Re: Apple II power supply

[Stephen Shaw <xstephenx@apple2.org.za>]

On 30 Dec 2001 13:40:24 GMT, Quadrajet1 wrote:

>>> IIRC, the usual repair for these is to replace all the electrolytic
>>> capacitors.  I think the one at "C2" goes bad the most often, but
>>> that's hazy memory.
>>
>>No that is C7 Matthew. C7 Matthew. Hold out your hand so that I can smack it
>>with a ruler Matthew. Then go and stand in the corner for the rest of the day
>>Matthew. When you go home today Matthew you will write out a hundred times
"C7
>>is faulty." And, no, you cannot use your word processor!
>
>   And the bad C7 only applies to Astec power supplies and not the crappy
> DynaComp power supplies.  Ahh, fixed many a power supply in my day.
> Problem with C7 is there is a high temp resistor sitting right next to it,
> and it bakes the cap into submission over time.  Whenever I replaced the
> cap, Iwould use some spaghetti tubing and move the cap away from the heat
> producer.
>
> Raymond

You are right Raymond. Apologies I've got so used to Astecs I'd even forgotten
DynaComps existed. However, rather use a 105 degree Centigrade rated cap for
C7.
I've done quite a few Astecs and never had one back yet. Do not go over a 25
volt rating for the cap otherwise it will not polarise due to insufficient 
"forming" voltage. I've pulled 63 volt rated caps out of C7s position with
bulged tops due to plonkers (i.e. cowboy technicians) fitting anything they
could find in the way of a 220uF cap when doing the repair.
   

-- 
Security-wise, NT is a server with a "Kick me" sign taped to it.