average repair cost on a 35" set? I realize the repair costs would be on top of the initial estimate depending on what is wrong. On that note, are my TV's symptoms indicative of a common problem? Based on my novice research I think it could be a high voltage problem. The neighborhood repair guy went out of business about three years ago. Choosing a repair service, I'm finding, is almost impossible to decide on blindly. Any advice would be appreciated. Thanks |
#2
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
Could be as simple as the 110k ohm resistor that connects to the H.O.T. or a
bad flyback. You really should contact Zenith and ask for a local authorized servicer. Try www.zenith.com Good Luck, Bill Jr "Q.E.D." wrote in message ... Looking for input into whether this June 1996 build TV is worth having repaired. TV has worked great since purchase in 1996. Never got a great deal of use...maybe 10 hours a week on weekends to watch mainly movies on DVD or HBO. I figure less than 4000 hours total use. Set had been on for about 4 hours one day and the picture just went blank...like someone turned it off. No warning of trouble before that...no picture fade or blooming, it just went dark. Sound still works OK. The TV is long out of warranty but due to it's light use I was thinking it might be worth repairing. Can anyone give me an idea how much would be a fair rate for a repairman to come out and diagnose (I live in Philadelphia, PA)? What's an average repair cost on a 35" set? I realize the repair costs would be on top of the initial estimate depending on what is wrong. On that note, are my TV's symptoms indicative of a common problem? Based on my novice research I think it could be a high voltage problem. The neighborhood repair guy went out of business about three years ago. Choosing a repair service, I'm finding, is almost impossible to decide on blindly. Any advice would be appreciated. Thanks |
#3
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
im sure you all know me by now,
but I had the same problem with mine, NO HV, and i have narrowed it down to the scan gen circuits, it wasnt spitting out a waveform, not even a startup pulse. I found a scope mod that can ring check the flyback, and it checks good, so only thing left: Scan Gen IC. which the shutdown sequence is computer controlled. I NEED TO DISABLE THE SHUTDOWN TO TEST FURTHER. anyone got any insight on this? "Bill Jr" wrote in message ... Could be as simple as the 110k ohm resistor that connects to the H.O.T. or a bad flyback. You really should contact Zenith and ask for a local authorized servicer. Try www.zenith.com Good Luck, Bill Jr "Q.E.D." wrote in message ... Looking for input into whether this June 1996 build TV is worth having repaired. TV has worked great since purchase in 1996. Never got a great deal of use...maybe 10 hours a week on weekends to watch mainly movies on DVD or HBO. I figure less than 4000 hours total use. Set had been on for about 4 hours one day and the picture just went blank...like someone turned it off. No warning of trouble before that...no picture fade or blooming, it just went dark. Sound still works OK. The TV is long out of warranty but due to it's light use I was thinking it might be worth repairing. Can anyone give me an idea how much would be a fair rate for a repairman to come out and diagnose (I live in Philadelphia, PA)? What's an average repair cost on a 35" set? I realize the repair costs would be on top of the initial estimate depending on what is wrong. On that note, are my TV's symptoms indicative of a common problem? Based on my novice research I think it could be a high voltage problem. The neighborhood repair guy went out of business about three years ago. Choosing a repair service, I'm finding, is almost impossible to decide on blindly. Any advice would be appreciated. Thanks |
#4
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
Module exchange will rebuilt the main board for around 100.00 call them
http://www.tvparts.com/ "Q.E.D." wrote in message ... Looking for input into whether this June 1996 build TV is worth having repaired. TV has worked great since purchase in 1996. Never got a great deal of use...maybe 10 hours a week on weekends to watch mainly movies on DVD or HBO. I figure less than 4000 hours total use. Set had been on for about 4 hours one day and the picture just went blank...like someone turned it off. No warning of trouble before that...no picture fade or blooming, it just went dark. Sound still works OK. The TV is long out of warranty but due to it's light use I was thinking it might be worth repairing. Can anyone give me an idea how much would be a fair rate for a repairman to come out and diagnose (I live in Philadelphia, PA)? What's an average repair cost on a 35" set? I realize the repair costs would be on top of the initial estimate depending on what is wrong. On that note, are my TV's symptoms indicative of a common problem? Based on my novice research I think it could be a high voltage problem. The neighborhood repair guy went out of business about three years ago. Choosing a repair service, I'm finding, is almost impossible to decide on blindly. Any advice would be appreciated. Thanks |
#5
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
see, thats the problem. I live off of social security, and I dont have 100
dollars to put in a board. I understand the flyback is 60, but its not bad. I ring tested it. I need to disable shutdown of the scan circuity, and someone here with a schematic can tell me. "Mr. Lee" wrote in message . .. Module exchange will rebuilt the main board for around 100.00 call them http://www.tvparts.com/ "Q.E.D." wrote in message ... Looking for input into whether this June 1996 build TV is worth having repaired. TV has worked great since purchase in 1996. Never got a great deal of use...maybe 10 hours a week on weekends to watch mainly movies on DVD or HBO. I figure less than 4000 hours total use. Set had been on for about 4 hours one day and the picture just went blank...like someone turned it off. No warning of trouble before that...no picture fade or blooming, it just went dark. Sound still works OK. The TV is long out of warranty but due to it's light use I was thinking it might be worth repairing. Can anyone give me an idea how much would be a fair rate for a repairman to come out and diagnose (I live in Philadelphia, PA)? What's an average repair cost on a 35" set? I realize the repair costs would be on top of the initial estimate depending on what is wrong. On that note, are my TV's symptoms indicative of a common problem? Based on my novice research I think it could be a high voltage problem. The neighborhood repair guy went out of business about three years ago. Choosing a repair service, I'm finding, is almost impossible to decide on blindly. Any advice would be appreciated. Thanks |
#6
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
BTW, i dont have a remote for it, to get into service menu, but of course it
doesnt matter, because there is no HV, raster, or filiment. Just sound. "Mike" wrote in message ... see, thats the problem. I live off of social security, and I dont have 100 dollars to put in a board. I understand the flyback is 60, but its not bad. I ring tested it. I need to disable shutdown of the scan circuity, and someone here with a schematic can tell me. "Mr. Lee" wrote in message . .. Module exchange will rebuilt the main board for around 100.00 call them http://www.tvparts.com/ "Q.E.D." wrote in message ... Looking for input into whether this June 1996 build TV is worth having repaired. TV has worked great since purchase in 1996. Never got a great deal of use...maybe 10 hours a week on weekends to watch mainly movies on DVD or HBO. I figure less than 4000 hours total use. Set had been on for about 4 hours one day and the picture just went blank...like someone turned it off. No warning of trouble before that...no picture fade or blooming, it just went dark. Sound still works OK. The TV is long out of warranty but due to it's light use I was thinking it might be worth repairing. Can anyone give me an idea how much would be a fair rate for a repairman to come out and diagnose (I live in Philadelphia, PA)? What's an average repair cost on a 35" set? I realize the repair costs would be on top of the initial estimate depending on what is wrong. On that note, are my TV's symptoms indicative of a common problem? Based on my novice research I think it could be a high voltage problem. The neighborhood repair guy went out of business about three years ago. Choosing a repair service, I'm finding, is almost impossible to decide on blindly. Any advice would be appreciated. Thanks |
#7
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
DO NOT disable the shutdown ,are you stupid ?
Its there for the TV,s and your protection . kip I need to disable shutdown of the scan circuity, and someone here with a schematic can tell me. |
#8
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
yea im stupid, if thats the only way to find out whats wrong, because other
approatches just arnt working. like, The HOT has B+, flyback rings good, but there is NO drive signal from the scan IC for the horiz or vert. so im suspecting that the IC is either in shutdown, or is bad. there isnt even a startup pulse, and I thought that the startup pulse has to be there in order to get feedback from the flyback to shut it down. Is this true? if so, there isnt any. "john" wrote in message .. . DO NOT disable the shutdown ,are you stupid ? Its there for the TV,s and your protection . kip I need to disable shutdown of the scan circuity, and someone here with a schematic can tell me. |
#9
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
You cannot do it. Disable the xray protect in that set.
Just because the flyback ring tests ok does not mean it is good, means it does not have excessive shorted windings. Zenith flybacks are well known for having the triplers go bad, you will be able to read some resistance between the hv anode and the ground of the flyback, usually around 400K when they are bad. The 35" in that era is also well known for the shaping coil and pin cushion coils shorting out internally. There is a fuse in series with the voltage to the flyback for the main b+, without it present you also will not get any drive pulses. Mike wrote in message ... BTW, i dont have a remote for it, to get into service menu, but of course it doesnt matter, because there is no HV, raster, or filiment. Just sound. "Mike" wrote in message ... see, thats the problem. I live off of social security, and I dont have 100 dollars to put in a board. I understand the flyback is 60, but its not bad. I ring tested it. I need to disable shutdown of the scan circuity, and someone here with a schematic can tell me. "Mr. Lee" wrote in message . .. Module exchange will rebuilt the main board for around 100.00 call them http://www.tvparts.com/ "Q.E.D." wrote in message ... Looking for input into whether this June 1996 build TV is worth having repaired. TV has worked great since purchase in 1996. Never got a great deal of use...maybe 10 hours a week on weekends to watch mainly movies on DVD or HBO. I figure less than 4000 hours total use. Set had been on for about 4 hours one day and the picture just went blank...like someone turned it off. No warning of trouble before that...no picture fade or blooming, it just went dark. Sound still works OK. The TV is long out of warranty but due to it's light use I was thinking it might be worth repairing. Can anyone give me an idea how much would be a fair rate for a repairman to come out and diagnose (I live in Philadelphia, PA)? What's an average repair cost on a 35" set? I realize the repair costs would be on top of the initial estimate depending on what is wrong. On that note, are my TV's symptoms indicative of a common problem? Based on my novice research I think it could be a high voltage problem. The neighborhood repair guy went out of business about three years ago. Choosing a repair service, I'm finding, is almost impossible to decide on blindly. Any advice would be appreciated. Thanks |
#10
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
ok, I finally got to it.
All volteges are presant and none of the fuses are blown. now, there was a pin problem. Now, I set my scope up, and did some more testing on the tv, the scan gen IS working. there is a square wave pulse on the pin 8. there is a square wave pulse on the base of the horizontal driver transistor. BUT, there is NO DRIVE PULSE on the collector of the driver transistor. so, i guess its a bad transistor. I did some voltege measurements, and there is about 41VDC on the collector. There is 158VDC B+ on the HOT. I did a BtoC, and BtoE check in circuit on the transistor, and it checks OK, but i never pulled it out of circuit. Any Ideas? "Q.E.D." wrote in message ... Looking for input into whether this June 1996 build TV is worth having repaired. TV has worked great since purchase in 1996. Never got a great deal of use...maybe 10 hours a week on weekends to watch mainly movies on DVD or HBO. I figure less than 4000 hours total use. Set had been on for about 4 hours one day and the picture just went blank...like someone turned it off. No warning of trouble before that...no picture fade or blooming, it just went dark. Sound still works OK. The TV is long out of warranty but due to it's light use I was thinking it might be worth repairing. Can anyone give me an idea how much would be a fair rate for a repairman to come out and diagnose (I live in Philadelphia, PA)? What's an average repair cost on a 35" set? I realize the repair costs would be on top of the initial estimate depending on what is wrong. On that note, are my TV's symptoms indicative of a common problem? Based on my novice research I think it could be a high voltage problem. The neighborhood repair guy went out of business about three years ago. Choosing a repair service, I'm finding, is almost impossible to decide on blindly. Any advice would be appreciated. Thanks |
#11
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
P.S., the heatsink on the QX3201 stays cool.
the other 3 in the chopper circuit get regularly warm, thats the only one that stays cold. could that be something? it junction tests good. "Mike" wrote in message ... ok, I finally got to it. All volteges are presant and none of the fuses are blown. now, there was a pin problem. Now, I set my scope up, and did some more testing on the tv, the scan gen IS working. there is a square wave pulse on the pin 8. there is a square wave pulse on the base of the horizontal driver transistor. BUT, there is NO DRIVE PULSE on the collector of the driver transistor. so, i guess its a bad transistor. I did some voltege measurements, and there is about 41VDC on the collector. There is 158VDC B+ on the HOT. I did a BtoC, and BtoE check in circuit on the transistor, and it checks OK, but i never pulled it out of circuit. Any Ideas? "Q.E.D." wrote in message ... Looking for input into whether this June 1996 build TV is worth having repaired. TV has worked great since purchase in 1996. Never got a great deal of use...maybe 10 hours a week on weekends to watch mainly movies on DVD or HBO. I figure less than 4000 hours total use. Set had been on for about 4 hours one day and the picture just went blank...like someone turned it off. No warning of trouble before that...no picture fade or blooming, it just went dark. Sound still works OK. The TV is long out of warranty but due to it's light use I was thinking it might be worth repairing. Can anyone give me an idea how much would be a fair rate for a repairman to come out and diagnose (I live in Philadelphia, PA)? What's an average repair cost on a 35" set? I realize the repair costs would be on top of the initial estimate depending on what is wrong. On that note, are my TV's symptoms indicative of a common problem? Based on my novice research I think it could be a high voltage problem. The neighborhood repair guy went out of business about three years ago. Choosing a repair service, I'm finding, is almost impossible to decide on blindly. Any advice would be appreciated. Thanks |
#12
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
oh yea, one more thing, the square wave pulse is continuos, its not shutting
down, probably because its not getting to the flyback, or the base of the HOT, it dies off at the driver xistor. its there on the base, gone on the collector "Mike" wrote in message ... P.S., the heatsink on the QX3201 stays cool. the other 3 in the chopper circuit get regularly warm, thats the only one that stays cold. could that be something? it junction tests good. "Mike" wrote in message ... ok, I finally got to it. All volteges are presant and none of the fuses are blown. now, there was a pin problem. Now, I set my scope up, and did some more testing on the tv, the scan gen IS working. there is a square wave pulse on the pin 8. there is a square wave pulse on the base of the horizontal driver transistor. BUT, there is NO DRIVE PULSE on the collector of the driver transistor. so, i guess its a bad transistor. I did some voltege measurements, and there is about 41VDC on the collector. There is 158VDC B+ on the HOT. I did a BtoC, and BtoE check in circuit on the transistor, and it checks OK, but i never pulled it out of circuit. Any Ideas? "Q.E.D." wrote in message ... Looking for input into whether this June 1996 build TV is worth having repaired. TV has worked great since purchase in 1996. Never got a great deal of use...maybe 10 hours a week on weekends to watch mainly movies on DVD or HBO. I figure less than 4000 hours total use. Set had been on for about 4 hours one day and the picture just went blank...like someone turned it off. No warning of trouble before that...no picture fade or blooming, it just went dark. Sound still works OK. The TV is long out of warranty but due to it's light use I was thinking it might be worth repairing. Can anyone give me an idea how much would be a fair rate for a repairman to come out and diagnose (I live in Philadelphia, PA)? What's an average repair cost on a 35" set? I realize the repair costs would be on top of the initial estimate depending on what is wrong. On that note, are my TV's symptoms indicative of a common problem? Based on my novice research I think it could be a high voltage problem. The neighborhood repair guy went out of business about three years ago. Choosing a repair service, I'm finding, is almost impossible to decide on blindly. Any advice would be appreciated. Thanks |
#13
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
one more thing, the square wave pulse is continous, its not shutting
down, probably because its not getting to the flyback, or the base of the HOT, it dies off at the driver xistor. its there on the base, gone on the collector "Q.E.D." wrote in message ... Looking for input into whether this June 1996 build TV is worth having repaired. TV has worked great since purchase in 1996. Never got a great deal of use...maybe 10 hours a week on weekends to watch mainly movies on DVD or HBO. I figure less than 4000 hours total use. Set had been on for about 4 hours one day and the picture just went blank...like someone turned it off. No warning of trouble before that...no picture fade or blooming, it just went dark. Sound still works OK. The TV is long out of warranty but due to it's light use I was thinking it might be worth repairing. Can anyone give me an idea how much would be a fair rate for a repairman to come out and diagnose (I live in Philadelphia, PA)? What's an average repair cost on a 35" set? I realize the repair costs would be on top of the initial estimate depending on what is wrong. On that note, are my TV's symptoms indicative of a common problem? Based on my novice research I think it could be a high voltage problem. The neighborhood repair guy went out of business about three years ago. Choosing a repair service, I'm finding, is almost impossible to decide on blindly. Any advice would be appreciated. Thanks |
#14
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
IS the frequency of that square wave accurate?
IS the amplitude sufficient to turn on the horiz driver transistor? Bill Jr "Mike" wrote in message ... P.S., the heatsink on the QX3201 stays cool. the other 3 in the chopper circuit get regularly warm, thats the only one that stays cold. could that be something? it junction tests good. "Mike" wrote in message ... ok, I finally got to it. All volteges are presant and none of the fuses are blown. now, there was a pin problem. Now, I set my scope up, and did some more testing on the tv, the scan gen IS working. there is a square wave pulse on the pin 8. there is a square wave pulse on the base of the horizontal driver transistor. BUT, there is NO DRIVE PULSE on the collector of the driver transistor. so, i guess its a bad transistor. I did some voltege measurements, and there is about 41VDC on the collector. There is 158VDC B+ on the HOT. I did a BtoC, and BtoE check in circuit on the transistor, and it checks OK, but i never pulled it out of circuit. Any Ideas? "Q.E.D." wrote in message ... Looking for input into whether this June 1996 build TV is worth having repaired. TV has worked great since purchase in 1996. Never got a great deal of use...maybe 10 hours a week on weekends to watch mainly movies on DVD or HBO. I figure less than 4000 hours total use. Set had been on for about 4 hours one day and the picture just went blank...like someone turned it off. No warning of trouble before that...no picture fade or blooming, it just went dark. Sound still works OK. The TV is long out of warranty but due to it's light use I was thinking it might be worth repairing. Can anyone give me an idea how much would be a fair rate for a repairman to come out and diagnose (I live in Philadelphia, PA)? What's an average repair cost on a 35" set? I realize the repair costs would be on top of the initial estimate depending on what is wrong. On that note, are my TV's symptoms indicative of a common problem? Based on my novice research I think it could be a high voltage problem. The neighborhood repair guy went out of business about three years ago. Choosing a repair service, I'm finding, is almost impossible to decide on blindly. Any advice would be appreciated. Thanks |
#15
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
i dunno.
I just have an older scope. Its a square wave. typical old squarewave. I seen a picture of the CTC130 square wave in my tv repair handbook, it peaks out at the top of each wave, well, this one is jsut square wave. I have to put my sope on 5V to see the drops and rises. "Bill Jr" wrote in message ... IS the frequency of that square wave accurate? IS the amplitude sufficient to turn on the horiz driver transistor? Bill Jr "Mike" wrote in message ... P.S., the heatsink on the QX3201 stays cool. the other 3 in the chopper circuit get regularly warm, thats the only one that stays cold. could that be something? it junction tests good. "Mike" wrote in message ... ok, I finally got to it. All volteges are presant and none of the fuses are blown. now, there was a pin problem. Now, I set my scope up, and did some more testing on the tv, the scan gen IS working. there is a square wave pulse on the pin 8. there is a square wave pulse on the base of the horizontal driver transistor. BUT, there is NO DRIVE PULSE on the collector of the driver transistor. so, i guess its a bad transistor. I did some voltege measurements, and there is about 41VDC on the collector. There is 158VDC B+ on the HOT. I did a BtoC, and BtoE check in circuit on the transistor, and it checks OK, but i never pulled it out of circuit. Any Ideas? "Q.E.D." wrote in message ... Looking for input into whether this June 1996 build TV is worth having repaired. TV has worked great since purchase in 1996. Never got a great deal of use...maybe 10 hours a week on weekends to watch mainly movies on DVD or HBO. I figure less than 4000 hours total use. Set had been on for about 4 hours one day and the picture just went blank...like someone turned it off. No warning of trouble before that...no picture fade or blooming, it just went dark. Sound still works OK. The TV is long out of warranty but due to it's light use I was thinking it might be worth repairing. Can anyone give me an idea how much would be a fair rate for a repairman to come out and diagnose (I live in Philadelphia, PA)? What's an average repair cost on a 35" set? I realize the repair costs would be on top of the initial estimate depending on what is wrong. On that note, are my TV's symptoms indicative of a common problem? Based on my novice research I think it could be a high voltage problem. The neighborhood repair guy went out of business about three years ago. Choosing a repair service, I'm finding, is almost impossible to decide on blindly. Any advice would be appreciated. Thanks |
#16
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
and thats about right, the datasheet to the scan IC says 5vp-p
"Bill Jr" wrote in message ... IS the frequency of that square wave accurate? IS the amplitude sufficient to turn on the horiz driver transistor? Bill Jr "Mike" wrote in message ... P.S., the heatsink on the QX3201 stays cool. the other 3 in the chopper circuit get regularly warm, thats the only one that stays cold. could that be something? it junction tests good. "Mike" wrote in message ... ok, I finally got to it. All volteges are presant and none of the fuses are blown. now, there was a pin problem. Now, I set my scope up, and did some more testing on the tv, the scan gen IS working. there is a square wave pulse on the pin 8. there is a square wave pulse on the base of the horizontal driver transistor. BUT, there is NO DRIVE PULSE on the collector of the driver transistor. so, i guess its a bad transistor. I did some voltege measurements, and there is about 41VDC on the collector. There is 158VDC B+ on the HOT. I did a BtoC, and BtoE check in circuit on the transistor, and it checks OK, but i never pulled it out of circuit. Any Ideas? "Q.E.D." wrote in message ... Looking for input into whether this June 1996 build TV is worth having repaired. TV has worked great since purchase in 1996. Never got a great deal of use...maybe 10 hours a week on weekends to watch mainly movies on DVD or HBO. I figure less than 4000 hours total use. Set had been on for about 4 hours one day and the picture just went blank...like someone turned it off. No warning of trouble before that...no picture fade or blooming, it just went dark. Sound still works OK. The TV is long out of warranty but due to it's light use I was thinking it might be worth repairing. Can anyone give me an idea how much would be a fair rate for a repairman to come out and diagnose (I live in Philadelphia, PA)? What's an average repair cost on a 35" set? I realize the repair costs would be on top of the initial estimate depending on what is wrong. On that note, are my TV's symptoms indicative of a common problem? Based on my novice research I think it could be a high voltage problem. The neighborhood repair guy went out of business about three years ago. Choosing a repair service, I'm finding, is almost impossible to decide on blindly. Any advice would be appreciated. Thanks |
#17
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
the only information i can tell you about the amplitude, is that the
waveform at the base is a little weaker than it is comming out of the IC, "Bill Jr" wrote in message ... IS the frequency of that square wave accurate? IS the amplitude sufficient to turn on the horiz driver transistor? Bill Jr "Mike" wrote in message ... P.S., the heatsink on the QX3201 stays cool. the other 3 in the chopper circuit get regularly warm, thats the only one that stays cold. could that be something? it junction tests good. "Mike" wrote in message ... ok, I finally got to it. All volteges are presant and none of the fuses are blown. now, there was a pin problem. Now, I set my scope up, and did some more testing on the tv, the scan gen IS working. there is a square wave pulse on the pin 8. there is a square wave pulse on the base of the horizontal driver transistor. BUT, there is NO DRIVE PULSE on the collector of the driver transistor. so, i guess its a bad transistor. I did some voltege measurements, and there is about 41VDC on the collector. There is 158VDC B+ on the HOT. I did a BtoC, and BtoE check in circuit on the transistor, and it checks OK, but i never pulled it out of circuit. Any Ideas? "Q.E.D." wrote in message ... Looking for input into whether this June 1996 build TV is worth having repaired. TV has worked great since purchase in 1996. Never got a great deal of use...maybe 10 hours a week on weekends to watch mainly movies on DVD or HBO. I figure less than 4000 hours total use. Set had been on for about 4 hours one day and the picture just went blank...like someone turned it off. No warning of trouble before that...no picture fade or blooming, it just went dark. Sound still works OK. The TV is long out of warranty but due to it's light use I was thinking it might be worth repairing. Can anyone give me an idea how much would be a fair rate for a repairman to come out and diagnose (I live in Philadelphia, PA)? What's an average repair cost on a 35" set? I realize the repair costs would be on top of the initial estimate depending on what is wrong. On that note, are my TV's symptoms indicative of a common problem? Based on my novice research I think it could be a high voltage problem. The neighborhood repair guy went out of business about three years ago. Choosing a repair service, I'm finding, is almost impossible to decide on blindly. Any advice would be appreciated. Thanks |
#18
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
Why not just take the set to a TV shop and get a proffessional
to take a look and advise you , its pretty obvious you dont have the skills. kip yea im stupid, if thats the only way to find out whats wrong, because other approatches just arnt working. |
#19
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
excuse me?
I work at a shop. "john" wrote in message .. . Why not just take the set to a TV shop and get a proffessional to take a look and advise you , its pretty obvious you dont have the skills. kip yea im stupid, if thats the only way to find out whats wrong, because other approatches just arnt working. |
#20
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
you may be right about not exciting the driver.
Here is what I have come up with. There is 1.8VDC comming into the board through the cable comming from the scan gen IC, and there is only .1VDC at the driver. and 41vdc at the collector. any ideas? and there should be 5V p-p comming from the IC, but it might go through resistors, dropping it down. "Bill Jr" wrote in message ... IS the frequency of that square wave accurate? IS the amplitude sufficient to turn on the horiz driver transistor? Bill Jr "Mike" wrote in message ... P.S., the heatsink on the QX3201 stays cool. the other 3 in the chopper circuit get regularly warm, thats the only one that stays cold. could that be something? it junction tests good. "Mike" wrote in message ... ok, I finally got to it. All volteges are presant and none of the fuses are blown. now, there was a pin problem. Now, I set my scope up, and did some more testing on the tv, the scan gen IS working. there is a square wave pulse on the pin 8. there is a square wave pulse on the base of the horizontal driver transistor. BUT, there is NO DRIVE PULSE on the collector of the driver transistor. so, i guess its a bad transistor. I did some voltege measurements, and there is about 41VDC on the collector. There is 158VDC B+ on the HOT. I did a BtoC, and BtoE check in circuit on the transistor, and it checks OK, but i never pulled it out of circuit. Any Ideas? "Q.E.D." wrote in message ... Looking for input into whether this June 1996 build TV is worth having repaired. TV has worked great since purchase in 1996. Never got a great deal of use...maybe 10 hours a week on weekends to watch mainly movies on DVD or HBO. I figure less than 4000 hours total use. Set had been on for about 4 hours one day and the picture just went blank...like someone turned it off. No warning of trouble before that...no picture fade or blooming, it just went dark. Sound still works OK. The TV is long out of warranty but due to it's light use I was thinking it might be worth repairing. Can anyone give me an idea how much would be a fair rate for a repairman to come out and diagnose (I live in Philadelphia, PA)? What's an average repair cost on a 35" set? I realize the repair costs would be on top of the initial estimate depending on what is wrong. On that note, are my TV's symptoms indicative of a common problem? Based on my novice research I think it could be a high voltage problem. The neighborhood repair guy went out of business about three years ago. Choosing a repair service, I'm finding, is almost impossible to decide on blindly. Any advice would be appreciated. Thanks |
#21
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
C3203 I guess either opened or changed in value.
it was 1.8Vp-p on one side, and .1vp-p on the other. I shunted the cap, and as soon as I powered it up, the flyback made a sick ring, and instantly shorted the HOT. back to square 1. that cap, i THINK was the problem. then the flyback made a sick ring for a sec, i could hear the HV comming up, and blew the HOT. bad flyback or focus block? "Bill Jr" wrote in message ... IS the frequency of that square wave accurate? IS the amplitude sufficient to turn on the horiz driver transistor? Bill Jr "Mike" wrote in message ... P.S., the heatsink on the QX3201 stays cool. the other 3 in the chopper circuit get regularly warm, thats the only one that stays cold. could that be something? it junction tests good. "Mike" wrote in message ... ok, I finally got to it. All volteges are presant and none of the fuses are blown. now, there was a pin problem. Now, I set my scope up, and did some more testing on the tv, the scan gen IS working. there is a square wave pulse on the pin 8. there is a square wave pulse on the base of the horizontal driver transistor. BUT, there is NO DRIVE PULSE on the collector of the driver transistor. so, i guess its a bad transistor. I did some voltege measurements, and there is about 41VDC on the collector. There is 158VDC B+ on the HOT. I did a BtoC, and BtoE check in circuit on the transistor, and it checks OK, but i never pulled it out of circuit. Any Ideas? "Q.E.D." wrote in message ... Looking for input into whether this June 1996 build TV is worth having repaired. TV has worked great since purchase in 1996. Never got a great deal of use...maybe 10 hours a week on weekends to watch mainly movies on DVD or HBO. I figure less than 4000 hours total use. Set had been on for about 4 hours one day and the picture just went blank...like someone turned it off. No warning of trouble before that...no picture fade or blooming, it just went dark. Sound still works OK. The TV is long out of warranty but due to it's light use I was thinking it might be worth repairing. Can anyone give me an idea how much would be a fair rate for a repairman to come out and diagnose (I live in Philadelphia, PA)? What's an average repair cost on a 35" set? I realize the repair costs would be on top of the initial estimate depending on what is wrong. On that note, are my TV's symptoms indicative of a common problem? Based on my novice research I think it could be a high voltage problem. The neighborhood repair guy went out of business about three years ago. Choosing a repair service, I'm finding, is almost impossible to decide on blindly. Any advice would be appreciated. Thanks |
#22
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
the capacitor was bad.
when I changed it, boom. I had a pulse on the base of the HOT. im not sure if its a good pulse or not, but from most tv experiance its pretty damn close, give or take a scope calibration. now, I need a flyback. it made a sick squeek and blew HOT. i pulled it out and checked the waveform, it has one now. but since that incedent, the B+ is now gone. even with the transistor out. i guess one of the fuses went, but the sound is still there. "Mike" wrote in message ... C3203 I guess either opened or changed in value. it was 1.8Vp-p on one side, and .1vp-p on the other. I shunted the cap, and as soon as I powered it up, the flyback made a sick ring, and instantly shorted the HOT. back to square 1. that cap, i THINK was the problem. then the flyback made a sick ring for a sec, i could hear the HV comming up, and blew the HOT. bad flyback or focus block? "Bill Jr" wrote in message ... IS the frequency of that square wave accurate? IS the amplitude sufficient to turn on the horiz driver transistor? Bill Jr "Mike" wrote in message ... P.S., the heatsink on the QX3201 stays cool. the other 3 in the chopper circuit get regularly warm, thats the only one that stays cold. could that be something? it junction tests good. "Mike" wrote in message ... ok, I finally got to it. All volteges are presant and none of the fuses are blown. now, there was a pin problem. Now, I set my scope up, and did some more testing on the tv, the scan gen IS working. there is a square wave pulse on the pin 8. there is a square wave pulse on the base of the horizontal driver transistor. BUT, there is NO DRIVE PULSE on the collector of the driver transistor. so, i guess its a bad transistor. I did some voltege measurements, and there is about 41VDC on the collector. There is 158VDC B+ on the HOT. I did a BtoC, and BtoE check in circuit on the transistor, and it checks OK, but i never pulled it out of circuit. Any Ideas? "Q.E.D." wrote in message ... Looking for input into whether this June 1996 build TV is worth having repaired. TV has worked great since purchase in 1996. Never got a great deal of use...maybe 10 hours a week on weekends to watch mainly movies on DVD or HBO. I figure less than 4000 hours total use. Set had been on for about 4 hours one day and the picture just went blank...like someone turned it off. No warning of trouble before that...no picture fade or blooming, it just went dark. Sound still works OK. The TV is long out of warranty but due to it's light use I was thinking it might be worth repairing. Can anyone give me an idea how much would be a fair rate for a repairman to come out and diagnose (I live in Philadelphia, PA)? What's an average repair cost on a 35" set? I realize the repair costs would be on top of the initial estimate depending on what is wrong. On that note, are my TV's symptoms indicative of a common problem? Based on my novice research I think it could be a high voltage problem. The neighborhood repair guy went out of business about three years ago. Choosing a repair service, I'm finding, is almost impossible to decide on blindly. Any advice would be appreciated. Thanks |
#23
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
one more thing, the square wave pulse is continous, its not shutting
down, probably because its not getting to the flyback, or the base of the HOT, it dies off at the driver xistor. its there on the base, gone on the collector Forgive me for being blunt, but it sounds more like you're experimenting, not repairing. You should have checked the simple stuff first, like bad caps or even cold joints, but you automatically assumed that it was a major problem. When you thought it may have been a cap, you shunted it in circuit?! What you should have done was take the suspected cap out of the chassis and tested it for high ESR and to see if it can hold to its rated capacity. - Reinhart |
#24
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
no, no no, you must have not read my other posts.
the cap was changed in value, and I replaced it, I only shunted it to see if I had a drive at the base, which I did. as for experimenting, that is my way of troubleshooting, or basically tracing something back until it stops, and then look around in the circuit for bad parts in the area that stopped, and thats the area that had the nearly open cap. so, thats how I troubleshoot things, and I dont have a schematic, nor feel like ordering one for any TV I do, and it works for me every time. I have fixed every TV i ran into so far. I just study the boards, then do my work. I dont need to have experiance in "one or another chassis", It would be nice, but I dont. I just get down to the basics. I know how each function, and each circuit works, and I study the boards to examine and show me how the circuit is designed. "LASERandDVDfan" wrote in message ... one more thing, the square wave pulse is continous, its not shutting down, probably because its not getting to the flyback, or the base of the HOT, it dies off at the driver xistor. its there on the base, gone on the collector Forgive me for being blunt, but it sounds more like you're experimenting, not repairing. You should have checked the simple stuff first, like bad caps or even cold joints, but you automatically assumed that it was a major problem. When you thought it may have been a cap, you shunted it in circuit?! What you should have done was take the suspected cap out of the chassis and tested it for high ESR and to see if it can hold to its rated capacity. - Reinhart |
#25
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
this is how I work, my technique of troubleshooting is half and half, both
expermintation, and troubleshooting, but it works for me everytime. "LASERandDVDfan" wrote in message ... one more thing, the square wave pulse is continous, its not shutting down, probably because its not getting to the flyback, or the base of the HOT, it dies off at the driver xistor. its there on the base, gone on the collector Forgive me for being blunt, but it sounds more like you're experimenting, not repairing. You should have checked the simple stuff first, like bad caps or even cold joints, but you automatically assumed that it was a major problem. When you thought it may have been a cap, you shunted it in circuit?! What you should have done was take the suspected cap out of the chassis and tested it for high ESR and to see if it can hold to its rated capacity. - Reinhart |
#26
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
another thing, I didnt automattically assume. I have made posts in the past,
people like jerry greenberg and bill jr know what happened, and what I have been trying to approatch. "LASERandDVDfan" wrote in message ... one more thing, the square wave pulse is continous, its not shutting down, probably because its not getting to the flyback, or the base of the HOT, it dies off at the driver xistor. its there on the base, gone on the collector Forgive me for being blunt, but it sounds more like you're experimenting, not repairing. You should have checked the simple stuff first, like bad caps or even cold joints, but you automatically assumed that it was a major problem. When you thought it may have been a cap, you shunted it in circuit?! What you should have done was take the suspected cap out of the chassis and tested it for high ESR and to see if it can hold to its rated capacity. - Reinhart |
#27
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
I shunted the cap with a cap of the same value and ratings.
so, it tells me to do these things in my repair handbooks. Thats how I learned how to even deal with electronics, more or less, repair them. unless you want to confront Homer L. Davidson. "LASERandDVDfan" wrote in message ... one more thing, the square wave pulse is continous, its not shutting down, probably because its not getting to the flyback, or the base of the HOT, it dies off at the driver xistor. its there on the base, gone on the collector Forgive me for being blunt, but it sounds more like you're experimenting, not repairing. You should have checked the simple stuff first, like bad caps or even cold joints, but you automatically assumed that it was a major problem. When you thought it may have been a cap, you shunted it in circuit?! What you should have done was take the suspected cap out of the chassis and tested it for high ESR and to see if it can hold to its rated capacity. - Reinhart |
#28
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
you must have not read my other posts.
the cap was changed in value, and I replaced it, I only shunted it to see if I had a drive at the base, which I did. as for experimenting, that is my way of troubleshooting, or basically tracing something back until it stops, and then look around in the circuit for bad parts in the area that stopped, and thats the area that had the nearly open cap. so, thats how I troubleshoot things, and I dont have a schematic, nor feel like ordering one for any TV I do, and it works for me every time. I have fixed every TV i ran into so far. I just study the boards, then do my work. I dont need to have experiance in "one or another chassis", It would be nice, but I dont. I just get down to the basics. I know how each function, and each circuit works, and I study the boards to examine and show me how the circuit is designed. "LASERandDVDfan" wrote in message ... one more thing, the square wave pulse is continous, its not shutting down, probably because its not getting to the flyback, or the base of the HOT, it dies off at the driver xistor. its there on the base, gone on the collector Forgive me for being blunt, but it sounds more like you're experimenting, not repairing. You should have checked the simple stuff first, like bad caps or even cold joints, but you automatically assumed that it was a major problem. When you thought it may have been a cap, you shunted it in circuit?! What you should have done was take the suspected cap out of the chassis and tested it for high ESR and to see if it can hold to its rated capacity. - Reinhart |
#29
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
That is how I work, my technique of troubleshooting is half and half, both
expermintation, and troubleshooting, but it works for me everytime. "LASERandDVDfan" wrote in message ... one more thing, the square wave pulse is continous, its not shutting down, probably because its not getting to the flyback, or the base of the HOT, it dies off at the driver xistor. its there on the base, gone on the collector Forgive me for being blunt, but it sounds more like you're experimenting, not repairing. You should have checked the simple stuff first, like bad caps or even cold joints, but you automatically assumed that it was a major problem. When you thought it may have been a cap, you shunted it in circuit?! What you should have done was take the suspected cap out of the chassis and tested it for high ESR and to see if it can hold to its rated capacity. - Reinhart |
#30
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
I didnt automattically assume. I have made posts in the past,
people like jerry greenberg and bill jr know what happened, and what I have been trying to approatch. "LASERandDVDfan" wrote in message ... one more thing, the square wave pulse is continous, its not shutting down, probably because its not getting to the flyback, or the base of the HOT, it dies off at the driver xistor. its there on the base, gone on the collector Forgive me for being blunt, but it sounds more like you're experimenting, not repairing. You should have checked the simple stuff first, like bad caps or even cold joints, but you automatically assumed that it was a major problem. When you thought it may have been a cap, you shunted it in circuit?! What you should have done was take the suspected cap out of the chassis and tested it for high ESR and to see if it can hold to its rated capacity. - Reinhart |
#31
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
I shunted the cap with a cap of the same value and ratings.
so, it tells me to do these things in my repair handbooks. Thats how I learned how to even deal with electronics, more or less, repair them. unless you want to confront Homer L. Davidson "LASERandDVDfan" wrote in message ... one more thing, the square wave pulse is continous, its not shutting down, probably because its not getting to the flyback, or the base of the HOT, it dies off at the driver xistor. its there on the base, gone on the collector Forgive me for being blunt, but it sounds more like you're experimenting, not repairing. You should have checked the simple stuff first, like bad caps or even cold joints, but you automatically assumed that it was a major problem. When you thought it may have been a cap, you shunted it in circuit?! What you should have done was take the suspected cap out of the chassis and tested it for high ESR and to see if it can hold to its rated capacity. - Reinhart |
#32
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
The capacitor wasnt even an electrolytic, it was blue, and polyester type
one or something like that. I did check bad joints, that was the whole problem in the first place. The picture was too wide, and it was bowed in, and I recieved it with no horizontal deflection, but it had HV. well, just shortly after the flyback began to squeel, squal like it shorted, and as soon as it did, it lost the picture as it was squeeling, and then it blew the HOT, and it took me awhile to find out it opened a series cap to the drive transistor. I pulled the HOT to run tests, I shunted the cap, and the drive came back. I replaced it, and then put the HOT back in, and tried to power it up, the flyback made the same squeel, but it only happened for a split second before the HOT shorted again. I heard the static pops, like the HV was trying to kick up, the HV was there and gone under a second. "LASERandDVDfan" wrote in message ... one more thing, the square wave pulse is continous, its not shutting down, probably because its not getting to the flyback, or the base of the HOT, it dies off at the driver xistor. its there on the base, gone on the collector Forgive me for being blunt, but it sounds more like you're experimenting, not repairing. You should have checked the simple stuff first, like bad caps or even cold joints, but you automatically assumed that it was a major problem. When you thought it may have been a cap, you shunted it in circuit?! What you should have done was take the suspected cap out of the chassis and tested it for high ESR and to see if it can hold to its rated capacity. - Reinhart |
#33
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
Man !
|
#34
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
what do you mean by that.
I am a damn good technician, Its just the way I try to describe things. like im a blooming ideot. but, im not, I can verify that one. "john" wrote in message .. . Man ! |
#35
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
Hi!
A Technician would never ever think of disableing the Shut Down circuit like you wish to do. Do it the correct way ..The right way. Not say who is or is not, but sometimes you've got to disable a protection or shutdown circuit to fix a problem--even if the only result is burning up something. I'm not a tech, and I haven't had to do so very often, but sometimes it just takes a "plug 'er in and see what smokes" test to get to the bottom of something. William |
#36
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
You are totally wrong William with your thinking
a real Tech would never ever disable a shutdown circuit, maybe a non tech Guy would as per yourself. I have been in this buis for 36 yrs and have never even thought of disableing one to find a fault. Do it the right way........... kip Not say who is or is not, but sometimes you've got to disable a protection or shutdown circuit to fix a problem--even if the only result is burning up something. I'm not a tech, and I haven't had to do so very often, but sometimes it just takes a "plug 'er in and see what smokes" test to get to the bottom of something. William |
#37
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
you can get a life, and get lost.
"john" wrote in message .. . You are totally wrong William with your thinking a real Tech would never ever disable a shutdown circuit, maybe a non tech Guy would as per yourself. I have been in this buis for 36 yrs and have never even thought of disableing one to find a fault. Do it the right way........... kip Not say who is or is not, but sometimes you've got to disable a protection or shutdown circuit to fix a problem--even if the only result is burning up something. I'm not a tech, and I haven't had to do so very often, but sometimes it just takes a "plug 'er in and see what smokes" test to get to the bottom of something. William |
#38
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
FYI you can disable a shutdown circuit as a last resort for troubleshooting
when all standard procedures with the schematic fail but NEVER the XRAY protect, PERIOD. There are far too many other safe ways to troubleshoot a problem that triggers the xray protect. i.e. lowering the B+ voltage to the flyback circuit for one. BTW you still need to pull the shaping coil and pincushion coil on that set as those are very common failure items, as are electrolytic capacitors in the smps and the little filter one on the hv driver coil, as well as high failure of the flyback tripler causing an effective short (for 25kv) between the hv anode and ground, plus the tubes have been known to arc back to the yoke and blow a hole in the glass on these from flyback failure. David Mike wrote in message ... john, now that you told me off, and told him off, I see that YOUR NOT a technician, and you need to kiss my ass and bug off. "john" wrote in message .. . You are totally wrong William with your thinking a real Tech would never ever disable a shutdown circuit, maybe a non tech Guy would as per yourself. I have been in this buis for 36 yrs and have never even thought of disableing one to find a fault. Do it the right way........... kip Not say who is or is not, but sometimes you've got to disable a protection or shutdown circuit to fix a problem--even if the only result is burning up something. I'm not a tech, and I haven't had to do so very often, but sometimes it just takes a "plug 'er in and see what smokes" test to get to the bottom of something. William |
#39
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
On Sun, 3 Aug 2003 19:42:49 -0500, "David"
wrote: FYI you can disable a shutdown circuit as a last resort for troubleshooting when all standard procedures with the schematic fail but NEVER the XRAY protect, PERIOD. I have done this once, awhile back, when I was feeling my way along in the on the job learning process...disabled the XRP, fired the set up, heard the crackle of the HV, shut it off, knowing my suspicions were confirmed. What would've/could've happened in that one second that is that serious? Just asking... In that case it was a faulty component in the XRP, and not excessive XRP that caused the problem. I forget the make/model of the set. I have a bit of training in the operation of another type of device that uses X-rays and, despite the fact that its radiation levels in operation are far less than some normal daily situations, the specific precautions against any exposure are stringent. X-rays have a lot of respect, don't they? Tom David just takes a "plug 'er in and see what smokes" test to get to the bottom of something. William |
#40
|
|||
|
|||
Zenith SR3587DT Sound OK, No Picture????
i meant that for john. no one else, but john.
anyway, I didnt need to. I "assume" the flyback is bad, it is showing all the symptoms of it, and I need to do further testing to do so. but since the HOT shorted for the second time, I pulled the HOT, and I no longer have B+ at the collector pad. I guess either the winding in the flyback opened, or the series fuse opened. "Mike" wrote in message ... you can get a life, and get lost. "john" wrote in message .. . You are totally wrong William with your thinking a real Tech would never ever disable a shutdown circuit, maybe a non tech Guy would as per yourself. I have been in this buis for 36 yrs and have never even thought of disableing one to find a fault. Do it the right way........... kip Not say who is or is not, but sometimes you've got to disable a protection or shutdown circuit to fix a problem--even if the only result is burning up something. I'm not a tech, and I haven't had to do so very often, but sometimes it just takes a "plug 'er in and see what smokes" test to get to the bottom of something. William |
Reply |
|
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
Horizontal width of picture, RCA console | Electronics | |||
Simple question regarding Ceiling tiles and sound? | UK diy | |||
Zenith TV problems | Electronics Repair |