Restoring an iMAC G3 (M5521)

[pixel63]

Hello to everybody,
a friend of mine just gave me an iMac G3 (M5521) (slot CDROM, indigo from the 1999), asking to try a restoration.

At the moment the machine doesn't switch on at all, so I'm starting to troubleshoot the power board and the power rails.
Since now I was able to found only the Repair Manual but nothing on the schematics.

Does any of you have the schematics for the power board and/or the MLB (820-1090-A)?

Thanks in advance

 

[MacTech68]

Other than the service manual, I've not seen circuit diagrams for Logic or Analog boards for CRT based iMacs.

 

[pixel63]

That's a pity.
Nevertheless, for me it's a splendid occasion to do electronics repair.
A gorgeus, vintage iMac from 1999!
I will try to post here and on my blog the troubleshooting work as it will be going on.
Stay tuned.
...

 

[MacTech68]

You'll find the service manual will walk you through a very basic power troubleshooting with some test-points to check.

That should at least point you to a particular module.

Is the machine completely dead? No sound or lights at all ?

 

[pixel63]

Yes, dead.
I have the service manual and today I'll go through the tests you mentioned so we will see ...
I'm able to do board level repair but without the schematics it's harder and more time consuming.

 

[CooperBox]

Should be interesting to see how your trouble-shooting goes. Eventually if still no progress, head over to the PPC forum as there are not only many iMac G3 lovers there, you may also find someone offering spares you may require such as replacement Moboard etc.

PS: Just read your other posts and I believe it will be difficult - if not impossible to find anyone more knowledgeable than MacTech68 on other forums.