Robotron Interface Board or something else?

morphis72

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I have a Robotron that I started working on recently. I replaced both the ribbon cables and did the usual cleaning and reseating of chips and got it to boot. The game seems to play normal except my guy is always running to the left. I can stop him by pushing the joystick to the right but he will not move right. up/down works as well as up-left and down-left.

I cleaned the connetctor pins, reflowed the headers, and checked continuity through the ribbon cable. Everything seems fine.

I haven't changed the two connectors out that are on the orange wires but I tested with JROKs multi board and all controls work completely normally.

switch back to the original hardware and my guy runs left again but this time some the firing directions don't work. Mess with it some more and I get all the directions for firing working again but I am not sure if it was poking and prodding or just the reboots that did it.

In test mode I do see all directions register on the screen but 'move left' never stops.

I checked all the diodes and resistors on the board but didn't take them out of circuit. I got the same reading on all of them so I 'think' they are okay.

Any ideas on this? is one of the chips on my interface board bad or do I need to look elsewhere?

I have a Defender interface board but I am about 90% sure you can't use a Defender board in robotron but you can go the other direction with it.
 
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If you disconnect the control panel wiring, does it still go left? If it does, that rules out the controls and associated wiring.

If you have a spare widget, then that is a quick test. Also, does your widget have the two large chips socketed? If so, reseat them if it goes left with the wiring disconnected.

The Defender widget will not work with your Robotron.

Scott C.
 
If you disconnect the control panel wiring, does it still go left? If it does, that rules out the controls and associated wiring.

If you have a spare widget, then that is a quick test. Also, does your widget have the two large chips socketed? If so, reseat them if it goes left with the wiring disconnected.

The Defender widget will not work with your Robotron.

Scott C.

I unhooked the control panel and the issue stopped. Hooked it back up and started poking the widget end of the new ribbon cable and got changes in behavior. Starting to think the new cable is an issue.
 
Just in case anyone was wondering - I removed the new ribbon cable for the interface card and put the old one back on. Now the game is working perfectly.
 
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