Genesis - Tilt switch closed

[Vengeance]

Having a problem with my Genesis, game was working file, till it decided to stat showing the tilt switch closed message on boot.

I've started going through the ground mods, have done some of them, but not sure that doing all of them is going to fix the issue.

Did a little research and found if you remove the switch connector from the mpu and the issue doesn't go away then the problem is most likely on the board.

When I did remove the connector rather then the tilt switch closed message I got the slam tilt switch is closed message, so I did the mod to permanently defeat the slam tilt switch and after that with the connector removed the tilt switch closed message was on the screen.

Which leaves me to believe that the issue is somewhere on the board. Just not sure where, Clay's guides don't talk to much to how to fix stuck tilt switches or even how to fix stuck switches, or if they are do I'm missing that part of the guides.

So any suggestions would be helpful.

 

[sylvain]

There is a similar issue along with solution posted here:
https://groups.google.com/forum/#!topic ... 9oTyqlB7Rw

Good luck !
- Sylvain.

 

[Vengeance]

Thanks Sylvain, no spare 7400N's sitting around so guess I have to order some

 

[sylvain]

Just a suggestion (I am sure you already know):
If you can, check the inputs and outputs of these TTL chips on the switch matrix (with a logic probe, DMM or scope),
to positively identify the faulty chip before going through the efforts of replacing any.

Cheers,
- Sylvain.

 

[Vengeance]

Just a suggestion (I am sure you already know):
If you can, check the inputs and outputs of these TTL chips on the switch matrix (with a logic probe, DMM or scope),
to positively identify the faulty chip before going through the efforts of replacing any.

Cheers,
- Sylvain.

Yea, I have no idea how to do that

 

[Allan]

Then unless those IC's are in sockets don't replace them you can create more problems than what you started with

 

[Vengeance]

I'm fine with IC chip replacement, I've done that before and socketed chips without issue

It's just the troubleshooting side of things I'm not overly familiar with.

I've gotten by thus far with just taken the word of people smarter then me and doing what other people have already tried in the past