No video on SE/30

[joethezombie]

I was given a non working SE/30 logic board. I put it in my working SE/30, and nothing happened when I turned it on. So, I washed the board and recapped everything but the axials. Now when I put it in, I hear good startup chimes, and the hdd kicks up, and the the drive indicator flashes like everything is working, but the screen remains completely blank. I'm guessing I have some trace damage. I downloaded a schematic and will go continuity hunting, but am looking for any insight on where the problem might be.

 

[SlateBlue]

Check that your screen brightness is turned up.

 

[joethezombie]

Yeah, I twisted the brightness knob full stop both directions. My good logic board shows video, so it's definitely something on the bad board.

 

[techknight]

a bad UE8 can cause this. 

 

[bibilit]

I will trust Technight a 100% had a similar problem and UE8 was bad:

https://68kmla.org/forums/index.php?/topic/28003-mac-se30-screen-too-bright-with-scan-lines/

Mine had bright lines, but UE8 can show a blank screen also.

 

[joethezombie]

Working on the continuity testing right now.  In case of UE8 replacement, has TI SN74LS166AD been proven a working replacement?