32-100 electron multiplier supply digital mode

Print Friendly, PDF & Email

The model 32-100 electron multiplier supply is used on older Physical Electronics Auger electron spectroscopy and X-ray photoelectron spectroscopy surface analysis systems to control the electron multiplier voltage.

When using the 32-100 electron multiplier supply in the digital mode (the software automatically sets the electron multiplier voltage)  the auto-ems box in the Auger Scan software AES electron multiplier properties dialog box needs to be checked, and the CMA multiplier switch on the front panel of the 32-100 must be set to digital.

But what if the 32-100 still does not work in the digital mode?  In that case, there may be a problem with one of the digital ICs.  The following procedure explains how to try and repair this problem.

  1. Turn off the 32-100 and remove the cover.
  2. Most 32-100s have three ICs for the SED digital side of the control which are not used. You can move those ICs over to the CMA side of the control and see if that solves the problem.
  3. Remove ICs U2, U4 and U6. These are the CMA digital ICs. Then, move over U3, U5 and U7 from the SED side if those chips are available. If they are missing, then you will need to order some of those ICs from Digikey, Newark or RBD Instruments. U2 and U4 are 74LS174s and U6 is an AD7521.
  4. If you did have those ICs and that did not solve the problem, then it most likely means that one of the encoder circuit ICs are defective. Those are U16 (74123) and U1 (AM25LS2538). RBD Instruments provides these parts.
  5. You do not need to replace the SED digital ICs as they are not used.

It is assumed that the 32-100 is working in the analog mode. If the 32-100 is not working in the analog mode it will not work in the digital mode either.

Refer to the pictures below for the locations of the ICs on the 32-100 motherboard.

Note that the switch positions need to be set as shown below.

 

32100-switch-positions

32100-switch-positions

 

If you need further help troubleshooting your 32-100 electron multiplier supply please contact RBD Instruments dot com

This slideshow requires JavaScript.

Leave a Reply

Your email address will not be published. Required fields are marked *