New guy with Defender problem

[jar]

I am new to this site, but find it to be a wealth if information. I am also new to the vintage arcade collecting and electronics in general.

Back in the 90's I worked my way through college working in an arcade. Mostly I swapped out boards when the games were no longer making money.

AT tha time I had a Defender machine at home that also had Robotron boards in it. I built a Robotron control board for the Defender cabinet and was able to switch back and forth in about 5 minutes.

 Long story short, the game died and I moved 800 miles away leaving it in my mom's basement and it was discarded. However, I did strip out all the boards and power supply before it went away.

Fast forward 20 years and I found a non-working Defender on Craig's list for $150. I was told it needed a new RAM board as the ROM board had been replaced so I figured it was an easy fix as I had all the boards.

I swapped out my old boards, nothing. Finally found a bad ROM (#32 on his "brand new" board) and swapped it out. The game fired up and I was able to play it for about 4 hours.

During that time the machine shut down twice, both times indicating a ROM 2 failure. The first time I switched it out and it started right up. About 2 hours later the same thing happened. I didn't change it out as I don't want to burn up any more chips.

 Any ideas on what is causing this? Anyone know where I can find some more chips?

[Kevin Mullins]

#1 thing to do on those is to check the power supply out very closely. (voltages, solder joints, etc) Not only do they develope low voltages, but can also develope HIGH voltages which will cause havic on RAM's and ROM's.

[TheShanMan]

Also check the wiring connectors. Even after I had my boards fully repaired, I was having trouble getting it to boot in my cab. Turned out the connections were sub-par. Jiggling the wiring would make problems appear/disappear.

I would highly recommend buying a repro harness from Dokert on the klov forums. I did, and I couldn't be happier. It's actually better quality than original, and all my problems have disappeared completely. At $65 shipped, it's an absolute steal IMO.

[jar]

How do I find the repro harness?

[SirPeale]

How do I find the repro harness?

I would highly recommend buying a repro harness from Dokert on the klov forums. I did, and I couldn't be happier. It's actually better quality than original, and all my problems have disappeared completely. At $65 shipped, it's an absolute steal IMO.