STF 6 CHIP ROM LOCATIONS

[exxos]

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

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[tzok]

This is a TOS ROM chip layout for 520ST:

520ST ROM layout

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