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Re: Who can I send my Apple II card to for Repair?
I located another "defect" on the card.
An IC, labeled
74ls14n
Skk8522 AF
Has had a pin removed! (I don't know how the heck it happened. The chip is
soldered directly to the board. Maybe the card was built this way)
Does anyone know what this chip does?
| | | | | | | <----pins got away from the chip
____________ in my ASCII drawing
| |
"dimple ---> } |
in the |___________|
chip | | | | | | |
^
|
this is the BROKEN pin. Pin #2 from the left.
Sandy
TWS wrote:
> (posted and emailed to Rubywand)
>
> Rubywand,
>
> Thank you for the suggestions. I see **NO** toasted components on the board.
>
> PHYSICAL "defects" of the card:
>
> 1) It appears that capacitors got MOVED/ removed. I don't see why this would
> cause a short. 8 Caps on the board are PRESENT, but their connections have
> obviously been soldered on. 8 OTHER caps on the board are NOT present. It is
> obvious that the connections have been soldered on.
>
> 2) There has been a "jumper" wire soldered on to the board (the connections
> look like they were soldered on at the same time the Capacitors were.)
>
> I removed the jumper wire.........NO LUCK. PS buzzzzes.
>
> The GROUND/+5V connectors are at the BACK of the slot connector, correct?
> Those pins are nearest the back of the computer?
>
> IF SO: theres' something _really strange_ about this card. The ground is
> connected to a Capacitor.......the other lead of the Capacitor goes to
> +5V.........?????? DEAD short? That is exactly what is happening (if the
> Ground/+5v pins are located where I think they are) However, I find this hard
> to believe because there have been no modifications to this area of the board.
>
> NOTE: I am guessing that these are capacitors. They are orange Ceramic
> looking blobs. They are labeled on the board as "C-XX" where XX is a number.
>
> 106 +25 K is what the (??capacitors??) are labeled (on the
> component). The K is both UNDERLINED___ and there is also an "overline"
>
> -
> k <---------- kinda like that
> -
>
> Questions::::::::::::::::
>
> Which pins on the board are +5v and Ground? Nearest the BACK or FRONT of the
> computer?
>
> Can someone send me a HIGH resolution, CLOSEUP scan of the COMPONENT side of
> the FRONT (nearest to the keyboard) of the Ohio Kache Systems MultiCache
> board? I think Steven Buggie has one of these cards, could he do it for me?
> There is also one other CSA2 reader that has one of these boards, but I cannot
> remember his name (??John??)
>
> I'd like to check if the board is supposed to have parts C-21==C-24,
> C-17==C-20. Thats what I'd like the scan for. Also, I'd like a scan of the
> BACK (non component side) of the board, near the BACK (nearest to back of
> computer).
>
> This is where the jumper is located, and I am curious if the board is SUPPOSED
> to have this jumper.
>
> Thanks alot,
> Sandy
>
> Rubywand wrote:
>
> > 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