exxos's Atari, Amiga & retro forum

16MHZ OPTIONAL FIX

I noticed the MMU 16MHz line isn't actually buffered via the 74F04.. Which was actually part of its intention.. :roll: I am classing this as a optional fix as it should not affect anything much..

The fix is simple, lift the yellow end leg of R910 , connect a small wire from the now lifted side, and connect the other end of the wire to pin 10 of the 74F04 (IC900) as circled in red.

I know there are several fixes documented here, but for a 1 man job, you have done great!

I can imagine engineers at Atari Corp going through all this revision testing lol. Here you are doing it all with just a few brave volunteers.

Great props to you and all the testers. :cheers:

GLUE DATALINE FIX

A "good" mistake here.. While GLUE states D0 & D1 on the GLUE itself, the actual data lines are D8 & D9! So nothing will be setup right internally on the GLUE and pretty much everything it controls will be "wrong" because it will be getting bad data. The fixes are thankfully not too bad...


STEP 1

Cut D0 & D1 tracks on the bottom of the PCB as highlighted with the redline.


STEP 2

Cut the track on the top of the PCB as highlighted with the red line.


STEP 3

Connect a bodge wire from the glue to the resistor pack as highlighted the redline.


STEP 4

Connect a bodge wire from the CPU to the resistor pack as highlighted the redline.


STEP 5

Connect a bodge wire from the glue to the resistor pack as highlighted the redline.


Done :)

What we basically have done is rewired the GLUE's D0 to D8, and D1 to D9.

Hopefully this will solve a great number of issues :)

Thanks for playing Atari :) :lol:

MFP FIX

Fixes missing pull up resistor on MFP pin 32 (IRQ).


Solder a 1K resistor on the bottom of the PCB connected between the highlighted yellow circles.

GLUE DATALINE FIX - Patch in place on board. Also shows the pull up fix as well.

exxos wrote: 24 Sep 2018 13:22 MFP FIX

Fixes missing pull up resistor on MFP pin 32 (IRQ).


Solder a 1K resistor on the bottom of the PCB connected between the highlighted yellow circles.

mpfpu.JPG

Patch in place:

RAM RW FIX

Fixes wrong RW line connected to RAM.

STEP 1

Cut track on top of PCB as shown below.

STEP 2

Bodge wire connected as shown below in red.

STEP 3

Pray to whichever god you believe in, or do a ritual chicken sacrifice and voodoo dance.. or do both to be sure... (uploading such events to youtube is also recommended).

LMAO at chicken sacrifice. I take it with the MMU ram board I won't need to do this? probably still do it anyway?

Forgottenmyname wrote: 25 Sep 2018 17:49 LMAO at chicken sacrifice. I take it with the MMU ram board I won't need to do this? probably still do it anyway?

That's a point, it shouldn't affect a plug in MMU RAM board...

But I am getting corruption that I didn't have when I just had the E7 error repeating.

I'll do the patch anyway, for continuity but I think we might need to look somewhere else too.