Panisonic 42inch TCP42S30 not working!!

[Hok]

Re: Panisonic 42inch TCP42S30 not working!!

I used the flowchart from the training manual that Tom uploaded to the forums. Vsus and Vda were fine, but a short was presented for P15V. Went through the flow chart on slide 56 all the way to the bottom, the results of which indicated "replace the SC board"

So my thought was if I were to put the board back in, would it be a good test to check the P15V again - perhaps the absent of a short would indicate that we have found the fault.

As for the other transistors/diodes that are still on the board, I have tacked the legs back down - I think that they do not indicate failures, but i'm happy to check again with detailed advice. I am hoping that Glitcher's experience with the same board would give me some hope that we're almost there.

Not sure if I should test the IC and the 5-pin transistor, however if you have the time to walk me through it, I'm happy to do it.

[tw2005]

Re: Panisonic 42inch TCP42S30 not working!!

i wanted to see if the P15V short was gone, but i won't do it.... (sans = without)

would you recommend ordering the 4 igbt's, or further testing these, and/or further testing the board in its current state?

Was there a P15V short? i thought Vsus was shorted.

Did you want to check the 15V rail on the SN or do you think yo have an issue elsewhere.

You could hook up the SN but leave SN2 off, that would feed 15V to the SN and I'd expect SOS7, not sure what that achieves.

well you put a number of questions up about other transistors being suspect and the 5 pin transistor which you have not come back with the results and IC502.

[Hok]

Re: Panisonic 42inch TCP42S30 not working!!

i wanted to see if the P15V short was gone, but i won't do it.... (sans = without)

would you recommend ordering the 4 igbt's, or further testing these, and/or further testing the board in its current state?

[tw2005]

Re: Panisonic 42inch TCP42S30 not working!!

quick thought - Could I put the board back in the TV and check again for the short I received (sans the 4 igbt's) that indicated SC board failure? Or would that be worthless at this point?

Don't understand (sans the 4 igbt's).

Are you suggesting putting the board in as is and turning on? Please don't.

Do you want to see if the 14 blinks is gone or what are you trying to achieve?

[tw2005]

Re: Panisonic 42inch TCP42S30 not working!!

Oh, we were coloring the Easter Eggs a bit ago....

sounds traditional, we go for the commercial grade chocolate bunnies here

[Hok]

Re: Panisonic 42inch TCP42S30 not working!!

Oh, we were coloring the Easter Eggs a bit ago....

[Hok]

Re: Panisonic 42inch TCP42S30 not working!!

quick thought - Could I put the board back in the TV and check again for the short I received (sans the 4 igbt's) that indicated SC board failure? Or would that be worthless at this point?

[tw2005]

Re: Panisonic 42inch TCP42S30 not working!!

Wife is anxious for dinner, and i'm the cook, so i'll check back in later... Thanks TW and Glitcher for your efforts

yeah i was checking your time, I thought that was where you were a while ago when you were a bit slower coming back.

best keep her happy, i'm the same when I get into something, good to take a break, keeps the mind fresh.

[tw2005]

Re: Panisonic 42inch TCP42S30 not working!!

I'm getting from all 4 of these 30f131's similar voltage readings across all three pins, (0.005 volts and down from there) looking at resistance now: 0.3 ohms, 9.5 ohms, 12.5 ohms, and 9.5 ohms from pins 1 to 3

So from tab to each of the other pins, same results. They look like they're all stuffed.

[Hok]

Re: Panisonic 42inch TCP42S30 not working!!

Wife is anxious for dinner, and i'm the cook, so i'll check back in later... Thanks TW and Glitcher for your efforts

[tw2005]

Re: Panisonic 42inch TCP42S30 not working!!

I guess I'm working on the assumption, based on Glitcher's experience, that if i'm showing voltage, then all the pieces are probably working. Problem is, I may have been too hasty in removing all 4 of these 30F131's...

Are you suggesting, that despite the data above, that I may still need to buy the resistors and diodes that seem to be fine?

more efficient to purchase and covers the lot in case we miss something but no at this stage the resistors are looking ok.

[tw2005]

Re: Panisonic 42inch TCP42S30 not working!!

R401,402,421,422 all read 7.5-8 Ohms. GOOD
Q441 reads .373 volts from the right leg to the tabGOOD
D421 reads .425 volts on both sides (from pin 1 to pin 2 and from pin 3 to pin 2)GOOD
D421 reads .373 volts on both sides (from pin 1 to pin 2 and from pin 3 to pin 2)GOOD
R531 reads about 10 ohmsGOOD
Q531 has 5 pins, and I don't know how to test it - looks like the miniscule IC'sput meter in resistance, on the side that has 3 pins pick one of the outer legs, then on the 2 pin side pick it's partner and note resistance, could be in megohms. then do same with the other end, don't worry about the centre pin
IC502 has 8 pins or so, don't know how to test it.if Q531 is ok i expect this will be too, wait and see
All of these are in the board, the only thing removed at this point are the Q401,Q402,Q421,Q422 ok, so I take it these are the 30F131 out of cct. place one probe on the tab, probe each of the other legs and note the readin
I'm getting .451 volts with the com lead at pin1 and the positive lead at pin3 at SN2... Reversed, I get 0 volts. back to this again, last time you said a reading and OL, now you say reading and 0. the cct will charge up from the probes so maybe the meter can't handle the reverse straight away

I would love to test those GT30F131's to verify that in fact one or more of them were bad. Here is the catalog that this item is listed in, with a diagram on page 59 (see image 1) of the layout.

This is my attempt to be methodical.NICE, too many variables clutters my poor ol head. once we sort this lot out you mentioned some others you thought were shorted or are you good with them now(q661 etc)

.

[Hok]

Re: Panisonic 42inch TCP42S30 not working!!

I'm getting from all 4 of these 30f131's similar voltage readings across all three pins, (0.005 volts and down from there) looking at resistance now: 0.3 ohms, 9.5 ohms, 12.5 ohms, and 9.5 ohms from pins 1 to 3

[Hok]

Re: Panisonic 42inch TCP42S30 not working!!

I guess I'm working on the assumption, based on Glitcher's experience, that if i'm showing voltage, then all the pieces are probably working. Problem is, I may have been too hasty in removing all 4 of these 30F131's...

Are you suggesting, that despite the data above, that I may still need to buy the resistors and diodes that seem to be fine?

[tw2005]

Re: Panisonic 42inch TCP42S30 not working!!

i would love to know what's wrong before I order it, so I'm game. Keep in mind, that I have four transistors off the board... (30f131's) Can test them, but broke the leg off one of them so don't think i'll be able to reuse that one.

Buying the kit may be the way to go, just not as cheap as buying only what you need.

[Hok]

Re: Panisonic 42inch TCP42S30 not working!!

R401,402,421,422 all read 7.5-8 Ohms.
Q441 reads .373 volts from the right leg to the tab
D421 reads .425 volts on both sides (from pin 1 to pin 2 and from pin 3 to pin 2)
D421 reads .373 volts on both sides (from pin 1 to pin 2 and from pin 3 to pin 2)
R531 reads about 10 ohms
Q531 has 5 pins, and I don't know how to test it - looks like the miniscule IC's
IC502 has 8 pins or so, don't know how to test it.
All of these are in the board, the only thing removed at this point are the Q401,Q402,Q421,Q422
I'm getting .451 volts with the com lead at pin1 and the positive lead at pin3 at SN2... Reversed, I get 0 volts.

I would love to test those GT30F131's to verify that in fact one or more of them were bad. Here is the catalog that this item is listed in, with a diagram on page 59 (see image 1) of the layout.

This is my attempt to be methodical.

[tw2005]

Re: Panisonic 42inch TCP42S30 not working!!

i see... well i hope it's that easy, as it stands i've got 2x DG302's and 6x 30F131's disconnected from the board. Guess I oughtta make sure i need them before I order them...

I do get a voltage reading from 2 of the 30F131's when they're connected, but not when they're disconnected. Same with the 2 DG302's. Funny, because I believe I was told to check resistance on those, which I thought was measured by Ohms, so I was on the wrong setting perhaps?

Ok, the 2 that give no reading out of cct (OL i assume) should be ok. These fail dead short across all 3 pins usually.

Measuring resistance is fine if you know what you're looking for which is a dead short or 0 ohms.

So it sounds like the DG302 are also fine. I'll find a video which shows how to test them out of cct in diode which involves switching the transistor on otherwise you see no reading in diode.

[Hok]

Re: Panisonic 42inch TCP42S30 not working!!

i would love to know what's wrong before I order it, so I'm game. Keep in mind, that I have four transistors off the board... (30f131's) Can test them, but broke the leg off one of them so don't think i'll be able to reuse that one.

[tw2005]

Re: Panisonic 42inch TCP42S30 not working!!

I'd like you to go back to all the transistors and diodes again and see if we can be methodical and clear about the results.

What do you think? Or just buy the kit and take a gamble?

[Hok]

Re: Panisonic 42inch TCP42S30 not working!!

i see... well i hope it's that easy, as it stands i've got 2x DG302's and 6x 30F131's disconnected from the board. Guess I oughtta make sure i need them before I order them...

I do get a voltage reading from 2 of the 30F131's when they're connected, but not when they're disconnected. Same with the 2 DG302's. Funny, because I believe I was told to check resistance on those, which I thought was measured by Ohms, so I was on the wrong setting perhaps?