Stuck output(s) on G80 X/Y Cards / CPU no LED.

I have three sets of Sega G80 X/Y Timing and Control Cards.  All three sets of the ' Timing ' Cards remain stuck a constant voltage  output in the range of 1.50 to 1.66 VDC. Also the ' Control ' Card output  remains at 0.16 to 0.22 VDC on all three ' R G B ' ouputs. I suspect that  this may be the reason that my CPU card will not come up, and the CPU's LED remains off. I have replaced the crystal, on the CPU card, Z80 CPU along with memory (2114) on both the X/Y and CPU Cards. I also replaced the LED, itself. So far I get no output and the CPU seems to be non functional. As a sidenote, I am using an Original Sega G80 power supply / transformer. All voltages(including the Reset power on voltage) measure as ' Good ' . Appreciate any ideas that anyone can offer. Thanks,
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Received on Tue Jan 10 22:59:22 2012