Drumroll please.....
Repaced UE8 fixed it!! Thank you all so much for your help! This was next level repair stuff for somebody who's just done a few recaps in the past.
I see what you mean. I cleaned it off, but yeah, that was still black corrosion. It never endsThe pad does have continuity to UC7 pin2 (VID0).
I will double check. It does seem to boot fine and has sound. Just video problems.
I double checked every pin on UD8, UE8, UF8 and UG8... they all check out with no broken traces to destinations.
My next step is to replace UE8 and possibly other U*8 chips. Replacements should be here tomorrow.
Thanks. I've checked all of the pins to ground, +5 and PAL chips. All of those are good.
The pins that are Vid(*) are not clear to
me. I'm new to schematics so I'm not sure where those ones are going. It looks like they are all connected on the schematic but with small circles?
When I connected UE8 pin13 to the neighboring pins 12 or 14, the screen lit up, but it was a mess...I could roughly make out what would be a flashing disk icon and cursor though..and I could move the cursor. I'll upload a picture when I get home.
Finally got a logic board connector extension, so I was able to play around with UE8 live... upon testing some of the voltages with a multimeter, the video came to life when I accidentally touched pin 13 to 12 (or14)..... although it was garbled, I could make out the flashing disk icon...and the...
I found something suspicious in my ROM socket (see photo). the board chimes and boots fine but I get no video at all - total blackout. I've been going through potential issues in the video circuit. Is it possible that this is the cause?