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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. |
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#1
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Citizen 27 inch color TV Model #C27401
Having big issues in solving this problem.
Power switch on this model is mechanical. Here is the Problem......... Push the power switch on and the red light lights up. That's all..... No High voltage, no audio, absolutely dead. I checked the voltage reg....OK I checked the HOT....OK Checked ossilator HOT coil.....OK Checked flyback......OK Looked for cold solder joint....seems ok Checked all power resistors...OK Can't seem to find a schematic for this model either. This TV is fairly new with hardly any use on it at all.. I checked with other techies in my area and they have a couple of these TV's on their bench as well with the same problem... I am stumped on this one.... :-( I need some help on this one... Any suggestions? Thanks in advance Michael Bearns |
#3
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Citizen 27 inch color TV Model #C27401
wrote:
Having big issues in solving this problem. Power switch on this model is mechanical. Here is the Problem......... Push the power switch on and the red light lights up. That's all..... No High voltage, no audio, absolutely dead. I checked the voltage reg....OK I checked the HOT....OK Checked ossilator HOT coil.....OK Checked flyback......OK Looked for cold solder joint....seems ok Checked all power resistors...OK Can't seem to find a schematic for this model either. This TV is fairly new with hardly any use on it at all.. I checked with other techies in my area and they have a couple of these TV's on their bench as well with the same problem... I am stumped on this one.... :-( I need some help on this one... Any suggestions? Thanks in advance Michael Bearns Look for an onboard POWER RELAY, most likely in a black rectangular case. There was one very cheap TV, I once had my hands into that used the heater of the CRT as part of the power supply. if that opened, it would also not allow the power supply to start up. It was a good idea how ever, bad CRT's many times would cause major problems else where when things like ARC's took place. Also, look for the degaussing circuit which is suppose to time out and then switch on TV. It's been a while since I've really have had my head into TV's. I've found not much profit in them. Just more of a side line to help people out around me. -- "I'm never wrong, once i thought i was, but was mistaken" Real Programmers Do things like this. http://webpages.charter.net/jamie_5 |
#4
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Citizen 27 inch color TV Model #C27401
Jamie wrote:
wrote: Having big issues in solving this problem. Power switch on this model is mechanical. Here is the Problem......... Push the power switch on and the red light lights up. That's all..... No High voltage, no audio, absolutely dead. I checked the voltage reg....OK I checked the HOT....OK Checked ossilator HOT coil.....OK Checked flyback......OK Looked for cold solder joint....seems ok Checked all power resistors...OK Can't seem to find a schematic for this model either. This TV is fairly new with hardly any use on it at all.. I checked with other techies in my area and they have a couple of these TV's on their bench as well with the same problem... I am stumped on this one.... :-( I need some help on this one... Any suggestions? Thanks in advance Michael Bearns Look for an onboard POWER RELAY, most likely in a black rectangular case. There was one very cheap TV, I once had my hands into that used the heater of the CRT as part of the power supply. if that opened, it would also not allow the power supply to start up. It was a good idea how ever, bad CRT's many times would cause major problems else where when things like ARC's took place. Also, look for the degaussing circuit which is suppose to time out and then switch on TV. It's been a while since I've really have had my head into TV's. I've found not much profit in them. Just more of a side line to help people out around me. Thanks for the information jamie...... This TV does not have a relay..... CRT heater is working...... degaussing circuit does time out...... --------------------------------- :-( |
#5
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Citizen 27 inch color TV Model #C27401
wrote:
Jamie wrote: wrote: Having big issues in solving this problem. Power switch on this model is mechanical. Here is the Problem......... Push the power switch on and the red light lights up. That's all..... No High voltage, no audio, absolutely dead. I checked the voltage reg....OK I checked the HOT....OK Checked ossilator HOT coil.....OK Checked flyback......OK Looked for cold solder joint....seems ok Checked all power resistors...OK Can't seem to find a schematic for this model either. This TV is fairly new with hardly any use on it at all.. I checked with other techies in my area and they have a couple of these TV's on their bench as well with the same problem... I am stumped on this one.... :-( I need some help on this one... Any suggestions? Thanks in advance Michael Bearns Look for an onboard POWER RELAY, most likely in a black rectangular case. There was one very cheap TV, I once had my hands into that used the heater of the CRT as part of the power supply. if that opened, it would also not allow the power supply to start up. It was a good idea how ever, bad CRT's many times would cause major problems else where when things like ARC's took place. Also, look for the degaussing circuit which is suppose to time out and then switch on TV. It's been a while since I've really have had my head into TV's. I've found not much profit in them. Just more of a side line to help people out around me. Thanks for the information jamie...... This TV does not have a relay..... CRT heater is working...... degaussing circuit does time out...... -------------------------------------------- :-( Well, Have you check to see if there is any HV B+ at the collector of the HOT ? Open yoke and flybacks can also cause issues. A lot of times, You need a feed back voltage from the flyback which is normally a low voltage supply for the rest of the unit. it's also used to insure power is good and keep the main supply on. normally, a momentary flicker of this voltage will cause main supply shut down.. Some times its simply bad caps at this section of the unit and thus will produce a line pulse effectively the same as a transient pulse that disables the main supply.. What you need to do is connect a scope to this and see if you're getting a brief signal to the HOT Base and collector and also look at any low voltage secondary taps for badly filtered supply outputs that will show as a pulse on start attempt. Happy hunting. -- "I'm never wrong, once i thought i was, but was mistaken" Real Programmers Do things like this. http://webpages.charter.net/jamie_5 |
#6
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Citizen 27 inch color TV Model #C27401
Jamie wrote:
wrote: Jamie wrote: wrote: Having big issues in solving this problem. Power switch on this model is mechanical. Here is the Problem......... Push the power switch on and the red light lights up. That's all..... No High voltage, no audio, absolutely dead. I checked the voltage reg....OK I checked the HOT....OK Checked ossilator HOT coil.....OK Checked flyback......OK Looked for cold solder joint....seems ok Checked all power resistors...OK Can't seem to find a schematic for this model either. This TV is fairly new with hardly any use on it at all.. I checked with other techies in my area and they have a couple of these TV's on their bench as well with the same problem... I am stumped on this one.... :-( I need some help on this one... Any suggestions? Thanks in advance Michael Bearns Look for an onboard POWER RELAY, most likely in a black rectangular case. There was one very cheap TV, I once had my hands into that used the heater of the CRT as part of the power supply. if that opened, it would also not allow the power supply to start up. It was a good idea how ever, bad CRT's many times would cause major problems else where when things like ARC's took place. Also, look for the degaussing circuit which is suppose to time out and then switch on TV. It's been a while since I've really have had my head into TV's. I've found not much profit in them. Just more of a side line to help people out around me. Thanks for the information jamie...... This TV does not have a relay..... CRT heater is working...... degaussing circuit does time out...... -------------------------------------------- :-( Well, Have you check to see if there is any HV B+ at the collector of the HOT ? Open yoke and flybacks can also cause issues. A lot of times, You need a feed back voltage from the flyback which is normally a low voltage supply for the rest of the unit. it's also used to insure power is good and keep the main supply on. normally, a momentary flicker of this voltage will cause main supply shut down.. Some times its simply bad caps at this section of the unit and thus will produce a line pulse effectively the same as a transient pulse that disables the main supply.. What you need to do is connect a scope to this and see if you're getting a brief signal to the HOT Base and collector and also look at any low voltage secondary taps for badly filtered supply outputs that will show as a pulse on start attempt. Happy hunting. I have checked the yoke for opens.....OK Flyback has been replaced.... No Change All Caps are within their specs.... high voltage section. B+ voltage is their as well..... scope is being serviced and calibrated at this time, so this is not an option..... I am going to check the other things you mentioned tommorrow as I'm getting eye strain. lol thanks for the info....... |
#7
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Citizen 27 inch color TV Model #C27401
Does the remote work? had one of these with dead like yours and when
you pushed the button on with the tv set would not fire up but the remote worked. once the set was turned on the switch on the tv would work properly Mechanical Power switch on the tv was flakey On Oct 9, 6:23 pm, wrote: Having big issues in solving this problem. Power switch on this model is mechanical. Here is the Problem......... Push the power switch on and the red light lights up. That's all..... No High voltage, no audio, absolutely dead. I checked the voltage reg....OK I checked the HOT....OK Checked ossilator HOT coil.....OK Checked flyback......OK Looked for cold solder joint....seems ok Checked all power resistors...OK Can't seem to find a schematic for this model either. This TV is fairly new with hardly any use on it at all.. I checked with other techies in my area and they have a couple of these TV's on their bench as well with the same problem... I am stumped on this one.... :-( I need some help on this one... Any suggestions? Thanks in advance Michael Bearns |
#8
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Citizen 27 inch color TV Model #C27401
Power switch is working fine......
I have the remote as well and that is working as well....... I checked what I could without a schematic. Everything I did checked seem to be working.... I'm at my wits end...... From what I gathered this tv has only been on a couple of times and is fairly new... I just can't figure this one out.... it might be a life time project...LOL ------------------------------- wrote: Does the remote work? had one of these with dead like yours and when you pushed the button on with the tv set would not fire up but the remote worked. once the set was turned on the switch on the tv would work properly Mechanical Power switch on the tv was flakey On Oct 9, 6:23 pm, wrote: Having big issues in solving this problem. Power switch on this model is mechanical. Here is the Problem......... Push the power switch on and the red light lights up. That's all..... No High voltage, no audio, absolutely dead. I checked the voltage reg....OK I checked the HOT....OK Checked ossilator HOT coil.....OK Checked flyback......OK Looked for cold solder joint....seems ok Checked all power resistors...OK Can't seem to find a schematic for this model either. This TV is fairly new with hardly any use on it at all.. I checked with other techies in my area and they have a couple of these TV's on their bench as well with the same problem... I am stumped on this one.... :-( I need some help on this one... Any suggestions? Thanks in advance Michael Bearns |
#9
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Citizen 27 inch color TV Model #C27401
I doubled checked what you have said about the switch and remote.
Since I could not find a defective part in the TV set, Maybe I was looking for the big picture, excuse the pun. I tried one of my universal remotes on the set and randomly entered the automatic scan from the remote that i had. bingo! the set came on. I took apart the factory remote and the LED was broken off the board. I resoldered the led and put fresh batteries in the remote and it works perfectly. The switch on the tv does not turn on the tv. the switch is used to put the tv on stand by mode so it can receive information from the remote. I feel pretty foolish at this point and egg on my face. 30 years in the business and I get stumped on a simple problem/fix. I won't forget this fix ever. In conclusion, I thank you for the diagnoses on the remote, you were spot on. Problem has been solved and also would thank the others who had suggestion for me in the repair of this TV. Michael Bearns :-) ------------------- wrote: Power switch is working fine...... I have the remote as well and that is working as well....... I checked what I could without a schematic. Everything I did checked seem to be working.... I'm at my wits end...... From what I gathered this tv has only been on a couple of times and is fairly new... I just can't figure this one out.... it might be a life time project...LOL ------------------------------- wrote: Does the remote work? had one of these with dead like yours and when you pushed the button on with the tv set would not fire up but the remote worked. once the set was turned on the switch on the tv would work properly Mechanical Power switch on the tv was flakey On Oct 9, 6:23 pm, wrote: Having big issues in solving this problem. Power switch on this model is mechanical. Here is the Problem......... Push the power switch on and the red light lights up. That's all..... No High voltage, no audio, absolutely dead. I checked the voltage reg....OK I checked the HOT....OK Checked ossilator HOT coil.....OK Checked flyback......OK Looked for cold solder joint....seems ok Checked all power resistors...OK Can't seem to find a schematic for this model either. This TV is fairly new with hardly any use on it at all.. I checked with other techies in my area and they have a couple of these TV's on their bench as well with the same problem... I am stumped on this one.... :-( I need some help on this one... Any suggestions? Thanks in advance Michael Bearns |
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