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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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Have an RCA F36450 tv set. ATC113 chassis. Not 1 year old yet. I
bought it at an auction "as-is" dead. Pulled the back off and found shorted hout. Checked for bad solder/cracks around h driver xformer etc. Found none, but resoldered many connections anyway. Replaced the hout with original RCA part. Set runs with a great picture for anywhere from 20 - 40 minutes. Then set starts to make ticking sound somewhere. Pic looks fine. Ticking freq increases, and gets to a point where pic starts to break up into horizontal garbage. If it stays this way for 1 second too long, hout xistor shorts. B+ stays at a steady 138 volts continuously. Have gone through 2 cans of freeze spray. Seems there are numerous components (including the hout, an 8 regulator, a .0015 cap etc) that when sprayed, the ticking stops. Have replaced these parts to no avail (I know- shots in the dark) Also have replaced the flyback with no change. Yesterday, once the ticking started, I sprayed what I think is the video processor Ic with freeze spray and the ticking stopped AND the set went dead. I allowed it to sit for 15 mins or so, and then set came on with good video and a very fast tick/squeal for about 2 seconds, then died again, this time taking out hout. Have resoldered many many connections. Also have tried flexing the board in different spots. No change. This set has a mind of its own. I see some noise in the signal at the base of the hout, but not sure of its origin. (or is it there because of load prob in hout being reflected backwards??) Again, the pic looks fine so I dont suspect the yoke or crt (unless some wierd intermittent thing). Any help HIGHLY appreciated, as this set is driving me to start drinking again !! 8-P Mike |
#3
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On 06 Aug 2003 12:08:41 GMT, (John Del) wrote:
Subject: RCA F36450 aka ATC113 From: (Gurkle) Date: 8/5/03 10:57 PM Eastern Daylight Time Message-id: Have an RCA F36450 tv set. ATC113 chassis. Not 1 year old yet. I bought it at an auction "as-is" dead. Pulled the back off and found Snip Again, the pic looks fine so I dont suspect the yoke or crt (unless some wierd intermittent thing). Any help HIGHLY appreciated, as this set is driving me to start drinking again !! 8-P Mike Change the jungle IC and the crystal. John Del Wolcott, CT Del, Certain? This ATC113 chassis is digital and been like this way since CTC17x. jungle is programmable so it doesn't use external components to set an H-freq, it's stored in eeprom. Replace flyback bec the pix is breaking up bec of radiated noise and audible noise (arcing) on internal G2 and stressing HOT to destruction. Also check that G2 cap for intemittent break down. New flyback for this one is not that expensive and worth fixing. Can see that noisy power with scope on G2 if you get ticking noise. Cheers, Wizard |
#4
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Subject: RCA F36450 aka ATC113
From: (Jason D.) Date: 8/7/03 1:11 AM Eastern Daylight Time Message-id: Del, Certain? This ATC113 chassis is digital and been like this way since CTC17x. jungle is programmable so it doesn't use external components to set an H-freq, it's stored in eeprom. Certain?, only about death and taxes. You're right, the reply I gave was sort of generic. It should have just read to replace the jungle. After that, he'll need to look around the jungle for a bad component. I'll bet almost anything though that the flyback isn't the problem. John |
#5
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On 07 Aug 2003 23:42:36 GMT, (John Del) wrote:
Subject: RCA F36450 aka ATC113 From: (Jason D.) Date: 8/7/03 1:11 AM Eastern Daylight Time Message-id: Del, Certain? This ATC113 chassis is digital and been like this way since CTC17x. jungle is programmable so it doesn't use external components to set an H-freq, it's stored in eeprom. Certain?, only about death and taxes. You're right, the reply I gave was sort of generic. It should have just read to replace the jungle. After that, he'll need to look around the jungle for a bad component. I'll bet almost anything though that the flyback isn't the problem. John Yeah, jungle IC might be bad, but also check that regulator for this ic is still good. Scope is required to confirm which is making noisy signal when ticking occurs. Look at G2, heater with scope. This's great way to watch the noises when ticking noise happens Oh, double check that L14401 has good solder joints. This how this kills the HOT also by feeding it with bad food. Bam! Jungle IC in RCA sets in general is rarely bad. Cheers, Wizard |
#6
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Thanks guys for your help. Have already replaced the flyback with no
change. Waiting for the jungle ic to get here. Got my fingers crossed. On Thu, 07 Aug 2003 05:11:50 GMT, (Jason D.) wrote: On 06 Aug 2003 12:08:41 GMT, (John Del) wrote: Subject: RCA F36450 aka ATC113 From: (Gurkle) Date: 8/5/03 10:57 PM Eastern Daylight Time Message-id: Have an RCA F36450 tv set. ATC113 chassis. Not 1 year old yet. I bought it at an auction "as-is" dead. Pulled the back off and found Snip Again, the pic looks fine so I dont suspect the yoke or crt (unless some wierd intermittent thing). Any help HIGHLY appreciated, as this set is driving me to start drinking again !! 8-P Mike Change the jungle IC and the crystal. John Del Wolcott, CT Del, Certain? This ATC113 chassis is digital and been like this way since CTC17x. jungle is programmable so it doesn't use external components to set an H-freq, it's stored in eeprom. Replace flyback bec the pix is breaking up bec of radiated noise and audible noise (arcing) on internal G2 and stressing HOT to destruction. Also check that G2 cap for intemittent break down. New flyback for this one is not that expensive and worth fixing. Can see that noisy power with scope on G2 if you get ticking noise. Cheers, Wizard |
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