Recent content by Bruce72

squeezing every mb/s out of the standard A3k SCSI with the "WD33C93 Turbo Interposer" (https://github.com/reinauer/wd33c93). SCSI Bus now clocked at 20MHz For me, it was only a slight speed increase, but only from about 3.7MB/s to 4.4MB/s. But it's why we do these things. ;)

I would go over with extra fine detail U452, U453, U478, U479, all of the RP4xx's in the local area. Then also confirming that your tick jumper (J350) is set to VSYNC, and that your VSYNC is measuring correct on an oscilloscope.

I can't speak to -15's, but certainly had no end of trouble with the -5's and moving to -10's fixed all my issues that I had. I would go over that whole section of the board with a microscope checking for bridged/missed solder points especially on the resistor and capacitor networks as well as...

Can you try booting with the flicker fixer enabled (switch down) and then once booted disable it and advise? Also, what speed gal's did you use for U460 & U461?

I am, and was just looking through my notes on previous builds, but the issue I had was that the system wouldn't boot with the flicker fixer ENABLED (which turned out to be the field memory chips causing that). @THW can you try with the RGB output and advise if there are any issues there?

Looking at the schematics, the left and right mouse buttons go to Alice and the CIA (U350), but the POT_0X, and 0Y (as well as _1X and 1Y) signals go to Paula for the movement of the mouse (pins 35 & 36, and 38 & 39). The joystick signals (forward, back, left, and right) however go through U975.

Looking at the output of the RAM scan, it is identifying that bits 0-7, and 9-16 are all being held high. and this should be the first fault to fix. What machine are you building/repairing?

you can use the Prometheus board for the AA3k and not install the CPLD's and the PCI slots and it will then work as just a zorro daughterboard.

What is your 5v rail measuring during the points when you experience these issues?

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Given the issues that you're experiencing, I think there are some systemic issues with your particular build.

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Yes, the device name for the A4000 IDE is scsi.device. And there is not a lot to the IDE on the A4kTX, are you able to reflash the GAL's (U901, and U902)?

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Removing the burnt section of the trace will be a start and to then clean up the board. For the final repair, I use 0.4mm enamel copper wire (links from Jaycar and Altronics below) for the "bodge" wire to patch from one end to the other. The enamel can be burnt away at the ends with a...