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Macintosh Classic II - Display Issue. Video Output With Corrupted Image

Hi everyone,

I’ve been lent a Macintosh Classic II that seems to have had very little use. I’m in Spain, where the mains voltage is 230 V. It probably has the typical capacitor problem, I assume. When it powers on, it doesn’t manage to show an image — I’m attaching a photo of how it looks.

I opened it and cleaned it thoroughly, and surprisingly it didn’t have much dust. I still haven’t removed the socketed chips or the memory modules to clean them properly — I’ll do that soon.

You can see a video of it powering on at this link: https://streamable.com/h1w9ef.

The photo shows how it was starting up before the first cleaning, and the video shows how it starts up now.

I’d like to know where to start.

I suppose the first step is to replace all the capacitors, although I don’t know if there’s anything specific to keep in mind with this model.

Do you know if it’s necessary to do any kind of repair on the CRT?


I appreciate any advice. Thank you very much.

Jorge.
 

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This is typical from bad caps and low voltage.
Check for the 5 volt rail at the HD Molex.

Don’t much you can do until caps have not been removed.
 
welcome Jorge,

The Classic/Classic II as you will discover from searching here was a very budget Apple design and will need recapping of both the analogue board and motherboard combined, with a deep clean of everything in the process. After this, pay some attention also to the optoisolator CNY17 and power control IC TDA4605 which often fail from cap leakage/age
 
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