Symptoms include: Sampling meters stuck and non-responsive, dead pad sensors, and no sound output.
The cause for all three of these symptoms is losing the -12V analog rail, so if only the pad sensors are dead then this fix does not apply.
Disclaimer: Take the proper static precautions, observe all electrical safety standards, and assume liability for any potential bodily injuries or property damage. Make a diagram of all removed parts, especially screw locations.
– Turn off and unplug the 2000XL. Disconnect the power cord from the MPC entirely, just to be safe!
– Remove the bottom metal panel of the 2000XL. Keep the removed screws somewhere safe.
– Find the six wire connector (grey with orange stripe) which runs from the power supply to the mainboard. There will be a ‘P1’ label printed next to where the connector plugs in on the mainboard.
– Unplug P1 by pinching its retention clip and pulling directly up by the plug itself, not the wiring.
– Beside the 8-output expansion connector, a tall wire arch should now be easily visible and accessible. This wire arch is a resistor with an ‘R1’ label printed right next to it. R1 is supposed to be light-colored with a four color band, so if it looks scorched and/or smells burnt then that indicates a likely problem.
– However, to be sure R1 is damaged, it is best to use an ohmmeter or multimeter to check the resistance of R1. The normal value of R1 is 4.7 ohms, so if R1 measures significantly higher (kilo/mega ohms, or has no continuity at all!) then R1 will need to be replaced with a new 4.7 ohm, 1 watt resistor.
Higher than 6 ohms = bad!
When sourcing a replacement part, make sure it is 1 watt, and not 1/4 watt. Make sure it is 4.7 ohms exactly. Do not confuse 4.7 ohms with other values such as: 4.7K, 4.7M, or 4k7. Also, make sure the resistor has axial leads for through-hole use, and is not a surface mount (SMD) type.
Mouser is available in most parts of the world, so KOA Speer brand carbon-film resistors (part #: 660-SPR1CT52R4R7J) should be easy to acquire, although there are many equally suitable parts from other suppliers such as Panasonic ERX-1SJ4R7.
