Ron,
Well I have used my GQ4x4 for many years and it works fine for me. But you shouldn't have to keep heating your solder joints if you had quick solder flow on each pin. Seems strange that the original NVRAM that was ok when you unsoldered doesn't work but It could have gotten messed up in the process. Can you just go beyond the error and get a normal display? Review the resistor ladder circuits with your ohm meter ahead of the DAC chip.
I know this may not be helpful, in years past I used to send all my A5’s to QService for repair and probably over 50% of the NVRAM chips he tried to copy he couldn't get data saved, he is very qualified in repair of these modules. But now I do the work myself and I haven't had an issue saving and reprogramming data. But I also replace caps and any other resistors needed to correct ladder circuit. So it’s probably not your programmer.
Craig Cramb