Apple Macintosh Classic M0420

[Dpj]

Hi I'm new to the forum and wondered if anyone could offer me advice or point me in the right direction. I have an old Apple Macintosh Classic M0420 which at one time I used on a daily basis. It always worked fine. When we moved it got put in the box in the loft and must have sat there for the best part of 20 years. I was having a clear out and got it down to try it out. Unfortunately the screen just showed black and white lines and it wouldn't boot up. I did some research online and saw that people washed motherboards to cure the problem of leaking capacitors. I am wary of doing this so I have cleaned the motherboard instead with isopropyl alcohol, a tooth brush and cotton buds. The lines seem less but it's still not working. Does anyone know if I should try the washing technique or is there another solution. I am not as you can properly tell a computer expert but I don't want to discard the machine when before I put it into storage it worked so well. Any thoughts much appreciated.

 

[hardon]

Hi I'm new to the forum and wondered if anyone could offer me advice or point me in the right direction. I have an old Apple Macintosh Classic M0420 which at one time I used on a daily basis. It always worked fine. When we moved it got put in the box in the loft and must have sat there for the best part of 20 years. I was having a clear out and got it down to try it out. Unfortunately the screen just showed black and white lines and it wouldn't boot up. I did some research online and saw that people washed motherboards to cure the problem of leaking capacitors. I am wary of doing this so I have cleaned the motherboard instead with isopropyl alcohol, a tooth brush and cotton buds. The lines seem less but it's still not working. Does anyone know if I should try the washing technique or is there another solution. I am not as you can properly tell a computer expert but I don't want to discard the machine when before I put it into storage it worked so well. Any thoughts much appreciated.

Hi,

The capacitors will need replacing on the motherboard and the analogue board.

It will also need cleaning and probably need new diodes and more.

If you do not feel happy doing it yourself find someone who can, maybe sell it on eBay to a collector?

Putting it back in storage with all those nasty leaky caps still in place will probably render it useless and just add to more e-waste

If it were me, I’d sell it and buy a restored model If you have no soldering skills.

Good luck

 

[Dpj]

Many thanks for your reply Hardon. I've done some basic soldering work but that work sounds more complex and probably more suited to a specialist. eBay could be the best bet as you say so I'll consider that route.
Thanks again for the answer.

 

[MacTech68]

Yes, @hardon is correct, sadly these machines are a leaky capacitor heaven or even haven.

Just the power supply (aka analog board) can be a large amount of work. Sadly, what these types of capacitors leak is corrosive and can effectively sever tracks on the logic board. Cleaning is just one part of the process and the capacitors DO require replacement.

See here as just one example of the Analog Board:

The little Classic that could(n't)

First pic is what greeted me once the rear case was removed - this black mark was the result of the rectified AC shorting to the TDA4605 - normally fed via RP14 and RP44 (220k ohm and 22k ohm resistors), so instead of about 2 volts, the poor IC got 354 volts DC to Pin 2. The bad capacitors...

forums.macrumors.com

 

[Dpj]

Many thanks for the reply. It's good to at least know what the problem is and I'll have a look at the link.

 

[Astro13]

Mine suffered the same fate, I suggest talking to Thomas of amiga of Rochester, he charges pretty decent prices, although ups has not delivered the board to him so we shall see if he can fix it.