Philips 50PF9431D/37 - 12 VDC loaded by SSB

[NFISH]

Hi everyone!

I have a Philips 50PF9431D/37 (free from my brother) with the low 12 VDC error. This problem is very similar to the one PlainBill had back in February of this year.

I have isolated the problem to the SSB...The 12 volt supply is around 5 to 6 volts for a few seconds during the initial power check which is then followed by the error/protection mode. The supply is at 12 volts and stays on whenever 1M46 is disconnected (12 volt connection to SSB from power supply).

I don't have a schematic and WOW components just keep getting smaller on these things. I can pick-up a new board for around $100 dollars but I'm a poor college student with two weeks before the next semester starts. So if I can fix it and have a little fun at the same time that would be great!

Does anyone have a schematic of this board? A lot of my test equipment is in storage but I can do some basic troubleshooting.

Thanks in advance for the help. - Norm

[NFISH]

Re: Philips 50PF9431D/37 - 12 VDC loaded by SSB

By the way... the SSB P/N is 310432845251.

[PlainBill]

Re: Philips 50PF9431D/37 - 12 VDC loaded by SSB

It would have helped if you had appended to the earlier thread - that had the chassis number.

You have to do a little detective work to locate the service manual. There are files which cross reference model numbers to chassis number. The service manuals are listed by manual number on scribd.com.

Google 21281939-Philips-BJ2-4UPA. You will have to register, but it's a free download.

Pay particular attention to sections 5 and 9. The information at the top of the second column of page 38 is particularly important. The parts are available from Digikey. When ordering the parts also order a ChipQuik kit and some solder wick.

PlainBill

[PlainBill]

Re: Philips 50PF9431D/37 - 12 VDC loaded by SSB

Oops, I almost forgot. Use the IC numbers in the Bill of Materials, not the ones in the schematic. They are upgraded parts; the schematic was not revised.

PlainBill

[NFISH]

Re: Philips 50PF9431D/37 - 12 VDC loaded by SSB

Thanks for the help PlainBill. Sorry I didn't think about the chasis number/append issue.

I'll keep you posted on how things go.

-Norm

[PlainBill]

Re: Philips 50PF9431D/37 - 12 VDC loaded by SSB

Thanks for the help PlainBill. Sorry I didn't think about the chasis number/append issue.

I'll keep you posted on how things go.

-Norm

I looked through the schematic again. The passage in the service manual specifies all the parts - one IC and two dual mos switches. It's a relatively easy task for someone with SMT experience, but definitely NOT for someone without it. Other than having to remove one part (inductor?) to get access to one IC it was fairly easy.

PlainBill

[NFISH]

Re: Philips 50PF9431D/37 - 12 VDC loaded by SSB

Well, the fun is over...

I gave-up on looking for the IC's after finding the mosfets with almost a 30 day lead time and the a minimum 2500 piece order for the other. I finally just bought a used SSB for $79 on Ebay. I had to set the option codes (so that it used my 50" screen instead of making it 42") and update the user software section. The only minor issue is that the values for the original TV are still stored (serial number, hours, etc.). I'm assuming that these are stored in partition 0 which I could clear/install. It's working fine so why take any chances on crashing it and locking-up the board?

Thanks for all of the help. This was fun even if I didn't get to repair it at the component level.