HELP - Bad Inverted Colors - SANYO 37" LCD TV DP37647

[kburks1230]

Hi all,

I bought this broken tv off craigslist the other day.
Any clues what could be causing the inverted images and ghosting on this tv?
T-con AS15 ic issue? or main board maybe? Any helpful insight would be appreciated.
See the attached picture.

-Ken

[budm]

Re: HELP - Bad Inverted Colors - SANYO 37" LCD TV DP37647

It does look like it has GAMMA problem.
There are more than one version of the T-CON/PANEL.
http://www.shopjimmy.com/catalogsear...ult/?q=DP37647

[tom66]

Re: HELP - Bad Inverted Colors - SANYO 37" LCD TV DP37647

Yeah, I'm going to agree it is a gamma problem. You can check the gamma voltages and either replace the IC, or whole t-con board. Gamma problem is usually only common on Chimei, Chungwha and AU Optronics panels as they tend to use AS15 ICs.

[kburks1230]

Re: HELP - Bad Inverted Colors - SANYO 37" LCD TV DP37647

How hard is it to drag solder those ic leads with a standard 25w iron?

[tom66]

Re: HELP - Bad Inverted Colors - SANYO 37" LCD TV DP37647

Difficult, you really need a temperature regulated iron, typically a minimum of $100 investment.

[kburks1230]

Re: HELP - Bad Inverted Colors - SANYO 37" LCD TV DP37647

How about the Weller WES51? Can I get onto those single pins with the standard tip?

[kburks1230]

Re: HELP - Bad Inverted Colors - SANYO 37" LCD TV DP37647

Amazon has the WES51 for $83, a board would be a little less but I do a bit of soldering on guitars and amps so it would be nice to have a better setup anyhew.

[tom66]

Re: HELP - Bad Inverted Colors - SANYO 37" LCD TV DP37647

It looks like a decent iron. You can practice on an old motherboard or piece of electronics before trying the t-con. A hot air gun is a useful tool to take the device off, you may need one of those but a cheap paint stripper can do the job fine.

[kburks1230]

Re: HELP - Bad Inverted Colors - SANYO 37" LCD TV DP37647

Status update,

I was able to desolder the AS15 chip successfully with my heat gun. I wrapped the board in foil first to keep heat off of the rest of the board. The ic is marked as follows:

AS15-F
0704BG
B6912L08

Are AS15 chips all standard or do I need to worry about those other numbers?
Where is a good place to buy this part?

Thanks guys!

[tom66]

Re: HELP - Bad Inverted Colors - SANYO 37" LCD TV DP37647

I mentioned above you should check the gamma voltages (I can help with this) before removing the IC or replacing a board. If you want to just replace the chip then I believe you have to match the last letter as well. There are many for sale on eBay.

[kburks1230]

Re: HELP - Bad Inverted Colors - SANYO 37" LCD TV DP37647

What is the procedure for checking the gamma voltages? Thanks for the help Tom, I really appreciate it.

-Ken

[tom66]

Re: HELP - Bad Inverted Colors - SANYO 37" LCD TV DP37647

It requires the IC be present on the board, you may as well swap it now as putting an old IC back on risks damage.

[kburks1230]

Re: HELP - Bad Inverted Colors - SANYO 37" LCD TV DP37647

Ok, I ordered the new IC, should be here on the 26th.