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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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Panansonic TAU series CT-32SX31CE Thought I got it fixed but now have new questions
Even after this repair, TV still will not start even SMPS starts but
shuts down after a second see that on scope for smps (not like a direct short kind, SMPS runs for several seconds then slowly slows down and stops. TV uses small AC standby transformer for micro, it is working. LED power lights up then goes out, HOT is ok. History and what was done to it: TV HV won't start, SMPS shuts down like it does now. Found R517 burned and D507 shorted. Replaced both also flyback with the HV regulator transformer (baby flyback thing) as well. No luck the R517 and D509 are still intact. Anybody else? Have no schematic and we don't deal with Panasonic like we used to in past so getting schematic is not worth for us. Much appreciated, don't want to repeat that NV-55BX4 incident. Grrr. Cheers, Wizard |
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Do an ESR test on all the caps in the power supply and scan circuits. I am
sure you will find a number of them that are out of specs. If all the caps are good, then you will have to invest in the service manual and sped some time on it. -- Jerry G. ========================== "Jason D." wrote in message ... Even after this repair, TV still will not start even SMPS starts but shuts down after a second see that on scope for smps (not like a direct short kind, SMPS runs for several seconds then slowly slows down and stops. TV uses small AC standby transformer for micro, it is working. LED power lights up then goes out, HOT is ok. History and what was done to it: TV HV won't start, SMPS shuts down like it does now. Found R517 burned and D507 shorted. Replaced both also flyback with the HV regulator transformer (baby flyback thing) as well. No luck the R517 and D509 are still intact. Anybody else? Have no schematic and we don't deal with Panasonic like we used to in past so getting schematic is not worth for us. Much appreciated, don't want to repeat that NV-55BX4 incident. Grrr. Cheers, Wizard |
#3
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On Tue, 26 Oct 2004 21:58:56 -0400, "Jerry G."
wrote: Do an ESR test on all the caps in the power supply and scan circuits. I am sure you will find a number of them that are out of specs. If all the caps are good, then you will have to invest in the service manual and sped some time on it. -- Jerry G. True on the schematic problem is we only do very rarely service those newer sets like this. And panasonic pulled out on us few months ago because we don't do enough sets even we did do top notch job on these. So if I need info or parts I have to contact panasonic with component locations and order parts. We only did about 5 old and new in 12 month period. That's really few. On the caps on Tau, that's again true, in my experience Pansonic used really good caps stuff especially if the circuit design is cool. I got info from one other to check other items, Whew, that model likes to have so many bad resistors and one small cap. My rant: Just that, I am now wondering where RCA is going. Their sets is getting junkier again and cheap on packaging parts. I just got a 3.3V micro IC bare (big one inside the tin box of ITC222 chassis) with bent pins rattling around in that little RCA's red cardboard box without anything else to protect that IC. That is what Citizen does but I know RCA does best job on parts but now this one!? Oh, one more, there was a good part # but their dept discountined it less than a year for common 27" ITC008 chassis. RCA?! Also the RCA new component numbers types, 3 even 4 different types of fasteners on same TV, Quirky chassis design that is completely different way to pull out to service position, quirky ribbon connectors that you have to be so careful not to break those tiny plastic nubs off. really hate that. No sense of everything. Before ATC came, their CTC stuff were fine and had wonderful time working on it, I do have go looking forward to work on those CTC stuff. They were so predictable and easy to work on. At least JVC doesn't change too much on theirs chassis access too much which is great for me. Even Citizen is fine chassis to work on and actually is one of those brands with least problems as well as JVC and few others because we do keep stats on all brands we service and was least troublesome to diagnose. Samsung is great on parts for their projector, just recently I serviced one HCN 42" size model, this model has convergence amps mounted high up on the steel frame on small board. This was on replacing CRT and set of CRT boards (that set includes focus divider block!!) to save labor time and cost is minimal. Cost was inexpensive and easy to set up. That model did have convergence rings on their yokes. The CRT assy came in complete ready to put in (Yoke, Lense and all for about 250cdn) Unbelieveable. That RCA takes that cake for hard to service and shoddy parts for bad prices on newer chassis since ATC begun which is last year! :-O Their idea of plastic cabinet and need 100 T20 screws to take apart is nuts and have to lug big bases (aka light boxes) here and they're awkard to store compared to square and retangular light boxes of old. Oh, watch out for ITC008 chassis that has this cable that connect both chassis to the pincushion daughterboard, they're sneaky, touch that and problem is gone for days. Complaint is intermittent shut downs, less common is intermittent width. Solution: Cut ends off and remove pins, solder wires directly. That cable is made up of two brown and one blue wires with plugs at each end, usually black or cloudy milky. The problem lies with crimps on too small gauge wires. Watch out that cable isn't straight through. 1 and 3 pins are reversed, pin 2 straight through. No, this cable issue is not in part-finder's bulletin. It is like L14401 thing, sneaky but much worse and fairly common. Cheers, Wizard |
#4
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In article , Jason D.
writes Even after this repair, TV still will not start even SMPS starts but shuts down after a second see that on scope for smps (not like a direct short kind, SMPS runs for several seconds then slowly slows down and stops. Suggests lack of load to me. Check around for more open fusible resistors, etc. -- Rarely do people communicate; they just take turns talking. (source unknown) |
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