Re: Fixing Apple II Mouse Card

[tomk@pro-nsdapple.cts.com (Tom Kelly)]

Unknown User writes:

>a.gov!tesuque!lynx.unm.edu!musca.unm.edu!buggie
>From: buggie@musca.unm.edu (stephen e buggie)
>Newsgroups: comp.sys.apple2
>Subject: FAILED IIE MOUSE CARD ---- WHICH CHIPS IS LIKELY BAD?
>Date: 10 Feb 1997 17:29:44 GMT
>Organization: University of New Mexico, Albuquerque
>Lines: 15
>Message-ID: <5dnlu8$egd@lynx.unm.edu>
>NNTP-Posting-Host: musca.unm.edu
>X-Newsreader: TIN [version 1.2 PL2]
>
>
>I zapped my IIe mousecard in my stealth-IIgs.  Doesnt work at all.   In 
>fact, with mouse connected to the card, the IIgs self-test will not start!
>
>Which IC in this card has likely failed?
>
>If anyone has a non-working IIe mousecard, I'd offer $3 plus $2 shipping 
>to get it to see whether, but chip desoldering and swapping, I could get 
>it to live again!
>
>
>Please reply by e-mail with a copy to the net.
>
>Steve Buggie	buggie@unm.edu
> 


Why do you have a mouse card in a IIgs?
 
If you have another good card swap socketed parts.
 
1) The one mouse card that I fixed had a bad 74C245 (B3).
That chip connects directly to the buss so that would cause the conputer to
lock up.  Just cut the pins to the chip and de-solder the pins one at a
time.
Replace the chip with a IC socket and plug new chip in socket.
If you can replace with correct part.
I did not have a 74C245 so I used a 74LS245.  It worked just fine.
You can experiment, but I would avoid 74245 and 74H245.
The 74F245, 74L245,74S245,74HC245 might also work.
 
2) Next replace 74LS74 (B1)
 
3) B2 and B4 are ROM/EPROMs.
 
I can provide all parts except (A3)
 
I'll sell good card for $20.00 and your bad card in exchange.
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