820-2936 Flickering Video, No Audio Device in System Pref

BMarden

New member
I have 220-2936, bongs, boots, charges, green light etc, all good.

The video flickers a couple time on initial boot and when in full screen video, since its Intel HD (not ATI or NVidia) I'd like to think it may be power instability rather than GPU issue.

I replaced C167D and C167E on PP1V05_S0 (from Donor), same result.

Additional Symptoms- System preferences shows no Audio Output or Input device (Boot chime works). Some bad keys on keyboard.

I am more concerned about correcting Video flicker before worrying about Audio etc.

Any Ideas? Thanks
 
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BMarden

New member
I had a look at PP1V05_S5 on scope, it measures 1.06 and it looks like there is about 10mV of 300KHz ripple on it. I also checked PP3V3, it has no detectable ripple. Not sure if thats normal or not.

Not sure if anything else I can check, or just call it bad GPU and turn it into a donor. Any input. Thanks
 

dukefawks

Administrator
Obvious liquid damage if keyboard is bad. The audio device is probably a bad jack as usual. The video flicker is probably corrosion somewhere, could be the LCD. Check external video.
 

BMarden

New member
I checked external, same deal, same flicker.

The machine came from another shop, I don't think this original logic board for case as no liquid evidence on logic board, normal grime and dust so it hasn't been cleaned either.

I suppose a careful reflow of MCP couldn't hurt at this point.
 

BMarden

New member
My bad, PCH... I assume the video signals are generated by the PCH and the T29 is only Driver circuits? Is that correct?
 

dukefawks

Administrator
No, CPU handles most of the video processing. PCH just does converting to LVDS. As the problem is also external the CPU is most likely the issue.
 
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