HELP! Trying to do Rom swap on Mega ST. Not working!

[mons2b]

After some advice I have tried to swap some roms from a 520 STE into a German Mega 2 to get an English desktop. But I just get a white screen with yellowish border. Have I fried the computer or the Roms? I am now going to try to put the German Roms back in...

I have found some reference to "Upgrading TOS from a 2 chip version to a newer 2 chip one is quite simple, provided you change two jumpers on the motherboard (W102 and W104). The instructions on how to do this can be found here :

http://bales.free.fr/atari/files/text/tos_ste.txt"

But that link is dead! Is the reason for my white screen of nothing because I havent changed some jumpers? Its 2 chip to newer 2 chip. What jumpers? How?

 

JW

Edited January 9, 2007 by mons2b

[mons2b]

Ok I managed to get back to the German desktop! Thank god! Thought I had blown the Mega.

[+Guitarman]

I had posted this in another thread but may apply here. I think if you are going from 2 chip to 2 chip, you shouldn't have to change anything. The TOS roms should be the same through the 16bit models. I think you only need to change the jumpers when switching between 2 and 6 chip TOS versions. If I'm wrong, please correct me. Here is what I found when upgrading my MegaST

 

There is a mod to the MegaST board if switching between 2 & 6 chip roms. For those who are thinking about changing TOS versions, this may come in handy.

 

For 1M x 6 Roms you have to remove U12 (74LS11) and set jumpers W2 to 2-3, W3 to 2-3 and install jumper W4.

For 256k Roms remove U12 and set jumpers W2 to 1-2, W3 1-2 and install W4.

For 1M x 2 Roms, set W2 to 2-3, W3 to 2-3, remove W4 and install U12.

 

All listed mods are at the lower left corner of the main board, near the rom sockets.

[tjlazer]

So you are trying to use TOS 1.6 on a MegaST? Might not work. If you need TOS 1.4 pmail me.

Edited January 9, 2007 by tjlazer

[jens]

An STe version will not work.

The STe TOS version only work with STe's.

 

So no 1.06 or 1.62.

TOS 2.06 will work however as the latest TOS for plain 68000 Ataris.

[mons2b]

An STe version will not work.

The STe TOS version only work with STe's.

 

So no 1.06 or 1.62.

TOS 2.06 will work however as the latest TOS for plain 68000 Ataris.

 

Ok. I found the STE didnt work either when I put its Tos chips back in. I assume this is because when I removed the two Tos chips from the 520 STE a couple of sets of pins were bent out so they wouldnt contact the socket. Thinking these might be needing to be correct for the Mega I bent them straight. Since I put them back the STE its doing the white screen thing the Mega did.

To cut a long story short can someone tell me which pins to bend out so that they will work in the STE again?

 

JW