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I'm trying to install a 68060 accelerator on an Amiga 3000T, but I cannot figure out the correct jumper settings. The information I've found online is:

J100 CLK90 Delay jumper. This Jumper has three positions. In position 1-2 it sets up CLK90 for 25Mhz operation. In Position 2-3 CLK90 is set up for 16Mhz operation. In position 3-4 the EXT90 line drives CLK90, rather than the on-board clock logic.
J102 Board Clock. This jumper has two positions. In position 1-2 the sorce for CPUCLKa and CPUCLKb must be EXTCPU. In position 2-3 it shorts the 68030 and local bus clock sources, such that CPUCLKa and CPUCLKb and CLK30 all all derive from the same source, which is either EXTCPU or the clock based on the local logic, depending on the state of J104.
J103 FPU Chip select jumper. This jumper has three positions. In position 1-2 it disables the onboard FPU. In position 2-3 it causes the 68030 to get F-line traps instead of the FPU transaction and in position 3-4 it enables the onboard FPU.
J104 CPU CLOCK. This jumper has two positions. In position 1-2 the source for CLK30 is derived from the on-board clock generator. In position 2-3 the source for CLK30 must come from EXTCLK by by way of J102.
J105 System clock disable. In the 2-3 position this jumper allows DIS_CLKS line from the local bus slot to operate normally. In the 1-2 position it forces DIS_CLKS high (asserted) disabling on-board system clock generation.
J106 CLK90 short jumper. In the 2-3 position there are two versions of CLK90. The system normally runs this way. In the 1-2 position the two CLK90 lines are shorted toghether to allow a single line to source both clocks.
J107 68030 Clock disable. In the 2-3 position this jumper allows the DIS_CLK30 line from the local bus slot to operate normally. In the 1-2 position it forces DIS_CLK30 high (asserted) disabling on-board 68030 clock generation.

(From http://eab.abime.net/showthread.php?t=33474)

However, I don't know what that means. I'd rather not risk a 30 year old machine and an $800 board.

  • you can probably rule out a lot of jumpers that can't possibly damage the device. For instance "FPU Chip select jumper. This jumper has three positions. In position 1-2 it disables the onboard FPU. In position 2-3 it causes the 68030 to get F-line traps instead of the FPU transaction and in position 3-4 it enables the onboard FPU." this can't possibly damage the board. Overclocking is the main reason you can fry a chip. Is the board designed for A3000T? or some other model? – Jean-François Fabre May 27 at 9:24
  • Board is a new board that's been tested on 3000, 4000 and 4000T, but not the 3000T. Since the CPU connector should be the same for all four models, it should work on it (manufacturer confined that it should work prior to purchase), – Zenzizenzizenzic May 27 at 11:49
  • I would have thought it possible to map the A3000 jumper settings that work for your accelerator over to the A3000T. Could you specify what jumper(s) are not common between the 3000 and 3000T? – Brian H May 27 at 13:44
  • @BrianH, I don't have a 3000 desktop, but the jumpers are completely different. They are labeled "EXT" and "INT" and there are only three, not seven. – Zenzizenzizenzic May 27 at 20:15
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    You may need to embrace the experimentation route. I remember it taking some trial and error just to get correct jumper settings for an A3640 in an A3000 desktop, and that configuration is much more common. Only assumption I'd make is all the clock sources should probably be "external", meaning they come from the 060 card. You can confirm this if you know the correct jumper settings for A3000/A4000 desktops. – Brian H May 28 at 14:43

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