Panasonic TC-50PS14 10 blinks

[Caleb]

Re: Panasonic TC-50PS14 10 blinks

Thanks TW2005 for the datasheet, I was just curious, most times I can get a good parts cross reference by googling the part number, this time it showed up way off from what I was expecting. I just wanted to let anyone down the line know not to get the wrong part by accident.

Tom would switching out the inductors make that TPNA4829 suitable? Lots of those available for about 60$

Im going to test out everything else again and I think I will wager 20$ on some parts for it.

[tw2005]

Re: Panasonic TC-50PS14 10 blinks

Thanks TW2005 for the datasheet, I was just curious, most times I can get a good parts cross reference by googling the part number, this time it showed up way off from what I was expecting. I just wanted to let anyone down the line know not to get the wrong part by accident.

Tom would switching out the inductors make that TPNA4829 suitable? Lots of those available for about 60$

Im going to test out everything else again and I think I will wager 20$ on some parts for it.

Took a lot of googling for me to find those diodes, eventually i unearthed a diagram with real part numbers which confirmed a lot of my research and identified some other stuff.

[tw2005]

Re: Panasonic TC-50PS14 10 blinks

Here's the comparison list for the 46 & 50. I'm not doing all the work so check it out for yourselves. I've highlighted the obvious ones but there's 600+ lines but i think this may be conceivable.

Surprisingly the inductors are the same both qty and value, just in different locations. Some caps need changing in value and also additional ones in vacanyt positions but only a few.

the rest looks pretty good but have not gone through every resistor etc.

Cabling and mounting also needs checking out.

This is all theory open to debate, i've never done this but good luck with it all.

I used TC-P46U1 & TC-P50U1 service manuals and parts listing.

The panel listed is - MD50F12A1J

The G10 is showing MD50F12A1J, theorectically same panel part number should mean mounts should be the same positions.

[aaronwt6]

Re: Panasonic TC-50PS14 10 blinks

After thinking this over, and over, and over; I decided to try utsource and get the 6 components that come in that repair kit. It was $22 including shipping. If they end up cooked, I'm in to the TV $47 with buying it so no big deal. If I'm lucky and that fixes the SC board, I've got a decent TV for next to nothing.

[aaronwt6]

Re: Panasonic TC-50PS14 10 blinks

And Caleb, if I do get lucky (and I don't have my hopes up), I'll let you know in case you want me to check anything else on the board. It showed 3-4 weeks though for arrival using the slow shipping.

[Caleb]

Re: Panasonic TC-50PS14 10 blinks

Im going to do some more testing and verify I dont need any other parts then I will order from utsource as well, mine ended up at 18$ including shipping. I will still have to spend another 40$ plus on buffers as well, but I didnt pay anything for the tv. I am wishing you luck while I peruse the schematic looking for more failure points. One thing I was wondering if you could tell me is the circuit readings with the other shorted fets removed? mine is reading several kohms (7+-?) Across the fets but Im assuming Im reading all the rest of the circuit, every other time Ive had bad fets they are SC of less than 10 ohms. So I think they are good but would like to verify.

[aaronwt6]

Re: Panasonic TC-50PS14 10 blinks

I need to test the buffers on mine as well. Just let me know which ones you need readings on and I'll try to check them out for you.

[Caleb]

Re: Panasonic TC-50PS14 10 blinks

I was going over the board one last time before ordering some parts and found q402 shorted as well, glad I double checked before I ordered. Q401 and q403 test ok, should I replace them as well while Ive got them out? That heat sink is a bugger to get off the board. I went through my last 1.5 ft of braid. Gotta order some more of that now too.

[tw2005]

Re: Panasonic TC-50PS14 10 blinks

I was going over the board one last time before ordering some parts and found q402 shorted as well, glad I double checked before I ordered. Q401 and q403 test ok, should I replace them as well while Ive got them out? That heat sink is a bugger to get off the board. I went through my last 1.5 ft of braid. Gotta order some more of that now too.

I don't understand why you wanted the heatsink out. have you probed any of these yet?

Q16701, Q16702, IC16773, IC16771, IC16464, IC16465

Watch out for blown out gate resistors too and smd transistors shorted.

[tw2005]

Re: Panasonic TC-50PS14 10 blinks

No problem Aaron, maybe between the two of us we can figure out the sc failure, I used this TRAINING GUIDE to isolate the sc although both my buffers are blown as well.

So far
D618 (8894) shorted and one pad blown off board
R613 (473) tests ok but also had a lifted pad
Q601 (RJK6026) tests .2 ohms across all leads
Q660 (RJK6026) tests .2 ohms across all leads
Q661 (RJP6065) tests 9.2 ohms G-C and G-E and .1 ohms C-E
L699 (471B) broke 1 lead while removing to access D618

Testing resistance across vsus to ground is now 700k, What is the likelyhood that those tiny driver transistors survived? Or do you guys think I got it all or should I continue to look for more before I order parts.

Here's the OEM specs and part number for that inductor L699 G0C471KA0167

TAIYO YUDEN , 470µH(±10%), 0.46A Inductor, radial leads.
LHLP10TB471K

If you have any dead panasonic boards around the 2009 era you'll probably find one

[Caleb]

Re: Panasonic TC-50PS14 10 blinks

Ironically enough I looked through my pile of parts boards and didnt find the proper replacement, however when I looked at the inductor I broke I could still see the wire going to the coil. I was able to epoxy in another leg and resolder the connection. It tests ok with my multimeter, will have to see if it will survive the first power up.

Of all the standard parts that seem to fail on this model, Ive only had 1 of those fets fail. The reason I pulled the heatsink is there is no way to unscrew those igbts from it on the board. Only 402 is reading SC, but 401 and 403 are the same part. I was wondering as they are all linked on the same heatsink if they were all subjected to the same surge that killed the middle one and likely to fail on first power up if not replaced. Is there some method for removing those screws without pulling the sinks?

I was wondering about those tiny transistors, can I assume they are ok if they are not shorted? or do I need to get a transistor tester now (any excuse to buy new tools)

Thanks for your input TW2005

[tw2005]

Re: Panasonic TC-50PS14 10 blinks

if a stubby screwdriver won't fit , you can get 90deg ratchet with a screwdriver bit in it or do what i did and get a pair of needle nose pliers , firmly grab the head of the screw twist and loosen. Should be able to use the fingers from there.

The IGBT's are parallelled if you go into the cct schematics. The small transistors don't always show short. the type Q701,Q702 i found do, the Q818 FETS though I could not clearly identify dead in cct and stuffed me up on my SC board.

I'm interested in those parts being checked because they tie into Q661 which youhave blown.

On my TNPA5081, if any of those are bad including the 5V reg then Q661 would blow.

[Caleb]

Re: Panasonic TC-50PS14 10 blinks

I read your above post again, and went over the board again.
Q701 reads oc
Q702 has a 7 ohm short across two leads
IC773 I cant seem to find
IC771 shorted from tab to two leads 2 ohms
IC464 and 465 read identical- lowest reading is 30 ohms on same pin sets (have to find datasheet to know what Im looking at)
Also found
Q604 shorted
Q441 shorted
D523 shorted

also get bidirectional readings on
D477
D407
D725
D648
D669
D663
D611
D160
will have to check schematic to see if there is a resistor in parallel or pull to verify

All in all that board swap is starting to sound better. This one is going to be a learning experience.

[tw2005]

Re: Panasonic TC-50PS14 10 blinks

Q701 MMBTA92 is probably ok, what meter are you using and is it auto ranging or set to what when tested?

Q702 2PD601ART,215 I expected bad

IC773 TC7SH14F(TE85L,JF) you just needed to look a little bit around Q702, right next to it. I expect this is bad and generally shorts IC771.

IC771 TA78L05F(TE12L,F), shorted on 2 leads? Need to know which as the tab and centre pin are the same connection. I'm confident IC773 is the output short. The 16V line may be shorted elsewhere or you may just have to remove this reg and test out of cct. need clarification on shorted pins?

Q604 2SJ281-TL-E remove and confirm out of cct, this part of the cct is different to my 5081 board.


IC464,465 same IC as IC773, again need clarification what pins you're checking. Pins 3(gnd), 5 (Vcc). If Vout is shorted on the reg, you'll see likewise on all 3 of these as it feeds them.

D523 D1FK60-5073 (sub RKH0160AKU), looking at the cct I'd be suspicious of the FET driver ICs as they may have been killed too especially IC521 M81707FP maybe IC501.
R509 1 ohm ERJT08J1R0V maybe blown open, R523 ERJT06J750V 75ohm I would check, heading bad towards Q441 GT45G127(dead) R531 ERJT06J100V 10ohm , Q531
CPH5524-TL-E and R441 ERJT08J5R6V 5.6ohm.

Here's the I can't find it tip. In adobe with the service manual open, use the search bar (find next in PDF) up top centre.

To find on the pcb (there's 2 sides) use for example IC773. To find in a block diagram,parts list, or schematic use the identifier prefix 16, so IC16773.

The prefix is marked on the PCB. 16 will give you SS,SC.

I would use an excel spreadsheet to try and keep a track of things.

I have a good selection of datasheets saved.

[aaronwt6]

Re: Panasonic TC-50PS14 10 blinks

I read your above post again, and went over the board again.
Q701 reads oc
Q702 has a 7 ohm short across two leads
IC773 I cant seem to find
IC771 shorted from tab to two leads 2 ohms
IC464 and 465 read identical- lowest reading is 30 ohms on same pin sets (have to find datasheet to know what Im looking at)
Also found
Q604 shorted
Q441 shorted
D523 shorted

also get bidirectional readings on
D477
D407
D725
D648
D669
D663
D611
D160
will have to check schematic to see if there is a resistor in parallel or pull to verify

All in all that board swap is starting to sound better. This one is going to be a learning experience.

I've been following along as you go here and everything you've mentioned seems to test out ok on my board. Still have my fingers crossed that I'm lucky enough to just need those 6 parts although not getting my hopes up. Seems like yours took on some serious damage.

[Caleb]

Re: Panasonic TC-50PS14 10 blinks

Tw2005, not near the board at the moment but I will check and clarify when I get back home. Im using a fluke 87v multimeter on auto-ranging to check. On ic 771 if the tab were on top the left bottom and middle were shorted, on 464 and 465 if the side with two legs were top the top left leg has 30ohms to the bottom right leg,

Ive found I really have to make sure Ive got a solid connection from the test leads to the board, Im not sure if there is a layer of oxides on the solder, but a few times I would test a component and it would test open (ok), then as I came back through to double check it would be shorted. The fluke probes are not as pointy as my other multimeter, really have to give them a good push.

Thanks for that tip on pdfs I didnt know it would do that.
Aaronwt6 do you also get bidirectional readings on those diodes? most of them are the tiny chip diodes-chances are good I will destroy some of them getting them off the board. Most are in the bottom left corner of the board.

[aaronwt6]

Re: Panasonic TC-50PS14 10 blinks

I can't seem to locate a couple of those but most seem to be in the 5-10 kohm one direction and open the other.

And wow some of those are small. You've worked a miracle if you get that board to function.

[Caleb]

Re: Panasonic TC-50PS14 10 blinks

On Ic773, Ic464 and Ic465 I get 30 ohms between vcc (5) and ground (3), And 180k between 2 and 4. On ic773 i was getting a solid short between 1 and 5, so I pulled the chip only to find they just ran the trace under the chip from 1-5. I also pulled the reg, the part tests ok, but on board with q702 removed I still am getting 30 ohms between pins 1 and 2 ( of the reg). At this point Im not sure if thats ok or constitutes yet another failed component? I pulled d523 and it also tests ok out of circuit and I have 33 ohms across the pads. I need to print out some blow ups of the schematic so I can read all the numbers and trace out all the connections. I will have to figure out how to test that fet driver as well as checking those resistors you've pointed out, after looking at the schematic some more I found all the bits thanks to that search function.

[tw2005]

Re: Panasonic TC-50PS14 10 blinks

I'm surely confused now. IC771, if you can look at the datasheet and refer to pin numbers. The centre and tab are the same so will be short , the pin on the left also short? Now is this left with the tab at the top or the ic is out of cct turned upside down or what?

As per the datasheet, 1 is Vout, 2 gnd, 3 Vin. Pin 2 to tab(gnd ) = short. If 1-2 = short then we should see short on any of those inverter ICs 3-5.

The regulator is only rated to 150ma so theorectically a 30ohm load will take it to 167ma so I'm not optimistic at this point . I only have one of those in my cct but resistance on the 5V supply to that inverter is 5.6k in cct.

[Caleb]

Re: Panasonic TC-50PS14 10 blinks

That's OK this is confusing me as well. I do have 30 ohms across VCC to ground on all those Schmidt inverters. I've got 773 pulled out of circuit, 464+465 still in circuit. On the reg I have 30 ohms between vout (1) and ground (2). So I guess one or both of those inverters are leaky I will have to pull them to find out. The reg read 5.6 k out of circuit as I recall so at least that jives with your measurements.