68kMLA Classic Interface

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Mac classic help

Posted by: Challenger 1983 on 2016-12-06 08:29:51 I got a new motherboard for my Mac classic it has no battery leakage But I still get a checkerboard pattern on the screen Please help Thanks in advance

Posted by: bibilit on 2016-12-06 08:45:55 Are you sure the Analog Board is ok ? Low voltages can produce a checkerboard pattern.  Can you advise what outputs the AB is delivering (at the HD Molex cable), if those are lower than expected (around 9/10 volts for the 12 V and 3/4 volts for the 5 V one) you have got a problem there. You can try to use an hair dryer to heat the board, probably boosting voltages a bit. http://appletothecore.me/files/leaky_caps.php Analog Boards are known for leaky caps also.

Posted by: Challenger 1983 on 2016-12-06 08:50:17 Should I use the hair dryer while the computer is plugged in

Posted by: bibilit on 2016-12-06 09:04:49 of course, but check before outputs. If outputs are low, chances are heating the board on the lower right side will creep up voltages enough to get a working Classic... for a while. IIRC 8 capacitors at least should been replaced (1100 uf/16v - 2200 uf/16v- 2200 uf 35v - 450 uf/16v)

Posted by: Cory5412 on 2016-12-06 09:06:36 Moved to Compact Mac subforum.

Posted by: Challenger 1983 on 2016-12-06 10:15:17 I do not have the tools to measure voltage

Posted by: Compgeke on 2016-12-06 11:12:06 Hit up harbor freight and grab a $5 mulitmeter. For testing PSU voltages it'll work fine.

Posted by: bibilit on 2016-12-06 11:30:58 I do not have the tools to measure voltage As a collector, this  kind of tools is a must have. Hit up harbor freight and grab a $5 mulitmeter. For testing PSU voltages it'll work fine. I agree.

Posted by: Challenger 1983 on 2016-12-06 12:30:00 Can I use an ATX power supply to test

Posted by: Compgeke on 2016-12-06 13:56:04 I'm not trying to be rude, but one thing I will say is if you're asking I'd strongly advise against it. Multimeters are cheap and the first thing I'd grab before making custom stuff.

Posted by: Challenger 1983 on 2016-12-21 15:07:55

Posted by: Compgeke on 2016-12-22 11:30:53 That rust isn't a good sign, looks a lot like battery damage, it's even in the battery location on the Classic. Are you sure there's no battery damage either from a leaking battery or exploded battery? Can we get pics of both the front side of the analog board, logic board and rest of the chassis?

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