Mac SE/30 booting but blank screen

[LeSpameur]

Hi everyone,

For the past few days, my SE/30 hasn’t been displaying anything on the screen.


I completely cleaned the motherboard with isopropyl alcohol and replaced the capacitors.


It still boots and plays the startup chime, but nothing shows on the screen. I’m fairly certain the issue is with the video circuitry, but I don’t have an oscilloscope to check each signal.


I have a Rev 2 board for parts, but it’s showing a simasimac issue due to battery leakage.

Thanks in advance for your help!

 

[djc6]

By "blank screen" do you mean there is a raster or a plain background? Or a black screen with no image at all?

I just resolved a similar on my SE/30 - maybe some of my troubleshooting steps will help: https://68kmla.org/bb/index.php?thr...king-to-no-video-does-chime-on-startup.48851/

 

[LeSpameur]

I fixed it by replacing one of the LS393 chip. It was damaged by leacking capacitors.

 

[GreenBar0n]

Nice work! What gave you the clue that it was the LS393 chip causing this? Was the chip visibly corroded?

 

[finkmac]

you can see it in the picture. it's rather corroded there. those ICs are in the direct path of the leaky lytic fluid. fairly common fault.

 

[djc6]

I fixed it by replacing one of the LS393 chip. It was damaged by leacking capacitors.

Nice! Which was broken, UG8 or UF8?

 

[LeSpameur]

Nice! Which was broken, UG8 or UF8?

UF8. I also remplaced UG8, just to be sure in the futur.