Re: Who can I send my Apple II card to for Repair?

[Rubywand <rubywand@swbell.net>]

TWS writes ...

> 
> TWS wrote:
> 
> > I have an OKS MultiCache card that needs some help.
> >
> > When you turn on the computer, the power supply goes
> > "z-z-z-z-z-z-z-z-z-z-z-z-z-zz-z-z-z-z-z-z-z-z"
> >
> > I think the PS is shutting down, because the computer is trying to draw
> > too much power  (which would probably mean a short in the interface
> > card?)
> >
> > I see no fried components.  I do see where some components have been
> > moved or removed.
> >
> > The components are little orange, rectangular blobs o' ceramic looking
> > material with 2 leads coming from them.  I am guessing that these are
> > capacitors  (each is labled C-XX where XX is a number).  I think they
> > have something to do with the RAM on the card, because they are right
> > next to the RAM sockets.
> >
> > Is there anyone who can work on this card?
> 
> By the way,  I got really lucky.  The card did not fry my IIgs.  The IIgs
> will just make buzzing sounds and not boot when the card is installed.
>

     It looks like the board has a nearly dead short. It would need to
suck a lot of juice to shut down the power supply.

     You may be able to repair the board by locating a shorted component
and swapping in a replacement. One way to do this is to connect an Ohm
meter to the +5V and Ground pins of the board-- usually, the + meter
lead goes to the Ground pin and the - or Ground meter lead goes to the
+5V pin on the board and the range is set to Rx10 or Rx100. R should
show as nearly zero Ohms.

     Once you know what the R for the un-fixed board looks like, it's a
good idea to check the board under a lighted magnifier for solder
splashes shorting traces and things like bent IC pins, tiny snips of
wire, burned components, twisted or bent over components, ... which may
be causing shorts.

     If the inspection does not locate the short, then, you can connect
the Ohm meter leads and try pulling components until pulling something
causes R to swing up to some sane value-- something notably different
from zero. Any place where the circuit board seems to have been burned
is a good place to look. Capacitors mounted from +5 to Gnd are also good
suspects.

     If you find a component or components causing the short, replace
it/them and try out the board again.
  


Rubywand