Another Colecovision video issue thread

[Ramses]

My AV modded (LM318) Colecovision is on the fritz. I'm guessing it's the VRAM. It started having problems after a power outage a while back which makes the power switch seem like an unlikely culprit. It began with small little graphical glitches here are there and progressively got worse. I tested the power supply and the readings seemed good. Audio works fine along with the inputs. I've attached a sample screen of Donkey Kong.

 

Given this info am I correct in assuming that it's probably a VRAM issue? What should be my next steps? I've never had any luck with desoldering my Colecovision or Atari 800XL in the past so I'll need to find someone who would be able to fix it.

Edited August 9, 2018 by Ramses

[Taijigamer]

Use this page from the service manual for tips http://www.colecovisionzone.com/photos/coleco/colecovision%20tech4.pdf. Check for activity from the VRAM pins on the TMS9928 (U9). Most likely VRAM as you said or a bad 9928.

Edited August 9, 2018 by Taijigamer