Help needed: which parts for my Mega ST upgrade to 2.06

[Emwee]

Hi!

I am new to the Atari (Mega) ST world and in the beginning of upgrading my Mega ST - right now I want to get (if possible) a switchable upgrade to TOS 2.06, currently installed is 1.4.

The inside of my Mega ST 4 is like this:

Atari_MegaST4_04.jpg (793.27 KiB) Viewed 6119 times

Are this parts from the store the correct ones for the upgrade?
16MHz BOOSTER & TOS206 DECODER

NEW MC68000 DIP CPU (If I want to use the booster function)

MEGA ST DUALTOS PCB + the mentioned needed parts

and

ATARI STE 1.62 / 2.06 TOS ROM
...the ROM is where I am absolutely unsure, can this one be used?

Or should I choose a different way for the upgrade?

[exxos]

This is the ROM you need.
https://www.exxosforum.co.uk/atari/store2/#0050

TOS 206 decoder
https://www.exxosforum.co.uk/atari/store2/#0212

[Emwee]

Many thanks for your help, I've ordered the mentioned parts

[robbo007]

Hi,
I'm wanting to do the same for my Mega 4 ST. Do you have to do any hacks the the motherboard to use this? Or is it just plug in and thats it?

Is the dedicated ROM decoder like a switching device so you can switch between different TOS versions? Does it plug into the port on the side of the Mega?

These are the parts that are needed are right?
[0248]
[0050]
[0008]
Thanks,

[exxos]

Unfortunately the decoder 0248 was found not to fit the mega ST.

So there is only the CPU type which you can really do.

https://www.exxosforum.co.uk/atari/store2/#0212

[robbo007]

So I would have to de-solder the current CPU and stick the decoder 0212 under it and use [0050] and [0008] parts also?

My main goal is to change the Germany TOS 1.04 to English TOS 1.04. Not sure if its more hassle using the dual TOS solution or going the 6 ROM TOS 1.04 version? Do I have to hack the mainboard for the 6 ROM 1.04 TOS solution? Apart from soldering on the ROM holders to the main board.

[exxos]

So I would have to de-solder the current CPU and stick the decoder 0212 under it and use [0050] and [0008] parts also?

Yes.

My main goal is to change the Germany TOS 1.04 to English TOS 1.04. Not sure if its more hassle using the dual TOS solution or going the 6 ROM TOS 1.04 version? Do I have to hack the mainboard for the 6 ROM 1.04 TOS solution? Apart from soldering on the ROM holders to the main board.

Sounds like you have 2 chip tos now then ?

6 chip will need the sockets soldering in for TOS104. It may need some jumpers altering but I'm not that familiar with the mega.

As to what is easier.. that's up to you. If your not very good at soldering and removing the CPU then I'd suggest not going down the 206 route as you could damage the motherboard removing it.