Macintosh SE/30 screen "shimmering" issue

[Will Cheyney]

Hi all. Looking for some technical advice from you all.

I have a Macintosh SE/30 that has a very minor issue with the display. It appears that when the machine is seeking data from the HD, a very faint horizontal shimmering line effect moves up and down the screen. So faint that I can't even record it to show you. There is no "worming", distortion or burn in on the display otherwise.

I doubt the majority of people would even notice it but I'm curious as to whether anyone knows what a potential issue may be.

The logic board has been recapped and I'm planning on doing the Sony PSU tomorrow incase it's a voltage regulation thing (testing the voltage on the floppy port shows small fluctuations).

Any ideas? Thanks!

 

[blusnowkitty]

If I had to guess - and it is just a guess - it's probably magnetic interference from the hard drive. I've got an IBM PS/2 Model 25, IBM's answer to the Macintosh all-in-one PC, and the hard drive in that thing does create a very slight wobble on the screen. If I unplug power to the drive, it goes away completely.

 

[Will Cheyney]

Thanks @blusnowkitty. No luck though. I've tried disconnecting the HDD power and booting from a Floppy EMU and the issue is still present.

 

[jessenator]

The logic board has been recapped and I'm planning on doing the Sony PSU tomorrow incase it's a voltage regulation thing (testing the voltage on the floppy port shows small fluctuations).

I would also look into re-capping the analog board. I had a very similar issue to what you're describing in my own SE/30. Re-caps across the board solved that little irritation for me.

 

[Will Cheyney]

I would also look into re-capping the analog board. I had a very similar issue to what you're describing in my own SE/30. Re-caps across the board solved that little irritation for me.

Fab, good to know @jessenator!