Panasonic TH-P42X10A no start

[maxvalutech]

Well opened up this set my first look inside a Panny and of course its plasma.
Symptoms are usual ones - been in storage for a year and start problem evident then - I plugged it in powered set up and it started ok showing "no signal" and the channel selected, went for about 2mins then turned off displaying 3 red blinks. I tried it again an hour or so later no start but now 2 red blinks. This set does not have a D board. No voltages marked on power board or main but I found standby was good 5v and went down on start attempt - the 3.3v also came up briefly but a click from A board I think turned it off. As an indication light on digital audio came on and went off as well. Haven't found a schematic as yet to find out whats what but does seem like the A board side is the problem. Nor have I isolated A board to test power board side as not familiar enough with it as yet Any assistance from Panny experts welcome of course.

[maxvalutech]

Re: Panasonic TH-P42X10A no start

This set was made 10/2009 so have downloaded info around that period even though not exact model but strong similarities evident. The set now displays just the 2 red blinks after the green start up flashing. This indicates problem with the 15v line. Service manual states check for short of power board from pin 1 on connector P6 - did this no short. It then states check for 15v on same pin - not present. On a straightforward basis this indicates power board problem BUT when I disconnect P6 lead to A main then pin 1 reads just under 12v !! it seems the A main is losing that voltage. The downloads are attached herein and do have circuit info on voltages etc. Any assistance or thoughts appreciated.

[maxvalutech]

Re: Panasonic TH-P42X10A no start

Well the joys of Panasonic. I studied circuitry in downloaded info then pulled main board only to find almost none of the basic components are identified ! So tracing out anything is not on. Small can caps have usual marking on top re uF and volts but there is only one on the front of board that's over 16v and one on the back as well - they are 25v and 35v respectively . Now having set up dmm beforehand I switched set on and did get very brief indication of good voltage at pin1 of main connector before the set clicked off. The click from main board is digital audio going off as set closes down. I still think problem is main board short and probably smd cap on the 15v line. Can't find a replacement board anywhere its TNPH0783 designator FA2A. Any input ???

[Doc38343]

Re: Panasonic TH-P42X10A no start

With the main board out of the TV, put your meter in diode mode (does it beep in that mode?) If it dosen't beep in diode mode put it in a mode that does.
put the RED probe on ground and start testing your SMD caps by carefully touching first one side then the other. Usually when you have a voltage draining short like your describing that is my goto search... SMD caps usually short when they fail.
If a cap beeps on both sides it means you have found the rail/trace the short is on and possibly the bad cap. However take it from a guy who removed 9 605 SMD caps just to find one short only to later realize I could have located it without removing all of them. I just needed to look at the schematic and follow the shorted path / traces to each end.
It could be an IC but I think you may be onto the right hunt.
I just did one and i haven't posted it yet but i plan to with a photo record of how i fixed that one. I fixed it basically with a .02 cent part. Last time i bought a A main for $59
Hope this helps a little.

[maxvalutech]

Re: Panasonic TH-P42X10A no start

Was having a breather and looking at eBay.au when I saw exact same model for sale from a pawnshop priced at $10 due "not turn on" so I bought it in hope main board OK. Also bought from them a 48" Viano and a 40" Soniq same problem they said. So 3 sets for $35 all up. The Soniq was home to a few generations of small cockroaches so took it all apart and cleaned it right up - it starts displays logo and chimes backlight stays on but no menus. The Viano seemed dead but side main switch was set off and I noticed pp plug was loose when plugged in so spread the contacts - it then started and running perfectly!!. And yes I started the Panasonic to check how many blinks etc but it also started OK and has been going great as well!! Not game enough now to push my luck and swap boards just in case that luck runs out.

[attainteddragon]

Re: Panasonic TH-P42X10A no start

lmao, i could not stop laughing as i would of done the same thing! :P

[maxvalutech]

Re: Panasonic TH-P42X10A no start

Took the back off set I bought that is working to check boards. Even though only 6 months between made date the main boards although very similar do have a couple of differences however power boards exactly the same so swapped them. Fault still the same so on the right track to troubleshoot main.