[comp.sys.atari.st] Mega ST 2 with old roms

holzer@ztivax.UUCP (Walter Holzer) (04/03/89)

Hello,
I wanna to make some changes to my rom's, eg. FVERIFY, CH_HZ, new character sets and so on. Because the price of the 128k-eproms in Mega ST are unable to pay, I wanna install the 32k-eproms...

If you're looking to the schematic diagrams of an Atari Mega ST2, you'll see, that Mega ST 2 can run with old roms. To get this, you have to do the following things:
- Plug out chip U12 (or disable pin 12)
- Jumper W2 from 2-3 to 1-2
- Jumper W3 from 2-3 to 1-2
- Jumper W4 close.

I've done this but nothing works. I've tested with some rom's but they will only run in old Ataris.
Any solutions are welcome, especially pratical solutions and not only theorie.
Any idea, if I need the UDS and LDS signals to get the work?
Thanks in advance
Matthias
-- 
Walter Holzer & Matthias Dominick    Internet: holzer@ztivax.siemens.com
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