Could I buy an EPROM from someone? I need a ROM file...

What kind of ROM chip does it use? Is it something that's still available for sale as a blank chip?

If that's a 2732 EPROM, you might be out of luck. I don't think there's any modern EEPROM or Flash that's drop-in compatible. You might be able to find some old 2732 stock, but it's the kind that needs a bright UV light to erase it. Or you could build some kind of adapter board to fit another type of ROM chip.

bigmessowires said:

If that's a 2732 EPROM, you might be out of luck. I don't think there's any modern EEPROM or Flash that's drop-in compatible. You might be able to find some old 2732 stock, but it's the kind that needs a bright UV light to erase it. Or you could build some kind of adapter board to fit another type of ROM chip.

Click to expand...

Jameco appears to 27C32-15's in stock for about $6.

http://www.jameco.com/1/1/3375-27c32-15-eprom-4k-x-8-150ns-5v-dip-24-memory.html

I think you could pretty easily install a 27C64 or 28C64 if you didn't mind running a couple of re-work wires to three of the four pins that will hang over the edges.   And assuming there's room for the 2xc64 to hang out over the end of the socket....

Oh darn it.

I'm pretty sure I have some 2732 EPROMS.  I have a PROM Burner as well -- an old Data IO 29B.

I'd have to figure out how to get the BIN file loaded into it. Let me see what I can do... Gotta get it out of the attic.

It might be easier to just build an adapter, like trag is suggesting. Something like this:



How confident are you that the ROM version upgrade will fix the problem you're seeing?

I have a spare Transwarp 1.4 EPROM handy. Give me an address and I'll pop it in the mail.

bigmessowires said:

It might be easier to just build an adapter, like trag is suggesting. Something like this:

Click to expand...

 Only somewhat simpler, but that's a good image of the concept.

The adapter BMOW showed looks like one designed to adapt 1 Mbit and larger EPROM (and EEPROM and Flash) to 512Kbit and smaller EPROM-using devices. There are considerable differences in the pinout between the 512Kbit and the 1Mbit chips.

However, the 32Kbit and 64Kbit have identical pinouts except for the last four pins at the end of the chip, pins 1, 2, 27 and 28. Technically, 26 is different as well, but it's NC on the 64K and Vcc on the 32K, so there shouldn't be any problems there. However, pins 2, 27, and 28 are A12 and WE_ and Vcc respectively. WE_ should be tied high, and A12 should be tied either high or low. It doesn't really matter as long as you're consistent about it and remember to program the corresponding half of the chip. Pin 28 needs to be connected to power, so high again. Pin 1 is a NC.

In theory you wouldn't even need a socket. Just wire up the three pins on the end of the 64K chip and connect the wire to pin 26 and plug the other 24 pins (including 26) into the host socket.

rickrob said:

I'm pretty sure I have some 2732 EPROMS.  I have a PROM Burner as well -- an old Data IO 29B.

I'd have to figure out how to get the BIN file loaded into it. Let me see what I can do... Gotta get it out of the attic.

Click to expand...

Wow, thanks!

Mailed it yesterday morning

OK , I'll put the PROM Burner back in the attic. 

I would be able to help with burning an eprom also. Since there is one on the way keep this info for future problems.

I got the ROM, thanks for all the offers.

Did it work? 

I popped it in over break.  As suspected by others, it didn't make any difference when using the original CPU.  However, when I replace the CPU with my IIgs' CPU, it seems to fix it.  It does still have some floppy quirks, but I was able to use it for a good 45 minutes without it crashing or rebooting.