DISK II PROM P5 replacement

3 posts / 0 new
Last post
Offline
Last seen: 2 months 1 week ago
Joined: Sep 3 2005 - 04:23
Posts: 97
DISK II PROM P5 replacement

Hi all,
So I have a spare Disk II card with a missing P5 PROM. I thought I could get a TI 28LA22N PROM and program it with my DATA I/O 29b and the Unipak 2.

First I tried the 3410127A.bin file from here:
http://www.applelogic.org/APPLEASICs.html

But it still didn't work, so I tried the 341-0027.bin file from here:
http://mirrors.apple2.org.za/Apple%20II%20Documentation%20Project/Interface%20Cards/Disk%20Drive%20Controllers/Apple%20Disk%20II%20Interface%20Card/ROM%20Images/

and I ended up with an Illegal bit error when trying to program it. It also didn't work.

Does anyone know what I'm doing wrong?

Thanks

Phil

Offline
Last seen: 4 weeks 1 day ago
Joined: Jun 5 2008 - 07:26
Posts: 451
Re: DISK II PROM P5 replacement

Illegal bit errors indicate that the prom burner has detected a burned fuse that is not supposed to be burned, so you need to try with a different PROM part.

regards,
Mike W.

Offline
Last seen: 2 months 1 week ago
Joined: Sep 3 2005 - 04:23
Posts: 97
Re: DISK II PROM P5 replacement

That's what I thought, so I tried another new PROM and I get the same error.
I have no problem (re)programming either of the PROMs with the first .bin file, only the second one. Strange.

Log in or register to post comments