#NO MOUSE MOVEMENT !
28 messages in this thread
In times like these when Amiga future looks somewhat uncertain… I've been
thinking I'd like to revive my 1000 [D
It works fine except the mouse will not move the pointer at all. I
have no idea why this is and could use some input from some one. I am
capable of unsoldering and replacing chips if I knew which one. Can
someone help???
Sounds like one or both of your 8520's blew up. They're socketed on the 2000
(I've had to replace mine), but I'm not sure about the 1000.
I was told that. The CIA chips right? I bought some chips and couldn"t find
any of that number in the 1000 machine. I've had to replace those on a 500 I
had. I don't know if the 1000 has a different CIA # or what.
I don't know what they'd be on the 1000. Sorry. 🙁
Dan
there are some fuses going to the mouse ports which blow from time to time.
thanks for the reply! Any idea what these fuses look like and where they may be
on the 1000 machine??
Dan,
My prints for the 1000 don't show any fuses. I believe they were added
to the rev 6 2000's. The schematic does show a two transistor circuit
– current limiter maybe – driving the 5v out the mouse port. The
easiest place to check is between the middle two pins on the bottom
row of the mouse port. There should be 5v there.
Jim
I found out about the fuses when one blew on my 2500. They look like little
caps or coils. The other place to look is the user 5v line.
-ash
Kyfho
Yes, I've replaced a lot of fuses on rev 6 2000's. But I've never
seen fuses in the earlier 2000s, the 500 or the 1000. Usually the
traces act as fuses. 🙂 (I used to be a service tech..)
MOS via Autopilot & Amiga
Thanks jim! I'll check that and get back to you. If the voltage is missing what
does that tell us? Problem in that circut? I'll check the voltage THEN ask you
where the transistors are …
If the 5v is missing, it could be that circuit. Or it could be a burned
trace on the board.
MOS via Autopilot & Amiga
OK heres what I have… I do have 5v on the middle bottom pins of each
connector. The joystick works in post #2 when I boot a game. the fire button
works in post #2 and the mouse button works in #1. The mouse still WILL NOT
move the pointer. The pointer will move by using the Amiga, alt, & pointer keys
together. It's almost like the mouse is the problem but its the same one I use
in my 2000. Here's a silly question… Was there a 1000 specific mouse ????
There was a unique mouse that came with the 1000, but it was just a
connector difference.. It had a "sideways" plug to allow for any expansion
devices that might be plugged into the bus slot. Any Amiga mouse will work
ok on the 1000.
Since you have the 5v, and the stick works in port 2, it sounds like a
logic failure. I don't think it's the CIA chips, so I wouldn't bother
looking for them. The Fire & buttons go through the CIAs, but the
directional signals go through a multiplexor and into Denise. The mpx
switches between the two ports & routes one at a time to Denise. So…
that chip could be bad, I've seen this sort of failure before. Or the
clock line that does the switching could be missing. (I'd tend to blame
the chip myself… ) It's a 74LS157 at U1M on the motherboard. It's
underneath the floppy disk, and isn't socketed…..
-Jim
MOS via Autopilot & Amiga
Dan
If you plug the joystick into the mouse port and move the joystisk around, does
anything happen to the pointer?
-ash
Kyfho
no… the joystick does not work as a mouse. I cant think of any games that
require a stick in port one so I havn"t tested it that way but i guess i should
investigate…
Dan
A digital joystick will move the cursor.
Left Joystick = up cursor and back Right jorstick = down cursor and back
clockwise rotation = up & left cursor movement Counter clockwise rotation =
down & right movement
This will give an idea of how much of the port has gone away.
-ash
Kyfho
Jim, does your print show any 8520 CIA chips ???
Yes, there are 2 of them, just like the other Amigas. They're behind the
floppy drive, next to the CPU.
MOS via Autopilot & Amiga
Ok… I have it apart. This 1000 has the insider 1 meg ram board installed. If
the cia chips are on the main circut board I can't see or get to them without
removing the ram. Any one ever had to do this? doesn't look easy… Thanks Jim.
If I recall, an insider board would cover the CIA chips. But as I said in
the other message, I don't think those are your problem. At this point,
you need a 'scope, or the nerve to "shotgun" it & replace that 74ls157..
or visit your friendly Amiga service shop… 🙂
Good luck… -Jim
MOS via Autopilot & Amiga
Well Jim thanks for all your good help. I failed to mention that I've already
replaced that Very chip. It was the only thing I could think to do and it was
the only chip I could see that was in a direct line only with that port. I dont
know how well I actually did with the repair. As I remember it it wasn't an
easy chip to replace. I do have a scope here but am not real sure how to use
it. Is there a way to check this chip in place rather than R & Ring it again ?
Thanks in advance… -Dan
Dan, it looks like I misunderstood that chip's function. It doesn't
exactly switch the denise between the two ports. It actually alternately
looks at the directional signals and the quadrature signals (those are
used on mice & trackballs only to give direction). So… I'd suggest
powering up with the mouse installed. Look at pin 3 on the '157 while you
roll the mouse forward or backward. Do the same on pin 2. You should see
pulses. Then move to pin 4 and move the mouse forward again. That's the
output. You should see pulses there. If not, look at pin 1. That's the
clock line doing the switching of the '157. If that's missing, go back to
a 74F74 at U8I and look at pin 9. That clock does stuff all over the
system, so it's probably there. You could also try swapping out the denise
chip, before getting too heavy with the scopin'.
-Jim
MOS via Autopilot & Amiga
ok jim I'll try some of that tonight. If I were to just replace the Denise I'd
have to buy one because No way will I tear my 2000 apart to swap chips. I'm not
that lucky. Is there any difference in those chips? an upgrade maybe? also…
as i may have said I've got this Scope here but never used it. Any suggestion
where to set its values to read the pulses you suggested looking for?? Thanks!
-Dan
The fuses should be near the mouse ports, between the ports and a dip
(74LS157). On the 2000 the mouse ports are connected to Paula, power and the
dip. I see no connection to the CIAs.
-ash
Kyfho
Dan,
The 8520's in the A1000 are the same as in the newer machines. My
memory is they're towards the back of the machine.
Don