Re: Misbehaving Apple II+ -- Help!

[Michael J. Mahon <mjmahon@aol.com>]

"Apple2fan" <none@noone.net> wrote:
> "Michael J. Mahon" <mjmahon@aol.com> wrote in message
> 2086465967323896648.246421mjmahon-aol.com@news.giganews.com">news:2086465967323896648.246421mjmahon-aol.com@news.giganews.com...
>> "Apple2Steward" <none@none.net> wrote:
>>> 
>>> So my questions are
>>> 
>>> 1.  Can I swap in the IIe CPU to test?
>>> 2.  Are there other likely sources of failure?
>>> 3.  Are new 6502s available if that's the problem?
>>> 
>>> Suggestions would be most appreciated!
>> 
>> Ouch!
>> 
>> +5v going to 8v and +12v to 20v does not bode well for your main board or
>> your cards.
>> 
>> I'm afraid they may be too damaged to make repair practical--though it
>> never hurts to try.
>> 
>> Most diagnostic guides are based on the assumption of a single failure,
>> and
>> that seems optimistic in your case.
>> 
>> -michael  -  NadaNet 3.1:  http://home.comcast.net/~mjmahon
> 
> Thanks -
> 
> I am happy to report that the Thunderclock and the disk controller card both 
> still
> work when installed in another machine.

That's very good news. 

After replying, I realized that you had measured the supply voltages
*unloaded*.  The Apple supply, like most switching supplies, can only be
accurately measured when at least partially loaded. 

Hopefully, damaging voltages were not applied to your main board. 

-michael  -  NadaNet 3.1:  http://home.comcast.net/~mjmahon