Chasing the 14 blinks on a Panasonic TC-P42S30

[Docatduq]

Hello all,

I picked up this tv for free and am trying to repair it. I've replaced the SS board and have the A board on order after receiving the wrong one. I checked continuity of the SN board by unplugging the p board connection and placing one probe on the chassis and one on the Vsus in lead and got a Beep (continuity) when I check the continuity of the new SS board when installed it shows rising resistance (assuming caps charging). I checked the Fets and diodes on the sn board while in circuit some were continuitous some were not (no beep) when I plug it in the led is solid and nothing happens. The second relay turns on when I push power. I have to hold power off then press power on again really quick to get to the 14 blinks.

Any help would be appreciated. I've researched through other threads and none have solved my problems.

[tvtimmy]

Re: Chasing the 14 blinks on a Panasonic TC-P42S30

Its the SC board.
#1 Check for short across both pins of SN2. A beep of 5 seconds or less is good, if it keeps beeping its short.
#2 Check Q401,402,421, & 422. Test all combos of the three legs. Any beep is bad. Remove them if bad.
#3 Check Q600. Beep is bad.
#4 Check Q441 & 451 for shorts the same way. Conferm by testing in diode mode.Remove bad ones(if any).
#5 check the I.C. buffer chips. There is a pad marked TPVFG on the bottom of the board, just under, and between, the last two I.C. chips. Put neg on it and drag the pos lead over the flat ribbon connectors pins. Do front and back.Any beep means a bad chip. At this point you can remove the bad one, or ones if you have the skills, or send it to be repaired.
New parts will blow up with bad buffer I.C.'s.
I use FGD4536 for the shorted out I.B.G.T.'s including the DG302.
Hope this helps.

[Docatduq]

Re: Chasing the 14 blinks on a Panasonic TC-P42S30

Thanks for the reply. When I write questions like this I always like to write out the basic stuff so I'm not missing stuff that's why I included the beeps . I'm assuming the IC chips are tough to track down.

I haven't done your tests yet I know the ribbon connections on the sn board are all good. I checked the front not the backs though. I'm assuming the sn and sc are integrated in my model because I've seen them separate but I have one large board on the left.

I've googled the fets you referenced and can really only get them on ebay. No digikey or mouser. I haven't looked at their data sheets yet to find a similar. I can try a local shop but they charge $8/fet. Any leads on a shop in the us that's reasonable? I'd rather not wait on the slow boat from china or pay 8/fet.

Thanks for all your help so far.

[Docatduq]

Re: Chasing the 14 blinks on a Panasonic TC-P42S30

Ok sooo the fets are bad. The ones at q401 q402 q421 and q422 and q600. I have a pack of FGD4536, however it looks like it'd only be fit to replace q600 and that I'll have to order others for the q400s

[tw2005]

Re: Chasing the 14 blinks on a Panasonic TC-P42S30

Ok sooo the fets are bad. The ones at q401 q402 q421 and q422 and q600. I have a pack of FGD4536, however it looks like it'd only be fit to replace q600 and that I'll have to order others for the q400s

Alarm bell ringing.

FGD4536 are IGBTs and are 360V 50A

Yes they are a smaller package than the 30F131 but it is possible to do the job with them.


Q600 is a FET, the full part number is RCD080N25 by ROHM and is a 250V 8A FET.

Do not use the FGD4536 for Q600

Check/confirm Q600 is shorted because I use my Fluke and it beeps but the FET is good with a reading of 0.5. Maybe go resistance and report.

Constant beep?

[Docatduq]

Re: Chasing the 14 blinks on a Panasonic TC-P42S30

Ok thank you for the reply. I'll replace the IFGBTs with what I purchased. I might be able to track down the fet down at a local shop.

I'm away from the tv right now but when I get back at it I'll remove the Q600 from the circuit and test the way I normally do.

I know that in circuit readings aren't always accurate and you have to pull the component before you truely know so I'm going to test everything I pull first.