820-2936 External Video Only Works Via VGA

[brunomotter]

Hello. Got this board dead, no power. ISL6259 failure. Replaced it and R7051/52 as they were fried. Board works now. Internal video ok, external video only works with Mini DP to VGA adapter. Mini DP to HDMI does not work. Known good adapter, works on another machine. Where should I start? Never got this issue before.

 

[2informaticos]

Try another adapter.
Apple specifies third-party adapter for HDMI output.

" Thunderbolt digital video output

• Native Mini DisplayPort output
• DVI output using Mini DisplayPort to DVI Adapter (optional)
• VGA output using Mini DisplayPort to VGA Adapter (optional)
• Dual-link DVI output using Mini DisplayPort to Dual-Link DVI Adapter supports 30-inch Apple Cinema HD Display (optional)
• HDMI audio and video output using a third-party Mini DisplayPort to HDMI Adapter"

 

[brunomotter]

I tried 3 different working adapters. Also, costumer complained it wasn’t working with his own HDMI adapter before machine died. So it’s for sure not an adapter issue

 

[2informaticos]

Conversion DP to HDMI is done inside the external adapter.
Same as for VGA; you can see CRT (RGB) outputs of PCH are not connected.

Check T29DPA_HPD level, when connect HDMI monitor.