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.
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.
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.
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.
