Panasonic TX-P42C2l : No Power with 4 LED Blinks

[dulipra]

Re: Panasonic TX-P42C2l : No Power with 4 LED Blinks

Hi I have a different problem with my Panasonic tx-p42s20b

SS + SC both connected = 4 Blinks
SS + SC both disconnected = 7 Blinks
SS connected + SC disconnected = 7 Blinks
SS disconnected + SC connected = 4 Blinks

Please let me know if anybody have an Idea about this

[tw2005]

Re: Panasonic TX-P42C2l : No Power with 4 LED Blinks

Hi I have a different problem with my Panasonic tx-p42s20b

SS + SC both connected = 4 Blinks
SS + SC both disconnected = 7 Blinks
SS connected + SC disconnected = 7 Blinks
SS disconnected + SC connected = 4 Blinks

Please let me know if anybody have an Idea about this

most likely shorted tnpa5105 sc board, check across the sc2 connector pins if shorted ( that's with the p2 cable disconnected)

Once that 's been confirmed you then need to check the SM board is not shorted.

5105 boards are hard to come by but it's possible to repair them.

[dulipra]

Re: Panasonic TX-P42C2l : No Power with 4 LED Blinks

most likely shorted tnpa5105 sc board, check across the sc2 connector pins if shorted ( that's with the p2 cable disconnected)

Once that 's been confirmed you then need to check the SM board is not shorted.

5105 boards are hard to come by but it's possible to repair them.

it is 6 blinks when SC fully disconnected. pins are not shorted
I connected the SC again and disconnected the SM board = 4 blinks
Now I can see burnt signs on one of the M81737FP chip on the top (see picture).
please let me know what should i do now. do you think other chips are ok or i need to replace all?

[tw2005]

Re: Panasonic TX-P42C2l : No Power with 4 LED Blinks

it is 6 blinks when SC fully disconnected. pins are not shorted
I connected the SC again and disconnected the SM board = 4 blinks
Now I can see burnt signs on one of the M81737FP chip on the top (see picture).
please let me know what should i do now. do you think other chips are ok or i need to replace all?

It has to be shorted or in the hundreds of ohms then, what resistance do you have at Sc2? the 4 blink is a P board error due to vsus being shorted or cloe enough to short. The fact that 4 blinks clears with SC isolated confirms Sc bad, other results are to be expected with what your doing.

Is it IC521 that has a hole? ( driver ic)

[tw2005]

Re: Panasonic TX-P42C2l : No Power with 4 LED Blinks

should have checked the photo, answer is , yes IC521 blown

So if you check these I expect they'l be shorted, resistor may be blown .

Q421/Q422/Q451/Q401/Q402/Q661/D482/R551/R451/IC16521

[dulipra]

Re: Panasonic TX-P42C2l : No Power with 4 LED Blinks

yes they are shorted. what you think i need to replace. I'm very new to this stuff. Really appreciate your help.

[tw2005]

Re: Panasonic TX-P42C2l : No Power with 4 LED Blinks

yes they are shorted. what you think i need to replace. I'm very new to this stuff. Really appreciate your help.

well, at least all of those. Question is do you have the gear or any soldering experience. There is a kit on ebay the only risk is if there are any parts blown not covered.

have a look at this, what I'm interested in is Ic771, ic773, q701,702, 818

start with the resistance of the output of ic771 and probe all combinations of the 3 legs of q701,702 and see if shorted

I've done the 5081 board which is similar to this

[dulipra]

Re: Panasonic TX-P42C2l : No Power with 4 LED Blinks

well, at least all of those. Question is do you have the gear or any soldering experience. There is a kit on ebay the only risk is if there are any parts blown not covered.

have a look at this, what I'm interested in is Ic771, ic773, q701,702, 818

start with the resistance of the output of ic771 and probe all combinations of the 3 legs of q701,702 and see if shorted

I've done the 5081 board which is similar to this

Thankx. I removed all the transistors that you have mentioned and they are faulty except one of RJP43F4A. I couldn't find IC16521 in this board. Is there anything that I should check?
And I orderd the repair kit. it will take 2, 3 weeks to receive.
So after fix new parts, how can I check the board before turn it on? I'm bit afraid what will happen if I have missed any.

[tw2005]

Re: Panasonic TX-P42C2l : No Power with 4 LED Blinks

Thankx. I removed all the transistors that you have mentioned and they are faulty except one of RJP43F4A. I couldn't find IC16521 in this board. Is there anything that I should check?
And I orderd the repair kit. it will take 2, 3 weeks to receive.
So after fix new parts, how can I check the board before turn it on? I'm bit afraid what will happen if I have missed any.

It's the one with a hole in it. You did not order the kit from the UK (GTV WATFORD)?

Oh, and I gave you some suggestions and a photo for other things to check.

[dulipra]

Re: Panasonic TX-P42C2l : No Power with 4 LED Blinks

Actually I ordered the IC. its from china. I didn't know about this shop before. and for the other parts I was thinking about; http://www.ohmsupplies.co.uk/epages/...roducts/KIT311

Please let me know if there is any better options.

[tw2005]

Re: Panasonic TX-P42C2l : No Power with 4 LED Blinks

which kit did you get?

[dulipra]

Re: Panasonic TX-P42C2l : No Power with 4 LED Blinks

which kit did you get?

Not the kit. I ordered the IC521- http://www.ebay.co.uk/itm/4007112635...%3AMEBIDX%3AIT

I think I have done a big mistake by ordering the IC521 separately. I didn't notice that the kit include IC as well. So now I'm going to order http://www.ebay.co.uk/itm/PANA-KIT-2...-/160884802227

[tw2005]

Re: Panasonic TX-P42C2l : No Power with 4 LED Blinks

Actually I ordered the IC. its from china. I didn't know about this shop before. and for the other parts I was thinking about; http://www.ohmsupplies.co.uk/epages/...roducts/KIT311

Please let me know if there is any better options.

the ic is already in the kit if you're talking about m81737fp (ic521)

search 160884802227 in ebay for the watford kit. it has 1 transistor and a few resistors less which may not be needed you'd have to check q660 to see if it's shorted.

the watford kit are genuine parts with pre-bent and cut legs on the transistors which makes less work and a bit dearer.

But i'd check some of those bits i mentioned and check that resistance for the 5v reg ic771. if that is not done and there is ann issue, q661 and most of the work will blow and it can then blow other parts making a second attempt hard.

with the 5081 boards ic773,q702,701,818 is critical to get right so since it's very close in design it's a smart thing to check rather than taking for granted the kit will fix it

[tw2005]

Re: Panasonic TX-P42C2l : No Power with 4 LED Blinks

you could order from china and be cheaper but it's slow to receive. I manually order from utsource or make some enquiries with watford and see what they charge to rebuild yours or there may be some others in the uk that do repairs

[dulipra]

Re: Panasonic TX-P42C2l : No Power with 4 LED Blinks

you could order from china and be cheaper but it's slow to receive. I manually order from utsource or make some enquiries with watford and see what they charge to rebuild yours or there may be some others in the uk that do repairs

Hi thanks, it is really grate. very cheap than others. do you know the resistor part no for R551, R451?

Also a capacitor on power board looks like bad (1000uf 230v). it is very hard to find a one with same figures. let me know if there any alternative replacement for that.

[tw2005]

Re: Panasonic TX-P42C2l : No Power with 4 LED Blinks

Hi thanks, it is really grate. very cheap than others. do you know the resistor part no for R551, R451?

Also a capacitor on power board looks like bad (1000uf 230v). it is very hard to find a one with same figures. let me know if there any alternative replacement for that.

If you have the service manual you can find it there. the part numbers are no use as they are not real part numbers only of help if you order from panasonic.

measure the dimensions to find the package code

R551 M 10 OHM,J,0.25W ( metal film 5% tolerance 1/4 w)
R451 M 5.6 OHM,J,0.33W (metal film 5% tolerance, 1/3w)

Unless those resistors are burnt or do not measure their value, I'd just leave them. check in cct, their value and let me know how they read

As for the cap, i'd be surprised if it's an issue. Often those large value high voltage can have a slightly domed appearance but is normal.

try this filtered search

http://uk.rs-online.com/web/c/passiv...8&m=1&aaaExp=Y


and see if you can work it out, there's a dimension column and also info on the package codes

[dulipra]

Re: Panasonic TX-P42C2l : No Power with 4 LED Blinks

Hi thanks, it is really grate. very cheap than others. do you know the resistor part no for R551, R451?

Also a capacitor on power board looks like bad (1000uf 230v). it is very hard to find a one with same figures. let me know if there any alternative replacement for that.

Again I checked after remove faulty transistors and IC521 and got following figures;

R551 - 10.8 Ohm
R451 - 6.4 Ohm
Q660 - not shorted. works like a diode among S (+) & D (-)

Also I checked the ic773,q702,701,818 and they worked like diodes.
Please let me know what you think.

Also a capacitor on power board looks like bad (1000uf 230v). it is very hard to find a one with same figures. let me know if there any alternative replacement for that.

[tw2005]

Re: Panasonic TX-P42C2l : No Power with 4 LED Blinks

Again I checked after remove faulty transistors and IC521 and got following figures;

R551 - 10.8 Ohm
R451 - 6.4 Ohm
Q660 - not shorted. works like a diode among S (+) & D (-)

Also I checked the ic773,q702,701,818 and they worked like diodes.
Please let me know what you think.

Also a capacitor on power board looks like bad (1000uf 230v). it is very hard to find a one with same figures. let me know if there any alternative replacement for that.

yeah i'm not convinced you need to worry about the cap unless you show us why.

Looking at the fact both of those are 0.8 ohms more than their true value likely due to lead resistance or your meter I would say they are fine.

can you do that resistance check on ic771 as per the photo for me. for ic773 you'd need the pinouts and check vcc - gnd but you can do that if you check ic771 as shown as that is what powers that device. When ic773 fails, often it shows dead short or only 2-3 ohms there. normal resistance is 5.7-6.1k ohms

[dulipra]

Re: Panasonic TX-P42C2l : No Power with 4 LED Blinks

yeah i'm not convinced you need to worry about the cap unless you show us why.

Looking at the fact both of those are 0.8 ohms more than their true value likely due to lead resistance or your meter I would say they are fine.

can you do that resistance check on ic771 as per the photo for me. for ic773 you'd need the pinouts and check vcc - gnd but you can do that if you check ic771 as shown as that is what powers that device. When ic773 fails, often it shows dead short or only 2-3 ohms there. normal resistance is 5.7-6.1k ohms

did you mean to remove 773 from the board? i checked without removing 773;
Out-Gnd = 9.3k
Out-Vcc = 14.9k
Vcc-Gnd = 5.74k


To check 771, I dnt know the pins . anyway I checked between pins and it gave 7.4k,1.7k,5.3k. pls let me know if i need to remove them from the board before check and IC 771 pins

[tw2005]

Re: Panasonic TX-P42C2l : No Power with 4 LED Blinks

did you mean to remove 773 from the board? i checked without removing 773;
Out-Gnd = 9.3k
Out-Vcc = 14.9k
Vcc-Gnd = 5.74k

To check 771, I dnt know the pins . anyway I checked between pins and it gave 7.4k,1.7k,5.3k. pls let me know if i need to remove them from the board before check and IC 771 pins

no need to remove anything, all in cct.

in cct is fine, as per the photo, I marked the 2 pins to check. center pin is gnd, left pin is out, right is in. you should get the same resistance between out-gnd as vcc-gnd for ic773 because it's the same points in cct.

I am confused though with 3 readings though as 1 pin is gnd, so gnd -gnd should be 0

That smd reg is a 78L05 5v 150ma I think toshiba brand.