Amiga A2000 REV 6.2 fixes

“Better video picture”

CPU is in the middle, the two resistor pack have been bent to break them, effectively removing them.

pin 1 network to pin 10 IC pin 1-9 (or 2-9) network at pin 1-9 (or 2-9) IC makes them closer to IC than CPU.

replace (with ?) 1kohm or connect pin 36 of U800 to +5V via 1kohm only needed if the 74ALS245 right next to it is branded from Signetics.

BUT in two board with no Signetics it was in place… and RP903 and 908 were 1kohm.

no idea, not present on my rev 6.2 or another one

“Solves Molly problem”

It connects R215 to +5V_USER instead of EMI200 which goes to +5V.

“Eliminates switching guru”

Tied E from CPU to GND through C and R.

The pin 3 is under the body, on the same level as the others pins of the components on left and right

“Eliminates turbo cards shutdown problem”

Problem solved : unknown

Some informations:!topic/comp.sys.amiga.programmer/jynTJ_Sw7Co

It seems that this .1uF is used to avoid triggering a reset on short pulses (noise…), but some generated by the CPU gets eaten by it. Might be useful to remove if getting issues I guess.

Between U300 and U301, was STILL present on my 6.2 and another one, probably not a fix applied finally.

  • amiga/a2000/rev6.2fixes.txt
  • Last modified: 2019/05/31 21:11
  • by dashie