Badcaps.net Forum
Go Back   Badcaps Forums > Troubleshooting Hardware & Devices and Electronics Theory > Troubleshooting Computer Displays
Register FAQ Calendar Search Today's Posts Mark Forums Read

 
Thread Tools Display Modes
Old 01-13-2019, 03:39 PM   #1
maldata
New Member
 
Join Date: Jan 2019
City & State: IL
My Country: USA
I'm a: Knowledge Seeker
Posts: 3
Default Old Macintosh monitor shows doubles?

Hi all,

I'm having trouble verbalizing what's happening on screen, so I'll post a picture instead: https://imgur.com/a/prN5nk4

The screen kind of has bands where things are duplicated... you can see the cursor has a nearby clone, and the bar at the top is all messed up, and the icons on the right as well.

This is a Macintosh SE/30 from 1988. It still boots up, and it seems to still work just fine. As far as I can tell, the monitor is the only problem. I'd like to fix it, but since I can't define the problem, I can't google for a solution. I'm also having trouble finding any information about the monitor hardware itself. Seems like a safe bet that it's a CRT, but that's about all I can say.

If you have any ideas about what the problem might be, or even what I should search for, I'd love some help. Thanks!
maldata is offline   Reply With Quote
Old 01-13-2019, 03:49 PM   #2
stj
Great Sage 齊天大聖
 
stj's Avatar
 
Join Date: Dec 2009
City & State: Europe
My Country: some shithole run by Israeli agents
I'm a: Professional Tech
Posts: 21,572
Default Re: Old Macintosh monitor shows doubles?

if it's jumping around then it's the monitoor vsync circuit,
if it's stable then i suspect the motherboard has a fault in the vram addressing.

do you know the refresh rate of the signal on that mac? 25KHz??
stj is offline   Reply With Quote
Old 01-13-2019, 05:59 PM   #3
maldata
New Member
 
Join Date: Jan 2019
City & State: IL
My Country: USA
I'm a: Knowledge Seeker
Posts: 3
Default Re: Old Macintosh monitor shows doubles?

Quote:
Originally Posted by stj
if it's jumping around then it's the monitoor vsync circuit,
if it's stable then i suspect the motherboard has a fault in the vram addressing.
It's stable, there's no jitter in it at all.

Quote:
Originally Posted by stj
do you know the refresh rate of the signal on that mac? 25KHz??
Nope. I don't really know anything about it, I haven't opened it up yet. Do you think this would be documented somewhere? If not, is there another way to find out?

Thanks!
maldata is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump



Badcaps.net Technical Forums 2003 - 2019
Powered by vBulletin ®
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
All times are GMT -6. The time now is 07:46 AM.
Did you find this forum helpful?