Weird noises and no display - Classic & Classic II

[SilentSausage93]

Hi All,

Picked up two dead Mac Classics for $100, I E joy fixing older computers but these will be my first Mac's.

Both have the same faults:

- When the power switch is flicked, fans spin up and so do hardrives

- Speakers emit strange noises

- No display

- No startup chime

Here is a demo:  https://drive.google.com/file/d/1ztW4vi8SSR5rWdApOwaSm_xCXjPR1e7n/view?usp=drivesdk

Where would be a good place to start? From going through threads for the past hour I'm guessing it's going to be recapping? I'm in Australia so I'm guessing it will be an international board - is there a part list for recapping the Logic and Analogue board?

....now I'm off to buy an extra long T15 Screwdriver

 

[techknight]

Welp as said a million times, and you had likely found, these things need a full restoration before they even BEGIN to work. 

Your other problem is going to be the battery. the majority of the Classic models had the maxell batteries which are called the Red Bomb. They explode, leak all over the board, and basically render the unit beyond repair. 

So you need to get these things apart fast. Once you know the battery hasnt leaked or destroyed anything, then you can begin to inspect the PCB for damage. The PCBs need washed and all caps replaced. 

 

[SilentSausage93]

Thanks for confirmation. Caps have been ordered. Batteries are intact and show no signs of leakage. 

Would you be able to point me in the right direction on cleaning the PCB Correctly? 

Thanks for your help .

 

[techknight]

First thing I would do is remove the batteries from the units and toss them. Wouldn't worry about putting new ones in unless you have to have the time. 

As far as cleaning, Me personally I use ultrasonic baths. But there are others in here that use other methods, I would search around. 

 

[cfriberg]

Be gentle and controlled but firm with every step of the repair.  Disconnect and remove the logic board.  Remove all the ROM chips and RAM boards.  Look up ROM chip pullers on the net and just make them yourself with a pair of old tweezers to remove the ROM chips. They are stubborn and have fragile pins.  Keeping track of the order and orientation they go in.  REMOVE THE BATTERY like technight said.  Order a new one on amazon.com, super cheap.  Coat the board in alcohol and gently scrub with a toothbrush.  Stick it in the dishwasher and do a "short rinse"  cycle on it.  Dry it as best you can and let it set out to dry while you wait for that new battery to arrive.  Reinstall all the ROM and RAM and new battery and plug it all back in and try and boot it up.  If it works, Hooray!

Then get some new tantalum capacitors (little yellow rectangle guys) on digikey.com and match or exceed the voltage and capacitance ratings.  The smaller caps are "package/case/manufacterer" size A and the bigger ones are size C.  I used two soldering irons at the same time to patiently remove both capacitor solder points at the same time.  Then clean the solder pads with alcohol on qtips and solder new capacitors on with the positive and negative like they look on the bottom side of the board (positive is the black strip side of capacitor I think).  I did like two or three capacitors at a time and plugged it all back in to make sure it's still working in case you mess up you don't have to go back and recheck every single capacitor.