I have removed and reseated both the EPROM and RAM chips. I read out the contents of the EPROM and they match the 1.0 firmware binary in the Files section. Two different 9V adapters have been tried with the same results. I replaced the regulator, it gave 5.11V before the change and now gives 4.95V. The battery only gives 2V or so but the anomalous behavior happens independently of whether the battery is installed (it's currently in place but desoldered, so I can raise one tab off the PCB to disconnect it). I have ordered new tabbed and tabless batteries and battery holders and will install one when they arrive although I doubt the problem is related to battery voltage once the unit is on and an attempt to reset the RAM has been made with the Enter key. I also ordered a 256K RAM chip for extended storage and will install it when it comes in. All buttons were tested and they conduct properly when pressed. I also checked all electrolytic capacitors and although old, their values are within reason.
Has anyone encountered this behavior with this or any other Perf/X board? Any recommendations as to where to look next? Thanks for any assistance.
Best regards,
Tony