2600 light sixer keeps reseting after game is over

[machrcode]

not sure if I am posting this in the right spot but this is driving me nuts

tryed pac-man after game is over it resets instantly

tryed asteroids to see if fire button is shorted internally and as soon as game starts it fires automatically and I can not fire it

I have swapped all 3 chips out and does not change tried another switch board that did not work so it is definately something in the logic board

any one know what it could be suspect a bad cap but do not want to guess

any info would be appreciated thanks, Nick

[BigO]

The fire button starts and resets the game on Pac-Man. In Asteroids, you have to release the fire button to fire again.

So, it sure does sound like the fire button is "stuck".

 

The dumb question that I just have to ask: have you tried it without a controller plugged in?

 

Those ports are connected to the 6532 RIOT chip. Seems odd that two chips would have the same failure, but I suppose anything's possible.

 

According to the schematics, there are caps on those 5 input lines that are connected to ground. Activating the fire button or directional controls on the joystick ground the signal. So, the concept of a shorted cap is at least logical.

 

If this thing were on my bench, and I was convinced that the RIOT was good, I'd pull that cap as a troubleshooting step.

 

A logic probe would be useful.

 

 

 

Have you looked in the socket to make sure a pin isn't mangled?

Edited June 16, 2015 by BigO

[zylon]

replace the little soldered buffer chip. this happens all the time 4050BE

Edited June 16, 2015 by zylon

[BigO]

Good to know. That makes a whole lot more sense than any real explanation I could come up with.

Which models have the buffers? They don't show up in the schematics I looked at. They showed the I/O lines directly connected to the RIOT.

[zylon]

Good to know. That makes a whole lot more sense than any real explanation I could come up with.

Which models have the buffers? They don't show up in the schematics I looked at. They showed the I/O lines directly connected to the RIOT.

 

Those buffers usually fail in open or "it fires once and done" or fails to short and will have continuous fire. Combat is great game to try this with.

All 6er models should have them. It is a pain to replace them, but far cheaper than buying new TIA's or RIOT's. The buffer chip actually protects those components and is the first "fail-point" in the system. Here's a good image of one. You can bypass this IC for most failures and then have the same TIA fail rate as a 4sw deck.

I just lean the ceramic cap near it over to the side and use dremel to cut out the IC. Then I remove the pins with soldering iron and clear the holes with a sucker. After clear, I install a DIP 16 socket and new hex buffer. That makes it simple to replace in future.

Is the same method I used on my Sears L6er about 15 years ago and is still working fine.

Edited June 16, 2015 by zylon

[BigO]

Thanks for that info. I haven't run into that failure on one of my own machines...yet. I guess the schematics on here must be for the 4 switch and Junior.

 

I just lean the ceramic cap near it over to the side and use dremel to cut out the IC. Then I remove the pins with soldering iron and clear the holes with a sucker.

It's nothing like ESD safe or temperature controlled, but for the price I don't think you can beat one of these low end de-soldering iron. Way better than those rubber squeeze bulb types. I've never damaged anything with mine. Have successfully desoldered 40 pin DIP's (thought not without some frustration )

 

http://www.amazon.com/Electric-Automatic-Desoldering-Pushbutton-Action/dp/B0002KR9CK/ref=sr_1_10?ie=UTF8&qid=1434484949&sr=8-10&keywords=de-soldering+tool

[machrcode]

is the buffer chip A203 also if this does not work what cap would you guys start with thanks for all of the help, Nick

[zylon]

is the buffer chip A203 also if this does not work what cap would you guys start with thanks for all of the help, Nick

 

Yes. it is the little 16-pin one. just be careful with the traces as the pins come out and you'll be fine.

As for which caps, you would have to follow the trigger lines from port to hex buffer, and then from hex buffer to your main IC's. The hex buffer is known to fail first so it is really the best place to start. Pins 6-7 and 9-10 on the hex buffer are the trigger lines.

[machrcode]

zylon I have to hand it to you that did the trick I got a chip and a socket and put them in and it now fires and does not reset after game is over THANKS!!!!!!!!! glad to see I was not the only one in the world this happened to by the way would that chip going bad cause the light sixer to not work at all??

[zylon]

zylon I have to hand it to you that did the trick I got a chip and a socket and put them in and it now fires and does not reset after game is over THANKS!!!!!!!!! glad to see I was not the only one in the world this happened to by the way would that chip going bad cause the light sixer to not work at all??

 

Glad it was saved instead of tossed. Good job.

yes. If they go bad and short in just the right way inside; all you will get is a black screen if it powers up enough for video. Maybe a humming noise too. it is a "sacrificial part". Might be a good idea to replace the 7805 voltage regulator now as it can be the cause of the problem you just had. I just repaired a board for another member here who had a total failure from the buffer chip. You can check the regulator by playing a long game and leaving system on. use either a volt meter or see if the colors change while playing. 5.2 vdc is the point where damage starts happening. 3rd leg from left when reading the printed numbers.