Panasonic TH-42PZ77U SC board repair 7 blinks

[TomKal]

Re: Panasonic TH-42PZ77U SC board repair 7 blinks

My neighbour put out her dead 42pz700u with a "free to anyone who thinks they can fix it" sign on it, and thanks to this forum, I have identified a shorted 5N2307.

Just waiting to get a replacement, but I'll also want to update the firmware as it sounds like they've tweaked it somehow to reduce the strain on these components.

I have only found http://www2.panasonic.com/webapp/wcs...PRD_CNT_007552

which appears to be a tuner firmware. Is this the one I'm looking for?

Thanks
Tom

[TomKal]

Re: Panasonic TH-42PZ77U SC board repair 7 blinks

I found the firmware for the 42pz77u attached in another thread and it turns out that it's the same as the one in the link I found above (same file hash).

[Rockguy]

Re: Panasonic TH-42PZ77U SC board repair 7 blinks

I looked around for it and never could find it

[TomKal]

Re: Panasonic TH-42PZ77U SC board repair 7 blinks

Picking up a new 5n2307 on the weekend, but I've yet been able to detach the old shorted one. So I'm wondering if I can just install over top with a small piece of wire to bridge the drain tab.

Obviously I'd make sure there's no contact with the legs of the old one, but other than perhaps heat dissipation issues and ugliness, are there any other concerns with this idea?


And Rockguy, what I meant to say in my last post was that the previously posted "fixed" firmware is the same as the one at the link I posted, so I believe that is the one we want. Once I've installed the new 5n2307, I'll update and check to see what version numbers are reported.

[Shinju]

Re: Panasonic TH-42PZ77U SC board repair 7 blinks

sweet, I got a 700u on the table now.

[Rockguy]

Re: Panasonic TH-42PZ77U SC board repair 7 blinks

Picking up a new 5n2307 on the weekend, but I've yet been able to detach the old shorted one. So I'm wondering if I can just install over top with a small piece of wire to bridge the drain tab.

Obviously I'd make sure there's no contact with the legs of the old one, but other than perhaps heat dissipation issues and ugliness, are there any other concerns with this idea?


And Rockguy, what I meant to say in my last post was that the previously posted "fixed" firmware is the same as the one at the link I posted, so I believe that is the one we want. Once I've installed the new 5n2307, I'll update and check to see what version numbers are reported.

Those things are a pain to get off without tearing anything up. Interesting idea you have about going over it. I'll be interested to see what comes of that.

[TomKal]

Re: Panasonic TH-42PZ77U SC board repair 7 blinks

Ahrg!

It was working for a short test, but in my haste to put everything back together, it looks like I used a wrong screw that goes into the plate on the back of a bridge rectifier on the power board. The screw was just long enough to snap the part it in half, giving me 10 blinks now.

The part number is D6SBN 20 and unfortunately, the repair shop that happened to carry 5n2307s has none of these.

They said they had other bridge rectifiers rated at 200v 6A, but is this something that's interchangeable? An eBay seller has a D6SBN 20, but should I wait the extra week or two for the exact part?

[SeanS]

Re: Panasonic TH-42PZ77U SC board repair 7 blinks

Using the thread below and the attached .pdf for troubleshooting 7 blinks, I've determined that it appears that I need to either repair or replace my SC board. I would like to try to repair this board if possible.

https://www.badcaps.net/forum/showthread.php?t=21700

With everything connected, the screen flashes briefly at startup and then the LED blinks 7 times. With the SU and SD disconnected, the LED blinks 6 times once, then 7 times over and over. With the SU connected and the SD disconnected, the top of the screen flashes and the LED blinks 6 times once, then 7 times over and over. With the SD connected and the SU disconnected, the bottom of the screen flashes and the LED blinks 6 times once, then 7 times over and over. With SC2 and SC20 disconnected the unit powers on and off with the remote. According to the attached .pdf file, this means the SC board is at fault.

What do I do now?

Where did you find that manual? was there one for 6 flashes? I have a problem with 6 flashes...

[TomKal]

Re: Panasonic TH-42PZ77U SC board repair 7 blinks

Got my bridge rectifier and TV is up and running. Actually using it now to type this up as it's doubling as my new computer monitor.

And that link I listed above is a newer firmware than I had. It is now 1.92 and also listed the word "peak" in the name which I might assume refers to some sort of peak limiting.

Anyway, only thing left to troubleshoot is a faint blue box in the middle of the screen when I have a white background. Looks like burn in. Can't complain for an almost free TV.

Thanks for the info on this thread!

Tom

[SeanS]

Re: Panasonic TH-42PZ77U SC board repair 7 blinks

hey all...I have only basic electrical knowledge so testing FET's is completely new to me. I recall seeing a post about testing pins and tabs as if they were numbered 1,2, and 3 but I have not refound it...and I would not know what I am looking for or be able to interpret the results. I really want to try to do this and tackle the replacement if one is needed but without guidance, I am lost. Would anyone be willing to walk me through this?
Panasonic TH-42PZ77U

[Rockguy]

Re: Panasonic TH-42PZ77U SC board repair 7 blinks

I'm not an expert but, I got mine going. Here is one thread. https://www.badcaps.net/forum/showthread.php?t=43470 In my first post in that thread, there is a link to another helpful thread. Start by doing the test without lifting any legs. Set your meter in diode mode. There are pictures that show you how to test. Here is another helpful thread. Learn from my mistakes.

You may want to start your own thread so the experts here can help you.

[radar2000]

Re: Panasonic TH-42PZ77U SC board repair 7 blinks

Since I have so little experience doing this, I decided to test all seven with the red on the lifted leg and the black on base. In this configuration I got
1=541
2=541
3=013
4=541
5=541
6=290
7=290

Hi everyone.

First time poster here.

I too have a Panasonic TH-42Z77U that has give me the 7 blinks. The TV is around 9 years old.

I have followed online and have also confirmed that the SC board is the issue.

Question regarding the FET's that you have tested... Is it necessary to have the one FET leg up, or can I test it with it still soldered in?

Apologies if this is a dumb question, but this is the first time that I've used a dmm... I'm a little green when it comes to this.

Any help/recommendations would greatly be appreciated.

I really loved my plasma TV and would hate to throw this out if there is a cost effective way of fixing it.

Cheers!

[Rockguy]

Re: Panasonic TH-42PZ77U SC board repair 7 blinks

Hi everyone.

First time poster here.

I too have a Panasonic TH-42Z77U that has give me the 7 blinks. The TV is around 9 years old.

I have followed online and have also confirmed that the SC board is the issue.

Question regarding the FET's that you have tested... Is it necessary to have the one FET leg up, or can I test it with it still soldered in?

Apologies if this is a dumb question, but this is the first time that I've used a dmm... I'm a little green when it comes to this.

Any help/recommendations would greatly be appreciated.

I really loved my plasma TV and would hate to throw this out if there is a cost effective way of fixing it.

Cheers!

The measurements I took were with zero legs up

[radar2000]

Re: Panasonic TH-42PZ77U SC board repair 7 blinks

The measurements I took were with zero legs up

Thanks Rockguy.

I'll give this a try and will post my results.

Cheers!

[radar2000]

Re: Panasonic TH-42PZ77U SC board repair 7 blinks

Now to find someone in Canada (GTA area) who sells these FET's (B1DFKM000002).

Anyone know where to order these online? I've only been able to find someone in Spain / France who are selling these online.

Cheers!

[radar2000]

Re: Panasonic TH-42PZ77U SC board repair 7 blinks

Ok, just completed a diode test with legs in test right leg and left leg.

Row Q641 to Q645 : RL = 043 LL = 764
Row Q695 to Q696 : RL = 495 LL = 1.460

Other side

Row Q648 to Q654 : RL = 477 LL = 1.306
Row Q622 to Q626 : RL = 393 LL = 1.386

Q601 : RL = 541 LL = 2.748

Based on these readings is it safe to assume that Row Q641 to Q645 are the bad FETs?

Your feedback is appreciated.

Cheers!

[radar2000]

Re: Panasonic TH-42PZ77U SC board repair 7 blinks

Ok, just completed a diode test with legs in test right leg and left leg.

Row Q641 to Q645 : RL = 043 LL = 764
Row Q695 to Q696 : RL = 495 LL = 1.460

Other side

Row Q648 to Q654 : RL = 477 LL = 1.306
Row Q622 to Q626 : RL = 393 LL = 1.386

Q601 : RL = 541 LL = 2.748

Based on these readings is it safe to assume that Row Q641 to Q645 are the bad FETs?

Your feedback is appreciated.

Cheers!

Hi everyone.

Any thoughts on the above? I would appreciate your feedback on which of these FET's appear to be gone, so that I can place an order.

Cheers!

[Moreno83]

Re: Panasonic TH-42PZ77U SC board repair 7 blinks

Just measure in diode mode on the outer legs of the fets. ( Q ).

If it beeps its shorted.

[radar2000]

Re: Panasonic TH-42PZ77U SC board repair 7 blinks

Hi everyone.

Apologies for resurrecting this thread.

After several months, I decided to fix my SC board by replacing the needed FET's...she's alive!!!

Now the only problem I'm having is finding the most up to date firmware so that I can update my TV.

Can someone please point me in that direction or can someone email the file? I'll PM you my email address.

Cheers!

[ruggb]

Re: Panasonic TH-42PZ77U SC board repair 7 blinks

radar2000 = did you ever find a f/w update?
the one I have is 2.09
I thought I had 2.12 but it showed as 2.09 when I went to upgrade it'

My bd problem is intermittent. Right now it appears permanent. Previously, I would unplug the tv for a few minutes, then reconnect and it would come on till the next time I shut it off, maybe, maybe not. There are no shorts on any FET groups. I guess it is possible a FET is breaking down under power, but I expect that it would have become permanent by now. With SC20 disconnected, I get sound, no blinks, and no picture.
I have not removed the SD and SU boards but I did disconnect SC45 and SC46. I don't know if that is sufficient to isolate those boards, but it did not eliminate the blinks with SC20 and SC2 connected.
I guess I need to disconnect the SD/SU boards unless someone knows if they are isolated with SC45/46 disconnected.
Does anyone have any ideas RE a control ckt device failure? A schematic or other diagram of the control ckt?