yah, REXCPM tested clean in the socket, so I should go and look at the code and see if there is some way the socket could be bad and it still tests ok.
On Wed, Oct 21, 2020 at 1:06 PM Brian White <[email protected]> wrote: > 27C256 would be right but you won't be able to use it without a pinout > adapter. Not just the physical carrier to fit the chip in the socket, the > pins are moved around in the M100 socket. > > I would look carefully at the contact between all the pins inside the > socket and the rexcpm board. It's easy for a leg to fail to make contact. > > There isn't really a *cheap* or fast way to make your own option rom. The > pinout adapter and the physical socket connection makes it complicated. > > You could make yourself a http://tandy.wiki/Teeprom. It's easy to do and > all the parts are things you can buy new today, no hunting for old > no-longer-made stuff on ebay. > > But it's kind of silly what that all adds up to, ordering a 3d printed > part, and the eeprom is a ridiculous $9 for a single 32K chip, and you need > to get a soic test clip which is $30 itself let alone a programmer. And > it's not fast waiting for everything to ship. Especially if you don't pay > extra for rush service for the pcb and the carrier. For quick n dirty > testing you could skip the carrier and just glue some cardboard and a > ribbon to the bottom, but you're waiting for everything else anyway. > > I might possibly be able to make an updated version of that which uses a > $1 flash part instead of a real eeprom, and staggered rows of pin holes > instead of a $30 test clip to make a programmer connection, but not today. > > So, asking to borrow one is reasonable. I can lend you something. I'll > email off list. > > Meantime really double check the pin contacts between the rex and the > socket. See if any of the pins in the socket look compressed. > > On Wed, Oct 21, 2020, 11:55 AM Steve Glenner <[email protected]> > wrote: > >> Hello >> >> I’m looking to borrow or buy cheaply any M100 option rom to verify my >> M100 works with option rooms. >> >> I’m trying to get a new REXCPM working on my M100, and running into an >> issue where the software will not run after initializing and loading the >> REXCPM software onto it. >> Basically the initialization program seems to complete without errors, >> initializing the directory and transferring the RXC_11_b39 firmware from a >> disk emulator, but then when I enter “CALL 63012” the M100 sort of hangs >> and various areas of the screen get all black pixels, like the block >> character is sent for a few repeats on random parts of the screen, but it >> never results in a working Rex. Resetting goes back to the basic menu but >> no rexmgr shows up. >> >> I’ve worked with Stephen Adolph a bit on this, he’s sent me a test >> program to test all the memory on the REXCPM which seems to succeed, so I >> next want to verify that the M100 option rom circuitry is working under >> normal conditions. I don’t need any specific rom, and I don’t even need to >> keep it very long if you want it back. >> >> Alternately, I have several microcontrollers and even an old pic-kit >> programmer so maybe I could burn a conventional option rom image to a >> physical EEPROM (I guess a 27C256?) >> >> Thanks, >> Steve >> >>
