Just a quick post to document the locations of the ROM's under the PSU.. I find it confusing what ROM goes where, so here's where they all go!
Some older machines have 6 chip TOS installed. Generally I would recommend using one of my TOS adapters and upgrading to TOS104. However on some machines it is not always possible.
As there are 2 basic versions of TOS location , here is a conversion. The left numbers are taken with TOS under the PSU. The last numbers are TOS located on the left of the motherboard. Also see images below.
U4 = HI 0 - U63
U7 = LO 0- U67
U3 = HI 1- U59
U6 = LO 1- U62
U2 = HI 2- U48
U5 = LO 2- U53
STF 6 CHIP ROM LOCATIONS
STF 6 CHIP ROM LOCATIONS
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
Re: STF 6 CHIP ROM LOCATIONS
This is a TOS ROM chip layout for 520ST: