LC 475 after PRAM battery change: mouse only moves up/down. Keyboard, only shutdown button

[Saldali]

My LC has been powered off for 1 or 2 years and had a dead PRAM battery (not leaky). That prevented it from booting.

I changed the battery. The computer now boots alright, but has these strange issues:
- The mouse cursor only moves up and down but not sideways; it seems to want to move a pixel left or right, but always comes back to the same horizontal position near the left edge of the screen.
- The keyboard worked jerkily at first; then, not all. Now, only the shutdown key works.

During boot, the keyboard leds blink once and that's all. Caps, insert end scroll leds won't turn on.

The computer has only one ADB port, so the keyboard plugs to it, then the mouse plugs to the keyboard.

Tried plugging the mouse directly without the keyboard. Same thing, only vertical movement.
Tried reflowing the adb port welds. That had no effect.

I only have this mouse and keyboard, don't know anyone who could lend me a keyboard and mouse.

I have no idea if this one problem with the adb port, or two different faults - both the keyboard and the mouse.

Can any help to sort this out?

BR
A.Salvador

 

[robin-fo]

Remove the mouse and remove any dirt which might have accumulated. Also check the Mac logicboard for any leaking capacitors.

 

[joshc]

Can we see some pictures of the logicboard please

 

[cheesestraws]

Have you tested the keyboard on its own? Does that also fail?

 

[bibilit]

I agree with robin-fo, probably dirt.

Remove the ball and try spinning both axis directly through the opening.
A small rubber tube is directly driven by the ball…if the tube is covered in dirt, the ball is unable to spin it.

 

[Saldali]

Have you tested the keyboard on its own? Does that also fail?

Yes, the keyboard on its own makes no difference.

First time I booted after the battery change, the cursor keys and the tab key were sort of working. I was able to cycle the icons on the screen using those keys; but if I pressed them too quickly, the highlighted icon would sometimes jump two at a time or not jump at all. After having unplugged the keyboard to push it in more firmly into the adb socket and gently bumping the keyboard a little bit on the table, then even those keys stopped working. Now, only the shutdown key works, but I'm not able to confirm the shutdown because ENTER doesn't work.

 

[Saldali]

Can we see some pictures of the logicboard please

Sure, joshc.
Hope you can spot something.

 

[Saldali]

Remove the mouse and remove any dirt which might have accumulated. Also check the Mac logicboard for any leaking capacitors.

robin-fo, I opened up the mouse. Sure enough, I was surprised by the amount of gunk inside it.
I used my lungs to blow the dirt out from inside the mouse. I blew a lot toward the encoders and the photocells, should there be any debris stuck in between. I'm glad I did that. However it made no difference in regards to my problem. Only the vertical direction roller is making the cursor move, as I turn it with my finger.

As for the capacitors, there's no more electrolytics in the board, as I've replaced them all with ceramic ones long ago. Although there could be some previous damage from the old capacitors, I can´t see any sign of it - and the machine has been working for a long time after the recap.

 

[imactheknife]

robin-fo, I opened up the mouse. Sure enough, I was surprised by the amount of gunk inside it.
I used my lungs to blow the dirt out from inside the mouse. I blew a lot toward the encoders and the photocells, should there be any debris stuck in between. I'm glad I did that. However it made no difference in regards to my problem. Only the vertical direction roller is making the cursor move, as I turn it with my finger.

As for the capacitors, there's no more electrolytics in the board, as I've replaced them all with ceramic ones long ago. Although there could be some previous damage from the old capacitors, I can´t see any sign of it - and the machine has been working for a long time after the recap.

No bent pins on thr mouse or keyboard?

 

[Saldali]

Ok, so I finally got a "new" mouse from ebay and that one works fine! It's a big sigh of relief for me, because the logic board seems to be ok after all.

Now, to try and figure out how a mouse and keyboard both went dead at the same time. What could have gone so wrong?...

 

[luRaichu]

Now, to try and figure out how a mouse and keyboard both went dead at the same time. What could have gone so wrong?...

Maybe the logic board killed them

 

[Saldali]

So, to put an end to this mystery:

I was able to fix the original mouse...
I switched over the IR leds and photo-transistors, of the horizontal and vertical encoders. Then, both directions started to work fine. Maybe the horizontal encoder led or photo-transistor had a bad solder joint?

I was able to fix the keyboard...
The ribbon coming from the membrane is held by simple touch contact against the keyboard's PCB - not even a socket is used.
I cleaned the membrane contacts with a q-tip and contact cleaner. After that, it was working again. Maybe it fell victim to a moisture strike?

The logic board was alright all along - so I hope.
I was having nightmares about trying to source some exotic custom "Cuda" IC.

I thank the Board for all the input given.

BR
A.Salvador

 

[cheesestraws]

Glad to hear it! Yes, that's a relief. Sometimes multiple things do happen at once.

Glad it's fixed.