[vcf-midatlantic] Ti-99/4a Motherboard Troubleshooting

[Bart Hirst]

Hello, do we have any members that can assist with Ti-99/4a motherboard
troubleshooting?  I've already checked most of the "low-hanging fruit"
(voltages, clocks, overheated chips, traces, caps, troubleshooting steps
etc.) and i've been looking at pulseview output of various things with one
of those inexpensive 8-channel FPGA logic analyzers
<https://www.amazon.com/KeeYees-Analyzer-Device-Channel-Arduino/dp/B07K6HXDH1>
you can pick up off amazon for $13.  This unit has the classic "black
screen and tone of death" going on.  So far I haven't been able to find
anything wrong except the 9900 seems to go into a ROM/RAM R/W loop.  Never
makes it to the GROMS.

Bart