Desperado:
The GQ-4x is good for manually changing one byte at a time, just by typing over the byte that you see displayed and saving the file. And it can fill blocks.
But I Also I use a Hex Editor program to help.
What I do is read the blank EPROM on the GQ-4x to create a named file of the right length for the particular EPROM all filled with FF's. (you actually get this if you do a read with an empty socket specified for the EPROM type as well as reading a blank EPROM IC) .
Then I open that file in the hex editor, which has the ability to easily fill in any blocks of bytes with any byte you want, or fill the whole file with any byte.
This is the easy way to fill the whole file with byte 00 for example. While you are there, you can manually insert the program bytes , at the correct addresses, from Daver2's program to finish the file & save the file. Then open the file in the GQ-4x and write it into the blank 2532 EPROM IC.
This is the Hex Editor :
So if you can't work it out, using the GQ-4x to fill the file, try the Hex Editor, as it is very intuitive to use.
Make sure to always do a blank check on the EPROM IC before you program it. And, as mentioned before, avoid the 2532A variant of this IC, unless to have an adapter and program it as the 2732A, not 2732.
(It could be worth double checking pin 30 of the CPU as to why there was no signal on that data line when all the other data lines had pulses. I'm suspicious that many of the IC's, which run from the rear 5V regulator, which included the 74154 and the the 74LS00 (A4) have been stressed or damaged by an over voltage event and there could be more damaged IC's in the region of the CPU and the buffers. I'm guessing that probably some conductive material on the bench, while the board was being worked on, transiently shorted the input-output of the 5V regulator that supplies these IC's in the rear board area, or a similar accident. Both the 74154 and A4, must have been working earlier in the repair process. For example, by post #765, the computer had booted normally to BASIC. That could not happen with pins 1 & 2 shorted internally inside the IC A4, so clearly there was a destructive event that damaged IC's after that.)