Hitachi Buffer IC replacement

[Glitcher]

Hey I got a P50S601 Hitachi that I found the lower buffer board to be bad. Unplugging the lower board, the top half of the screen shows perfectly.

Buffer board model: ND60200-0048

There are 8 Buffer ICs, how would I know which IC's are bad and need replacing?

[mmartell]

Re: Hitachi Buffer IC replacement

I would expect a short is a short is a short so the Samsung buffer board test would probably work. Don't have a link to it but search here for hp-t5054 and you will find.

[Ltank]

Re: Hitachi Buffer IC replacement

Are there any burnt or discolored parts on the board? Here is a link on testing buffer boards that might help.
http://blog.coppelltvrepair.com/2010...es-in.html?m=1

Try a search function on this site for buffer boards There is alot of highly skilled and knowledgeable techs on this site. I stopped going to other sites. They just don't compare to this one. I have bought E-books fro Young and Morrow that are very good too but this is the best site. Period

[freakaftr8]

Re: Hitachi Buffer IC replacement

These usually burn a hole in the IC. whichever IC is blown you gotta replace the next one in series if the first IC is blown for example replace the third one down and the last one like 1 3 and 5 or 2 4 and 6.

On these buffer boards if one blows it likes to damage your next one its series for some reason

[Glitcher]

Re: Hitachi Buffer IC replacement

There are no burnt holes on any of the ICs, but I did the buffer test similar to the Samsung buffers and there is definitely a short. But it doesn't show me which IC is bad.

I've been reading around the site and on google and it said that by measuring the capacitors next to the chip if it reads shorted then its bad (It didn't said exactly how to measure or where...). By I just probed around and notice there might be 4 chips that seem bad. HOWEVER I feel like the chips seem to be paired in two in parallel, so it may be just two chips that are bad, but im not certain.

Each chip is $16, so itll cost about 60$ to replace all four. Theres a service on ebay offering to repair the board for $60 so I guess that could be less work for me, BUT I don't trust it as much.

If it is just two chips I can save $30 by fixing it myself.

[mmartell]

Re: Hitachi Buffer IC replacement

Are the traces not visible ? You should be able to check the output pins for short against ground at the input connector and trace the pins back from the ouput connector to the faulty ic.

[Glitcher]

Re: Hitachi Buffer IC replacement

But the chips may be in parallel, it wouldn't tell me which of the two are bad?

[tom66]

Re: Hitachi Buffer IC replacement

No, each chip only drives a specific part of the panel. You could also try applying current to the board (low level) and see what gets hot.

[Glitcher]

Re: Hitachi Buffer IC replacement

How do I apply low current into the board?

I'm not sure if the test I did even confirms. I just measured around and looked for any differences comparing to the working upper buffer board. I found that measuring across the caps shown next to the relative chip, that four of them showed shorted.

[tom66]

Re: Hitachi Buffer IC replacement

With your other buffer, look at the where the VSCAN voltage is, between the large thick traces and the slightly smaller one. You can measure it on a meter, should be around 140V.