PANASONIC TX-L32D28 - Blown fuses

[jondoe]

I have a new toy to tinker with, this time it's a PANASONIC TX-L32D28. The power board has blow both it's fuses, while poking around I tried to desolder one of the relays and broke it in the process , it's a DEC I can't find an equivalent of, so I ordered one from China on ebay, it's a DQ1U 12VDC DEC, if anyone is familiar? I think a HF36F012HST would cover it as a temp solution.

Any hoot, here's the board, no sign of bulging caps, no sign of anything burnt out, the two rectifiers on the hot side both check out OK Any ideas?

Thanks.

[jondoe]

Re: PANASONIC TX-L32D28 - Blown fuses

Thanks to some lovely Russians I've found some circuit for the N0AE4JJ00015 power supply! Attached for others to find

[jondoe]

Re: PANASONIC TX-L32D28 - Blown fuses

This tv is actually a TX-L37D28, but hey ho, I can't edit the title now

Further testing today revealed D210 and D211 to be faulty (bottom right, just above the floating transformer). They are marked "JE 1G5" - Google hasn't really helped with identifying those, anyone have an idea what they are?

The 1G5 rating does pop up on some diodes, but I can't find what the original is :/

[jondoe]

Re: PANASONIC TX-L32D28 - Blown fuses

I've found what appears to be another dead Diode (PCB has a diode symbol), this ones large and has a blue ring, T2D 04 I don't know if it's a Zener or not :/ Fails a Diode test, 0L in both directions, 1.6 mOhm, 0.9 mOhm in the other.

It looks near identical to these

[jondoe]

Re: PANASONIC TX-L32D28 - Blown fuses

This would be the weird diode I couldn't test, no wonder my meter didn't know what to do with it, that looks like two types of diodes in one package

[jondoe]

Re: PANASONIC TX-L32D28 - Blown fuses

Replaced D210 and D211 with a guess on the diode rating, seeing 6V at the P1 connector and no blown fuse. However, I'm waiting for the 12V relay to arrive, so fired it up without it.

If it doesn't pop after I've replaced that relay, I'll stick it in the TV and fire it up and see if it goes bang.

[jondoe]

Re: PANASONIC TX-L32D28 - Blown fuses

Well, my relay arrived and my physical dimensions were off, they don't fit in the board So there would be no 12v rail being turned on anytime soon.

I thought I'd put the board back in the TV and at least see if I got a standby light seeing as I had 6 volts on the 5.8v standby rail, however, there was a loud pop and now there's nothing, she's dead. More fool me.

There was a noticeable arch of electricity from Q202, the casing is a little scorched between drain and source pins, I pulled it but oddly enough it still tests fine on my component tester.

I seem to be getting 2.5volts on pin 12, which is the SOS and -3volts on the Relay pin.

I'd be grateful for an experts opinion, schematic attached

[jondoe]

Re: PANASONIC TX-L32D28 - Blown fuses

I've now found an odd 3 legged thermal resistor combo, which doesn't seem to be very well at all, it's RWT05 15ΩJ, (R003 on schematic). Although this has three legs, only two of them are in circuit, 1 leg is soldered in, but there are no tracks to it on the PCB (image attached) I suspect this is a test point of some kind?

I assume I can replace with a two legged alternative?

[jondoe]

Re: PANASONIC TX-L32D28 - Blown fuses

Have ordered a straight 5w 15ohn resistor, as far as I can tell this should be fine, it will just lack the thermal fuse, not as safe, but will allow the circuit to operate.

HF36F012HST was NOT a suitable replacement for the relay, so waiting on a couple of 2nd hand ones from China *gulp*


You ever get the feeling you're talking to yourself?

[jondoe]

Re: PANASONIC TX-L32D28 - Blown fuses

Replaced power resistor, replaced relay. mosfet still shorting out, although testing OK off the board. Fault clearly elsewhere, but beyond my low skills.

Replaced entire power supply board with second hand later revision (less parts) TV is now working fine.

Happy new year.