Which chips are the SRAM? I don't have a hot air station but I guess I could lift them off leg-by-leg like I did with MVS BIOS and solder new ones in if they still are available. I can also trace the other GAL if new SRAM won't fix the issue.
Yes. Though the connection is most likely going to one of the logic chips, instead of the SRAM directly.So I will measure the continuity from u15 socket to those SRAM chips (3x Windbonds), both larger EPROMS and cartridge edge and BIOS?
I will double check those two after work today but I am pretty sure they were connected (unless I mistakenly draw them to wrong places, but I doubt). I can also check if they (U14 pin 8 and pin 10) are connected to some edge or EPROM or BIOS too.Are you sure about the one that goes from U14 Pin 8 to U20 Pin 22? Both should be inputs, so connecting them together doesn't do anything, unless they are connected to another output somewhere.
Also, what about U14 Pin 10 to U15 Pin 8? Both are inputs as well. (Pins 1-11 and 13 of a 22V10 are hardwired as inputs, the rest can be inputs or outputs.)
- U14 Pin goes to U20 Pin 21, not 22! (it is 7th pin from the right, at least I tried to point it in there ).Are you sure about the one that goes from U14 Pin 8 to U20 Pin 22? Both should be inputs, so connecting them together doesn't do anything, unless they are connected to another output somewhere.
Also, what about U14 Pin 10 to U15 Pin 8? Both are inputs as well. (Pins 1-11 and 13 of a 22V10 are hardwired as inputs, the rest can be inputs or outputs.)