14 Aug
1998
14 Aug
'98
2:31 a.m.
On Sat, 8 Aug 1998, Tony Duell wrote:
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.
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.
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 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? 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. 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) 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(a)alcor.concordia.ca
http://alcor.concordia.ca/~ds_spenc/