Panisonic 42inch TCP42S30 not working!!

[Glitcher]

Re: Panisonic 42inch TCP42S30 not working!!

sorry just posted that and it refreshed, TW - saw your post...
what happens is 0L one way and .453 volts the other, on audible i get 0L both ways

That seems about right, that's the exact reading I had on mine. If it was still shorted it would just read low resistance no matter what setting you used.

Now you just need to get those parts replaced and youre good to go!

[Hok]

Re: Panisonic 42inch TCP42S30 not working!!

diode mode shows 0L in one direction and .453 volts in the opposite direction, and there is no audible in that mode.

to use the audible testing, I go to the 0))) setting, which offers a beep or constant beeping and measures in ohms

[tw2005]

Re: Panisonic 42inch TCP42S30 not working!!

thanks for those links, I first exhausted that search before I began to work on this. Understand your doubts about my abilities.... and I respect your patience, knowing what a pain it can be for you to think in Latin when i work in dogspeak
Using a Mastech DMM - the diode mode has a ->+ setting that shows volts or 0L and the audible setting 0))) which gives the beep and shows ohms on the display

OK, that probably explains the results. So in diode mode if you short the probes it shows 0 but there's no audible feature or noise in that mode?

[Hok]

Re: Panisonic 42inch TCP42S30 not working!!

I was testing across SN2 with the audible setting, and not the diode mode, this is why I assumed I had not yet found the fault(s) with the board - i was getting 0L every time, in both directions.

[Hok]

Re: Panisonic 42inch TCP42S30 not working!!

thanks for those links, I first exhausted that search before I began to work on this. Understand your doubts about my abilities.... and I respect your patience, knowing what a pain it can be for you to think in Latin when i work in dogspeak
Using a Mastech DMM - the diode mode has a ->+ setting that shows volts or 0L and the audible setting 0))) which gives the beep and shows ohms on the display

[tw2005]

Re: Panisonic 42inch TCP42S30 not working!!

http://www.moduslinkptstvboards.com/TXNSN1PKUU/

Intersting the AD revision will also work and subtitute but they charge $30 less?

http://www.moduslinkptstvboards.com/tnpa5349ad/

[tw2005]

Re: Panisonic 42inch TCP42S30 not working!!

Indicates no longer shorted which is what would have triggered the original condition. Impossible to say you've isolated the faults as there are several blown components.

What is making this difficult is knowing if you are testing the parts correctly and interpretting the meter right.

what type of meter have you got? I'm not understanding OL/reading in diode and OL/OL in audible.

[Hok]

Re: Panisonic 42inch TCP42S30 not working!!

oops. Well that was a headache I probably didn't have to live through, had i had a bit more knowledge.

Does it indicate that I have isolated the faults?

[tw2005]

Re: Panisonic 42inch TCP42S30 not working!!

sorry just posted that and it refreshed, TW - saw your post...
what happens is 0L one way and .453 volts the other, on audible i get 0L both ways

That's not short.

[Hok]

Re: Panisonic 42inch TCP42S30 not working!!

sorry just posted that and it refreshed, TW - saw your post...
what happens is 0L one way and .453 volts the other, on audible i get 0L both ways

[Hok]

Re: Panisonic 42inch TCP42S30 not working!!

Can I go through the TP points on the back of the board to isolate where the fault(s) is/are? If so, how would I go about it?

[tw2005]

Re: Panisonic 42inch TCP42S30 not working!!

So at SN2 in diode mode, what happens when you probe across the pins

[Hok]

Re: Panisonic 42inch TCP42S30 not working!!

I guess the current Panasonic Plasma in this size cost about 3.5x the cost of these boards.. Ugh i'm really hating televisions right now.

[Hok]

Re: Panisonic 42inch TCP42S30 not working!!

It's clear that I'm out of my league

lifted one leg on Q600, and board is still showing short. I have no way of testing IC502, but I doubt that it could be causing a short. I have tested all the normal components that come in the repair kits, as well as a multitude of others. Was hoping that I could find the issue on my own, but I think i'm grasping at straws at this point. These boards are hard to come by and expensive, as well...

[Hok]

Re: Panisonic 42inch TCP42S30 not working!!

Great, thanks for taking the time to help out a n00b.

R401,402,421,422 all read 7.5-8 Ohms. Have removed the corresponding igbt's thinking they were faulty - only 1 is faulty.

q451 and q441 are faulty, but the corresponding resistors both measure about 6 Ohms

Q621 and Q622 appear to be faulty - their corresponding resistors measure 115 Ohms (there are additional resistors as well, R682 and R681 that measure 10 Ohms each)

Q601 appears to be shorted, and R601 reads 1 Ohm (There is discoloration in the holes around Q601 and Q

Q661 and Q660 appear to be shorted.

have lifted both legs on all of the shorted transistors - only one left is:

Q600, which appears to be shorted. Board still showing short, cross your fingers for me on this last piece...

[Glitcher]

Re: Panisonic 42inch TCP42S30 not working!!

If this is the case, there appears to be a lot more mosFets than usual that are fried. [D642,D641,D461,D481,

Those are actually diodes. They have the same look and package as a FET but its different. I'm assuming you measured them shorted from pins 1 and 3? In that case its normal.

**Think of it as two separate diodes in the package, where pins 1 & 2 is a diode and pins 2 & 3 is another diode. And if I remember right the direction of flow would point toward pin 2.

[tw2005]

Re: Panisonic 42inch TCP42S30 not working!!

Thanks, TW. You've been very helpful in the Panasonic threads i've been through here and elsewhere. You have caught on quickly to see that I'm having knowledge issues with testing the components...
Just to recap what you've said so that we're sure I'm clear:
1) using the diode (audible) test, which measures resistance, if I get a beep across the mosfets and igbts, then the component is likely bad and should be tested out of circuit. (To prove how much of a dummy I am, I thought it was the opposite - goes to show my lack of education in electronics would not get me far..) If this is the case, there appears to be a lot more mosFets than usual that are fried. [D642,D641,D461,D481,
2) How should i test them out of circuit? I have seen 2 ways - one with mm (open gate and check waning voltage,) and one with a power supply and small load that lights up when the gate is opened.
3) on the miniscule smd resistors - It appears that all 6 of those R's give a beep, even on the 2 'good' igbt's, and the 2 'good' DG302 at Q441 and Q451 - does this mean that all 8 of those are gone?

diode mode measures voltage drop.

Constant beep is short or low resistance. short beep and a reading is not but on low resistance it will be a continuous beep. Depends on the quality of the meter. I think with mine anything below 100ohms will beep constant.

The only items I would use the buzzer on are the semiconductors, eg transistors and diodes. For the resistors go resistance and measure in cct. If they measure their value or a bit lower that would be ok. generally the resistors burn out and either go high resistance or open cct.

Sometimes if you look real close there will be burning or an exit hole where they've failed.

To keep this simple, set meter to diode, on the smd transistors place one probe on the tab and the other on each of the legs one at a time and observe. If the meter beeps constant and reads low like 0 or 0.01 etc, that's dead short, then would have to remove or lift legs to confirm in case another transistor is shorting the tested one.

On the SMD diodes, do the same, one polarity no reading, reverse probes and if good will get short beep then reading, could be 0.3 -0.7 as a guide. leg to leg though will show short as they are both the same . tab is cathode, legs are anode. again a constant beep in both directiions would indicate bad but again lift the legs to confirm.

[Hok]

Re: Panisonic 42inch TCP42S30 not working!!

Thanks, TW. You've been very helpful in the Panasonic threads i've been through here and elsewhere. You have caught on quickly to see that I'm having knowledge issues with testing the components...
Just to recap what you've said so that we're sure I'm clear:
1) using the diode (audible) test, which measures resistance, if I get a beep across the mosfets and igbts, then the component is likely bad and should be tested out of circuit. (To prove how much of a dummy I am, I thought it was the opposite - goes to show my lack of education in electronics would not get me far..) If this is the case, there appears to be a lot more mosFets than usual that are fried. [D642,D641,D461,D481,
2) How should i test them out of circuit? I have seen 2 ways - one with mm (open gate and check waning voltage,) and one with a power supply and small load that lights up when the gate is opened.
3) on the miniscule smd resistors - It appears that all 6 of those R's give a beep, even on the 2 'good' igbt's, and the 2 'good' DG302 at Q441 and Q451 - does this mean that all 8 of those are gone?

[tw2005]

Re: Panisonic 42inch TCP42S30 not working!!

easiest way to do a quick check is set the meter to diode or continuity check and probe between the legs. generally they'll go shorted across all 3. metal tab is what would be the center leg if these were through hole components.

Anything that constantly beeps is short would need to be removed or lift the legs as glitcher mentioned and confirmed bad out of cct.

No reading is normal as there is a special way needed turn the transistor on to check it but if it's not short I'd move on.

looking at some of the kits for sale, hard to tell if you'd get away with just the shorted IGBTs.

Here's the list which gives most locations, the rest would not be too hard to work out.

Q401,Q402,Q421,Q422,Q621,Q531,D401,D421,IC502,Q6??,R???,R???,R???,R???,R???

Another list from GTV watford which i would trust is for shorted SC

The kit also has 4 smd resistors, most likely gate resistor on the transistors but I'd check any in cct around that list of parts.

PARTS Q401 Q402 Q421 Q422 Q441 D401 D421
PLUS IC502 AND Q531 WILL FAIL IN 20% OF CASES

Q401 Q402 Q421 Q422 = B1JBDN000004 = GT30F131, Gate resistors R401,402,421,422 = D0GF7R5JA047, M 7.5 OHM,J, 1/3W

Q441= DG3C3020CL (DG302), gate resistor R441, D0GF5R6JA047, M 5.6 OHM,J, 1/3W

D401= B0FCCN000003 = RF1501NS3S

D421= B0FCBN000001 = RFN10NS3S

IC502 = C0ZBZ0001822 = BD8693FVM-HVTR,

Q531 = B1HFPFA00001 = CPH5524-TL-E, check R531 10ohm. R532 47k

[Hok]

Re: Panisonic 42inch TCP42S30 not working!!

will attempt to post a photo of the board, (TNPA5349)

those with no reading at all are the 2 DG302's (Q451,Q441) and 2 of the 30F131's (Q621, Q622)

Have already removed 401,402,421,422 and already I doubt whether or not I should have. Very confused so your advice is welcomed.