Williams LED issues

Torin

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Donor 2013
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I just got a Joust in really rough condition. My first Williams. I have been working on the boards and when I first got it, all three LED's would light up and the LED on the ROM board would read 1-1-8.

I looked at the CPU board and swapped some RAM chips and now the LED on the rom board isn't lighting up anymore to give errors. It only flashes quickly when I power up. I have checked the ribbon cables and if I wiggle the bigger ribbon cable, it would periodically light up.

Voltages were good on -5 and +12 but low on +5 at the chips before the LED quit on me.

On the PS, there were some really burnt connectors, I replaced the header pins on two of the connections and one of the connectors on the harness. Now, I have LED's 2 and 3 lit up but LED 1 will only light up if I wiggle the large 15 pin connector coming straight from the ISO. I am waiting on a replacement 15 housing for LED 1 from Bob as well as new 4164 chips/adapter.

My questions: Do you think that when I replace the 15 pin housing that is burnt up, that it will light up the LED on the ROM board again? What else is responsible for the ROM LED to not light up? Possibly the ribbon cable?

Just trying to figure out what to troubleshoot before the parts get here.

Thanks for your help.
 
You need to rebuild any headers on the PS board that are corroded or burned.

It sounds like the ROM ribbon cable needs to be recrimped. Here is a link on how to do it in a vise. Just skip over the part about cutting the ribbon cable unless you are going to replace the connector. (link)

ken
 
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