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Ballblaɀer

Repairing CX80 fire buttons - help?

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I opened up my CX-80 trak-ball to try to figure out why the fire buttons weren't working, but there was no immediately obvious problem. The contacts all looked fine; I cleaned them anyway. There were no obviously unattached, loose, or frayed wires.

 

Can someone suggest additional ways to troubleshoot? There exists a Field Service Manual for the CX80 (FD100750 REV. 01 February 1984) but I've been unable to track a copy down.

 

The ball itself works well enough and the thing is in pretty nice condition otherwise, so I don't want to give up on it yet.

 

Thanks for any help!

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post-47453-0-49949300-1471140708_thumb.jpg

 

Insert the end of a 3cm steel paperclip into the pin-6 hole of the plug. Check continuity between the paperclip, and the 'BLUE' contact(where the blue wire attaches on the CX-80 pcb.) This is your fire button line.

 

Insert the paperclip into the pin-8 hole of the plug. Check continuity between the paperclip and the 'GRA' contact. This is your ground.

Edited by fluxit

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Thanks. I checked continuity on both lines with a multimeter, and both are okay. I also checked between the button traces/contact areas on the PCB and the wires/pins, and they check out okay as well. So... I'm guessing the buttons just aren't making good enough contact with the traces to complete the circuit?

 

Not sure all my terminology is right here, but I hope I've explained well enough.

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So... I'm guessing the buttons just aren't making good enough contact with the traces to complete the circuit?

Yes, most likely which is much easier to fix than a bad cord. You can peel off the tape holding down the dome and bridge the contact briefly with something conductive and see if you get a button press. If so, you can clean up the area and the dome with rubbing alcohol and once dried use a fresh piece of tape to reapply the dome. If the dome is damaged, like split or crushed than you will need to replace it, you can salvage one from a joystick control if needed.

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Yes, most likely which is much easier to fix than a bad cord. You can peel off the tape holding down the dome and bridge the contact briefly with something conductive and see if you get a button press. If so, you can clean up the area and the dome with rubbing alcohol and once dried use a fresh piece of tape to reapply the dome. If the dome is damaged, like split or crushed than you will need to replace it, you can salvage one from a joystick control if needed.

 

The CX-80 doesn't use dome switches/contacts, or at least none of the ones that I've seen do. It uses small round flat metal contact pads attached to levers that are depressed by each of the trak-ball buttons; they're supposed to make/bridge contact on the PCB when pushed down. This older thread has a photo of the board, but not the levers/pads -- I can post some additional photos later.

 

Edit: This page shows everything.

Edited by Ballblaɀer

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The CX-80 doesn't use dome switches/contacts, or at least none of the ones that I've seen do. It uses small round flat metal contact pads attached to levers that are depressed by each of the trak-ball buttons; they're supposed to make/bridge contact on the PCB when pushed down. This older thread has a photo of the board, but not the levers/pads -- I can post some additional photos later.

 

Edit: This page shows everything.

 

I will pull apart my CX-80 when I get home tonight if I have the time. Best I remember, for the fire buttons it uses two small ancillary boards each with a dome switch very similar to the switches on a CX-40.

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The CX-80 doesn't use dome switches/contacts, or at least none of the ones that I've seen do. It uses small round flat metal contact pads attached to levers that are depressed by each of the trak-ball buttons; they're supposed to make/bridge contact on the PCB when pushed down. This older thread has a photo of the board, but not the levers/pads -- I can post some additional photos later.

 

Edit: This page shows everything.

Ah, I checked and I actually have a CX-22 not a CX-80. Good luck with your issue

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Okay. Obvious questions time.

 

Are you using your CX80 on a 2600? Do regular joysticks work normally on said console(including fire button?)

 

What cart(if any) did you use to determine that the ball works fine, but not the fire buttons?

 

Assuming your CX80 has the mode switch, have you tried both modes(JS/TB) to see if the fire button behavior is the same?

 

Have you tried a non trakball supporting game that can normally be started using the fire button only(reset not required) to see if it can be started using the CX80 in either mode?

 

You should be able to test the 'fingers' of the switch on the board by momentarily bridging the contacts with a small piece of aluminum foil on the end of your finger while a game is running, if you really think that the portion of the switch that is connected to the buttons themselves is really where the problem lies.

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fluxit, thanks for taking the time!

 

Are you using your CX80 on a 2600? Do regular joysticks work normally on said console(including fire button?)

- Yes, and yes. CX22 also works normally.

 

What cart(if any) did you use to determine that the ball works fine, but not the fire buttons?

- Standard copy of Missile Command.

 

Assuming your CX80 has the mode switch, have you tried both modes(JS/TB) to see if the fire button behavior is the same?

- No. I'll give this a go tonight.

 

Have you tried a non trakball supporting game that can normally be started using the fire button only(reset not required) to see if it can be started using the CX80 in either mode?

- Also a no. Another thing to try tonight.

 

You should be able to test the 'fingers' of the switch on the board by momentarily bridging the contacts with a small piece of aluminum foil on the end of your finger while a game is running, if you really think that the portion of the switch that is connected to the buttons themselves is really where the problem lies.

- I'll report back!

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