32-100 Repair & Calibration

The 32-100 electron multiplier supply is used on many older PHI Auger and XPS surface analysis systems. This post has information about the 32-100 repair and calibration.

Command Structure

Use the diagnostic dialog box in Augerscan software to load the digital values per the 32-100 calibration procedure when calibrating the 32-100 in the digital mode.  CAUTION! Note that only personnel qualified to work safely with high voltage should perform these calibrations and tests.  Voltages of up to 5,000V DC are possible in the 32-100 electron multiplier supply.

Function                                               Command/Data(hex)

SEDVoltage                                       Addd

CMAVoltage                                       Cddd

Notes:   – the command and the data are combined in a 16 bit word

–  the left-most digit is most significant in address position and data value

–  “d” represents a data value in hex

– 000H = 0, 7FFH = 2047 (mid-scale), FFFH = 4095(max.)

Clear the CSR (= 0) for proper communication.

 Initial Setup

 Install a jumper wire on the back panel from IC (J7) to ground (J6). Note: if you do not do this, the CMA voltage will float (not referenced to chassis ground). Set the CMA and SED high voltage controls on the front panel completely counterclockwise and set the mode switches to “Off”. Disconnect P7 and P8 on the board.

DIP Switches:

• SW1: 1 and 4 closed
• SW2: 5 closed
• SW3: 1 closed
• all others open

Calibration

 Low Voltage  Power Supplies

Turn on the power. Do the following checks and adjustments with the reference to chassis ground. Always check for significant AC ripple on any DC power supplies.

Check for :

• +15Vdc onJ7-5
• -15Vdc onJ7-4
• +5Vdc onJ8-1

Make the following adjustments, checking for any significant AC ripple:

• Adjust R83 for 10.00Vdc on TP2.
• Adjust R79 for +17Vdc on P6-2.
• Adjust R9 for +300Vdc at E4.
• Adjust R22 for +300Vdc at E2. (Note, adjust this to 50V if you have a 20-805 or 20-810 control on an double pass XPS system)

Note that for the above measurements, the chassis is the ground reference.

SED HV Supply

Using a HV probe, measure the voltage at E3 for the following conditions. The reference is to chassis ground. Note: the bit number in () indicates the only bit set (=1), for troubleshooting purposes.

Start by calibrating the HV limit (AFFFH=3300V). Adjust R54 to calibrate. Verify that 3300V is also achieved by turning the SED HV control knob completely clockwise with the mode set to“Analog”.

Check for increasing voltage as you enter the following values in sequence: A000H, A00FH (bits 0-3), A010H (bit 4), A020H (bit 5), A040H (bit 6), A080H (bit 7).

CMA HV Supply

Using a HV probe, measure the voltage at E1 for the following conditions. The reference is to chassis ground. Remember to connect the jumper from J7 to J6 on the back panel.

Start by calibrating the HV limit (CFFFH=4000V). Adjust R62 to calibrate. Verify that 4000V is also achieved by turning the CMA HV control knob completely clockwise with the mode set to“Analog”.

Note: the bit number in () indicates the only bit set (=1), for troubleshooting purposes.

Check for increasing voltage as you enter the following values in sequence: C000H, C00FH (bits 0-3), C010H (bit 4), C020H (bit 5), C040H (bit 6), C080H (bit7).

Troubleshooting Tips

1. One of the first things to check is the +17Vdc power supply to the two TIP120 transistors when the 32-100 power is switched on. If it drops significantly (typically down to just a few volts), then the problem is likely one of the HV transformers (T1 or T2) or the clock. Disconnect jumpers J29 and J30 (short wires next to the TIP120s). Turn on the 32-100 power and check for clock pulses at TP8, TP9, TP10, and TP11. If the clock is not detectable at any or all of these test points, then there is a problem in the clock circuitry. If the clock is okay, then test each transformer one at a time by connecting one of the jumpers, turning on the 32-100 power, and noting if the +17Vdc supply drops. Replace the transformer if it causes the +17Vdc supply to drop when its jumper is connected (J29 for the SED and J30 for the CMA).
2. Another common problem involves the low voltage circuitry for each supply (drivers for E2 and E4). If these points are not at 300Vdc and cannot be adjusted, then the problem lies here. The most likely components to fail are the diodes, especially the 1N970s (CR19 and CR27).
3. Commonly needed repair parts:

Transistors: TIP50, TIP120, MPF108, 2N3904

Diodes: 1N970A, 1N972A,1N459A

CAUTION! Note that only personnel qualified to work safely with high voltage should perform these calibrations and tests.  Voltages of up to 5,000V DC are possible in the 32-100 electron multiplier supply.

If you are unable to perform these tests RBD Instruments can repair your 32-100 electron multiplier supply and also provide a loaner unit if needed.