20-040 X-ray source power supply LOCAL REMOTE switch

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The 20-040 X-ray source power supply is used on some of the older PHI X-ray photoelectron spectroscopy (XPS) systems. There is a switch on the back of the 20-040 that needs to be set to the LOCAL position. When in the LOCAL position the high voltage is set by the user but the 32-095 or 32-096 X-ray source control turns the 20-040 high voltage on and off. Sometimes the LOCAL / REMOTE switch can become oxidized in which case the 20-040 high voltage may not turn on. This post explains how to remove the LOCAL / REMOTE switch and hard wire the board to the LOCAL position.

20-040 front panel
20-040 front panel

Make sure that the 20-040 main power switch is OFF and then unplug all cables from the back of the 20-040 and remove the 20-040 from the electronics console.

Remove the top cover (8 cross head screws).

Unscrew the nut on the LOCAL / REMOTE switch and also unscrew the two nuts on the 15 pin connector. Unplug the 3 pin connector on the top of the board, the larger bottom connector can stay attached.

On the back of the little board that the LOCAL / REMOTE switch is attached to you can see where the switch is soldered to the board. Un-solder and remove the switch. A solder sucker works well but you can also use some solder wick.

Solder some jumper wires between the pins as shown in the image below.

20-040 board with jumpers installed

Reattach the 3 pin connector and then insert the 15 pin connector back into the slot and use the two nuts to attach the board to the back chassis. I also added a plastic screw and nut to block the hole that remains after removing the switch. You can also just leave that hole open.

Plastic nut
Hole plugged

Replace the cover and tighten the 8 cover screws.

Make sure that the 20-040 main power switch is still OFF and then insert the 20-040 back into the electronics console and reattach all the cables to the back of the 20-040.

Below is a table that shows the pin outs on the control cable that goes between the 32-095/6 and the 20-040.

Removing the LOCAL / REMOTE switch eliminates the switch as a cause of lack of high voltage with the 20-040. If your 20-040 does not work and can’t be repaired, then RBD Instruments provides a drop in replacement, the 20-042.


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