Hi Commodore,
Just dug out the manual for an M1230XA I used to have (my very first A1200 upgrade). Here's what it says about the two jumpers, located on the right hand end of the board near the FPU chip.
Jumper 1 (The one closer to the FPU)
If the CPU and FPU are the same speed (MHz), this jumper should short the RIGHTMOST pins. If the CPU and FPU have different speeds, the FPU will have its own oscillator and the jumper should short the LEFTMOST pins. Overclocking the FPU will damage the M1230XA.
Jumper 2 is a TEST jumper. Leave the jumper OFF (just hanging on one pin). When the jumper is across both pins, the configuration EEPROM is bypassed on boot and the XA's RAM setting is reported at 128Mb at the slowest cycle setting. The TEST jumper should be put on only if the EEPROM is inadvertantly in a 'confused' state. It is mainly used by the manufacturer when they configure the board.
Cheers, JaX
