Power Supply / timer question...

[zim64half]

Howdy all.

This is my first post here - so please be gentle!

This is a very specific question, but I was hoping that maybe someone has run into it before.

I have a cocktail (table top) version of Taito's Space Invaders II. It does not work now, though I have played it myself at the previous owner's home.

I have it now because the PO did not want to bother to have it fixed.

I pulled the 3 CPU boards out of it, and brought them to a local guru who is currently repairing them.

This guy mentioned that all 3 had problems, which led me to look into the power supply.

It is fried too. It is probably the cause of the dead cpu boards too.

This power supply is a TDK 2EF5765 (aka Taito AAM60009)

I do not want to repair this power supply, as it was basically crummy to begin with (IMHO) - and I dont really want to pay this guy to fix that too... I would like to use a modern power ATX power supply, but I noticed one problem:

I can get all of the voltages I need (+12, +5, -5) but there is one wire going from the original power supply to the CPU harness that is not for power.

It is basically connected to the output of a NE555N timer chip.

Can anyone explain to me why a power supply would be sending this signal to the CPU boards? Is it really needed? Is there an easy way around it if it is needed?

Thanks in advance!

-Zim

[itobandito]

I think it would be easier to get a switching power supply for around 50 bones or so. Most arcade repair shops online sell them. Just my opinion. I have heard of using a PC one though.

[FABombjoy]

It's probably part of the "power on reset" circuit. You can either tie it to ground, or build a simple replacement. It'll work either way, but grounding it will cause the game to take a little longer to boot, and may be accompanied by extraneous sound effects.

FWIW, if you decide to give up on those boards, I'll buy them from you.