Macintosh 128k Chimes but no Video - Not analog board

[cadenya]

I have a Mac 128k board (later revision) that chimes but has no screen. I’ve confirmed this isn’t an analog board issue with another working board. What could be the issue? I’ve seen some people say the RAM muxes, how do I test for that? Where even are those? Not sure what to do here. The board did have some corrosion on chips when I got it, and after an alcohol wash still has no video.

 

[imactheknife]

I know this is silly, did you check brightness knob?? Also, reflow all joints on flyback and power connectors on analog.

 

[joshc]

I know this is silly, did you check brightness knob?? Also, reflow all joints on flyback and power connectors on analog.

OP said they already tried with a known working analog board.

What sort of physical condition is the CRT in? Is the neck intact?

 

[imactheknife]

if needed i do have a spare crt. Just pulled from unit with non working analog. Sorry, didn’t read whole post before answering before hand on firstly comment

 

[cadenya]

Sorry, what I meant was I tedted another working logic board in the case and it worked. It’s a logic board issue.

 

[joshc]

Reflow the power connector pins on the logic board

 

[cadenya]

Reflow the power connector pins on the logic board

Sadly that didn’t fix the issue.