PDA

View Full Version : Repairing an Atari Video Pinball C-380



linuxlove
June 2nd, 2011, 03:33 PM
This was my uncle's system and he let me try and fix it.

Obvious problems:

Buttons need cleaning or are worn out. Large potentiometer may be fully worn out.
Picture is over RF and is pretty hard to see
A wire on the speaker has broken loose


So, where to start?

RetroHacker_
June 2nd, 2011, 05:24 PM
Buttons need cleaning or are worn out. Large potentiometer may be fully worn out.

Usually these kinds of buttons are just dirty - it's not like they got a lot of use. (Except, perhaps, the serve button, and flipper buttons) The pot might be pretty bad though. Isopropyl alcohol is a great cleaner here - use the 91% stuff or better. Drip the alcohol into the switch and try to get as much down inside it as possible - work the switch, pressing it repeatedly, and wiggling it back and forth. Do this a couple times, then allow to dry for a few minutes. Do the same thing for the pot - get as much inside as you can and work it back and forth repeatedly. The alcohol evaporates quickly and doesn't leave residue like some other cleaners do.


Picture is over RF and is pretty hard to see

Check for cold solder joints around the RF modulator, and clean the channel selector switch. Are you using the original RF box, or are you using an adapter? The old TV/Game RF boxes get noisy like this due to dirty contacts in the slide switch. Try another box, clean the switch in the box, or better yet, get one of those RCA to F connector adapters (available at Rat Shack for a few bucks).



A wire on the speaker has broken loose

Resolder broken speaker wire.


So, where to start?
Well, obviously, I'd start by fixing the speaker wire, so you can hear some sound, while you've got the soldering iron plugged in, check for cold solder joints, they're common in this kind of device. You'll probably have to resolder the power connector, those get loose fairly often. Also check for a cold solder joint at the crystal. The crystal is fairly heavy, and a sharp jolt can crack it's solder pads. Won't necessarily cause noise in the picture, but it'll cause it to work intermittently.

-Ian

linuxlove
June 2nd, 2011, 06:18 PM
Usually these kinds of buttons are just dirty - it's not like they got a lot of use. (Except, perhaps, the serve button, and flipper buttons) The pot might be pretty bad though. Isopropyl alcohol is a great cleaner here - use the 91% stuff or better. Drip the alcohol into the switch and try to get as much down inside it as possible - work the switch, pressing it repeatedly, and wiggling it back and forth. Do this a couple times, then allow to dry for a few minutes. Do the same thing for the pot - get as much inside as you can and work it back and forth repeatedly. The alcohol evaporates quickly and doesn't leave residue like some other cleaners do.
I think we've only got 80% Isopropyl alcohol, so I'll be off to look for the 91% stuff next time I'm at a drugstore.


Check for cold solder joints around the RF modulator, and clean the channel selector switch. Are you using the original RF box, or are you using an adapter? The old TV/Game RF boxes get noisy like this due to dirty contacts in the slide switch. Try another box, clean the switch in the box, or better yet, get one of those RCA to F connector adapters (available at Rat Shack for a few bucks).
I've got no idea where the original RF box is so I made a quick little adapter to go from the RCA jack to an RF plug. It might just be the fact that the wires in the adapter are unshielded as the same static problem happens when hooked up to my NES.



Resolder broken speaker wire.
Yeah, I just threw that one in because that's a problem this unit has :P An easy fix.



Well, obviously, I'd start by fixing the speaker wire, so you can hear some sound, while you've got the soldering iron plugged in, check for cold solder joints, they're common in this kind of device. You'll probably have to resolder the power connector, those get loose fairly often. Also check for a cold solder joint at the crystal. The crystal is fairly heavy, and a sharp jolt can crack it's solder pads. Won't necessarily cause noise in the picture, but it'll cause it to work intermittently.
The speaker wire is probably going to be the first thing to fix since it's the easiest to fix.
I'll check the power plug on this but I don't know how often it was used. Myself, I'm using the 6 C-Cells that you can put in here.
Since I built the adapter, I've seen that the unit comes up every time the power button is pressed so I don't think there's too many (if any) bad solder joint issues, but I'll check around and see if any exist.

linuxlove
June 2nd, 2011, 07:11 PM
Alright, did the first couple of repairs tonight.

I took the top off to see how it would be possible to remove the plastic knob from the potentiometer and found out the reason why I couldn't get any input through it - One of the wires had broken loose! As I was inspecting it, the other wire broke loose!
Both wires were soldered back on and the plastic case didn't sustain any melt marks from the iron, which is always nice ;)

The speaker was easy to fix too, just soldered the wire back onto the speaker terminal.

I'm not so sure the potentiometer will need any cleaning since me and my dad played a couple rounds of Breakout and the paddle was quite responsive. The other switches will still need cleaning as they're still dirty and a bit sticky. Those will get cleaned as well as the case. The case is pretty dirty and the label on the top is coming unglued. Does anyone know of a good glue to use for putting labels back into place?

linuxlove
June 7th, 2011, 07:32 AM
Cleaned out the switches with some 91% Isopropyl alcohol and I fear I broke the system. After letting the alcohol evaporate, none of the switches worked, except the power switch. Taking a bit of metal and shorting the switches from the solder side also had no effect.

linuxlove
June 7th, 2011, 01:55 PM
Aha. Fixed the switch problem. During switch cleaning, one of the switches came apart and I had reassembled it wrong. This caused the switch to be stuck in a closed state all the time and was tying up the microcontroller inside. Took it apart again, flipped a metal tab around and hot-glued the switch cover back in place (since the snap tabs had broken) and everything is back to normal.

I also cleaned up the case. There was lots of dirt and grime in those recesses where the speaker is. Cleaned it up with an old toothbrush along with all the removable buttons that attach onto the switch and the whole thing looks a lot better now. I think the case could do with some retr0bright though.

Finally, that potentiometer again... one of the wires had broken loose again. This time, I just soldered a couple new wires from the pot directly to the mainboard. It should stay in place now :/

So, that about wraps up this repair. Everything is working as it should. Thanks RetroHacker_.