Working SE/30 with really strange video

[d3jsp]

The video is bad but other than that everything works! The board itself looks fine and I've swapped the video ROM with a known working se/30 with the same result.

 

[finkmac]

this looks to me like one of the video memory dram isn't getting anything written to it somehow.

i wonder what it would look like if you swapped the 41264s around...


also wait a minute are those the original capacitors?? if they are you gotta remove them, clean up the areas around the old caps, and install new ones...

 

[shirsch]

Note the green stuff sprouting from the vias between UE8 and the SMD cap.

 

[ObeyDaleks]

I would recap it first before trying anything else. Those caps look ripe. Whenever I recap, I check the surrounding traces and vias and repair as needed.

 

[s_pupp]

How do you take care of the green stuff rising from the vias?

Is it possible to repair green leads on affected IC’s that are difficult to find replacements for?

 

[shirsch]

As others mentioned, the first step is removing and replacing all the SMD caps. Everyone has their own approach to cleaning up the corrosion. I usually dab the area with white vinegar (both sides of the board if the crud appears on the bottom) and let it bubble away to neutralize any remaining alkaline residue. Wash with distilled water afterward and let the board dry for at least 24 hours. Then take a Q-Tip and 95% IPA and see how much scaling you can remove with light scrubbing. If any of the chip legs have been eaten it can be very hard to see. I don't think any of the logic chips in the row with UE8 are particularly hard to find. Best bet is to remove UE8, clean thoroughly underneath and solder in a new one.

 

[d3jsp]

Did a full recap and checked traces and it's still the same. Didn't think it was a caps issue. I suspect @finkmac is right and it's one of those 41264 chips. Going to try to replace them

 

[d3jsp]

Traces from UE8 to V(0) - V(7) look fine. Both 41264 chips also have good traces to VCC and ground. Can anyone tell if this is an issue with UC6 or UC7 from the screens above?

 

[d3jsp]

Actually, this can't be an issue with D(24) - D(31) right?

 

[d3jsp]

Fixed!! Turns out it was a break from A(11) to the video rom. Not sure how but the board looked perfect around both areas