On Sat, 8 Aug 1998, Tony Duell wrote:
> > I cleaned out the mouse, but I haven't done anything else yet. Tony gave
>
> Did you just remove the ball and clean the rollers, or did you take off
> the cover and blow the dirt out of the optoswitches?
Blew the dirt out of the optoswitches, as well as I could. I didn't feel
like braking the little wheels while trying to remove them, so I didn't.
> > me some info on how the critters work, but I haven't had time to look into
> > it yet. I still don't know if it's the mouse or the Mac with the fault.
>
> One good thing - if it is the mac, then it's one of 2 standard chips -
> the 8530 SCC or the 6522 VIA. Neither are hard to obtain.
Great! I dread opening up the Mac, though, so I hope it's the mouse.
Only the ROMs are socketed, and there's that nasty CRT and power supply
just waiting to kill me.
> > One useful thing would be the Mac's mouse port pinout, though, so that I
> > at least know what pins to look at. And the Apple //c's, too.
>
> OK, here's the Mac (128/512/Plus) pinout
>
> 1 Ground
> 2 +5V
> 3 Ground
> 4 X2 (VIA PB4)
> 5 X1 (SCC DCDA)
> 6 N/C
> 7 Switch (VIA PB3)
> 8 Y2 (VIA PB5)
> 9 Y1 (SCC DCDB)
Excellent! Thanks. Maybe I'll wire up a spare Amiga mouse first to see
what happens. :)
According to the "Introduction to Amiga" book I got with my A1000, the
mouse pinouts on the Amiga are as follows:
1 Mouse Vertical
2 Mouse Horizontal
3 Vertical Quadrature
4 Horizontal Quadrature
5 Mouse Button 2
6 Mouse Button 1
7 +5V (125 mA)
8 GND
9 Mouse Button 3
So I guess Mouse Vertical on the Amiga mouse would go to Y1 on the Mac,
Vertical Quadrature to Y2, etc?
> I'd start by looking at the appropriate pins on the mouse connector with
> a logic probe.
THAT's the item I forgot to shop for today (logic probe). I finally got
the replacement NiCd battery for my Amiga 3000, and a fresh roll of rosin
core solder, but I felt like I should be looking for something else while
I was spooking around electronics shops. Of course, I have no idea what a
logic probe costs... but I found instructions on how to build a simple one
in an old Sinclair book I was looking at last night.
> If one of the 'Y' signals is not changing state, then look
> in the mouse. If they both are, then trace the signals through the RFI
> filters (the yellow DIP packages near the back of the logic board) to the
> pins on the chips. If they don't get that far, time to replace the RFI
> filter. If they do, then check/replace the VIA or SCC chips.
Makes sense, and doesn't sound too hairy. Once I get a logic probe.
> As I don't have a real Apple mouse, I can't be more specific, alas.
It seems a lot of people have dead or missing Apple mouses.
> -tony
Doug Spence
ds_spenc_at_alcor.concordia.ca
http://alcor.concordia.ca/~ds_spenc/
Received on Fri Aug 14 1998 - 02:31:07 BST