Hi sorry for the late reply, have been away, yes the control screen gets to an initializing stage, there are a series of LED's on whats called the DAMP board and some switches, the LED's are for diagnostics, only one of the memory boards of the six I have in question passes all tests and passes initialization then the machine starts albeit it's another machine of a different configuration, but it still allows me to test all the memory boards I have for faults. One of the switches on the DAMP I believe is the read write switch for backing up and updating the machine, but in the book it doesn't list the ability to back up the SRAM memory, probably so people with many machines had to buy an update card for each machine, but possibly write to backup could be enabled with a hack
I will upload a hi definition image of the board asap.
I think I have identified the correct memory chips in question now the chips are SRAM HM628128LFP-8 there are 9 on the board ... one row of 8 ... and one alone in a separate row ... I think they are two separate purposes.
I assume these are the problem as these chips require a battery.
I did a continuity test to find what pins of the 8 chips are in parallel on the board and only the two pins with the RED ARROWS (NC and CS1) in the attached diagram have no continuity between the 8 memory chips in the 8 array.
There is a 60 pin two rows of 30 header on the board which is used to read/write to the various memory allocations on the board this header is also used for backing up user programs and for memory expansion, I have managed to obtain one of the three different update cards off Ebay the manufacturer would have sent out to the customers to update various things options and base software etc the manual goes into how to flash the memory board with these cards but they are one shot apparently, and no longer supplied as the manufacturer is gone but it may give some clues when it arrives.
There is also an Eprom on the board and I have tried all six of them I have, from non functioning boards in the working board and they all work fine so I am guessing they can be ruled out.
The LED diagnostics indicate the problem is "initialize software" after comparing to the trouble shooting section in the manual ... I think initialize software is something you require a flash card for which I cant get.
Anyway that's just some random observations, the first goal is still to be able to read/write/backup the HM628128LFP-8 SRAM on the memory board and I am guessing the header has the input/output/read/write pins required.
Secondly I would like to build a portable device to send to a person I know with the same machine in the US to read/backup his SRAM and send it back to me and to then write to mine.
When I get the Flash card I bought on eBay I will remove the cover and post a photo.
Thanks to everyone in advance