20-622 calibration

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Below are the DR11 commands use in the 20-622 calibration procedure. The 20-622 electron gun control is used on the Physical Electronics 660 scanning auger systems.

Command Structure

Use DR11 program or RBD 147 diagnostics  for computer control.

Function                                               Command/Data (hex)

Beam Voltage                                      1ddd

Emission                                             2ddd

Objective Lens                                     3ddd

Iso. Objective Lens                              4ddd

Obj Y                                                  5ddd

Obj X                                                   6ddd

Cond Y                                               7ddd

Cond X                                                8ddd

Reset Overcurrent                                9ddd

Cond Lens                                           Addd

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)

Set the CSR (= 1) for proper communication.

Calibration

 Beam Voltage and Emission

Take the readings from the High Voltage (HV) Programming connector on the back panel. The Beam Voltage reading is taken from pin A and the Emission reading is taken from pin B. The reference is to chassis ground. Note: the bit number in () indicates the only bit set (=1), for troubleshooting purposes.

Command/Data  BV ctrl voltage (V)

1000H                                .001

1100H   (bit 8)                     .625

1200H   (bit 9)                     1.25

1400H   (bit 10)                   2.50

1800H   (bit 11)                   5.00

1C00H                               7.50

1FFFH                              10.00

Check for increasing voltage as you enter the following values in sequence: 1000H, 100FH (bits 0-3), 1010H (bit 4), 1020H (bit 5), 1040H (bit 6), 1080H (bit 7).

Command/Data  Emission ctrl voltage (V)

2000H                                 .001

2100H   (bit 8)                      .625

2200H   (bit 9)                      1.25

2400H   (bit 10)                    2.50

2800H   (bit 11)                    5.00

2C00H                                7.50

2FFFH                               10.00

Check for increasing voltage as you enter the following values in sequence: 2000H, 200FH (bits 0-3), 2010H (bit 4), 2020H (bit 5), 2040H (bit 6), 2080H (bit 7).

Condenser and Objective Lenses

A 200 ohm 2W 10-turn potentiometer must be connected to the Objective Fine Adjustment connector on the back before checking the voltages (Unless it is connected in the electronics bay) . Connect pin D to the pot wiper and connect pins A and C to the pot limits (either order). Set the pot to midway (5 turns for a 10-turn pot).

Note: the bit number in () indicates the only bit set (=1), for troubleshooting purposes. The voltages across the resistors (RX) are taken behind the front panel.

Iso. Objective

 Command/Data  R1-R6 Voltage (V)

4000H                                .016

4100H   (bit 8)                     .304

4200H   (bit 9)                      .610

4400H   (bit 10)                    1.22

4600H                                 1.83

4800H   (bit 11)                     2.44

4A00H                                 3.05

4C00H                                 3.66

4F00H                                 4.58

4FFFH                                 4.88

Check for increasing voltage as you enter the following values in sequence: 4000H, 400FH (bits 0-3), 4010H (bit 4), 4020H (bit 5), 4040H (bit 6), 4080H (bit 7).

Objective

Command/Data  R7-R10 Voltage (V)

3000H                                 .021

3100H   (bit 8)                     .322

3200H   (bit 9)                     .645

3400H   (bit 10)                   1.29

3600H                                1.94

3800H   (bit 11)                   2.58

3A00H                               3.23

3C00H                               3.88

3F00H                               4.85

3FFFH                              5.17

Check for increasing voltage as you enter the following values in sequence: 3000H, 300FH (bits 0-3), 3010H (bit 4), 3020H (bit 5), 3040H (bit 6), 3080H (bit 7).

Condenser

Command/Data  R11-R14 Voltage (V)

A000H                                 .018

A100H (bit 8)                       .469

A200H   (bit 9)                     .939

A400H   (bit 10)                   1.88

A600H                                 2.82

A800H   (bit 11)                     3.76

AA00H                                  4.70

AC00H                                  5.64

AF00H                                  7.05

AFFFH                                  7.50

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).

Steering

Check for proper centering of the voltages at the Objective and Condenser Steering connector on the back panel.

Command/Data  Between pins, Voltage (V)

57FFH                                   F&H, 0V +/- .4V                  Obj. Y

67FFH                                   E&G, 0V +/- .4V                  Obj. X

77FFH                                   B&D, 0V +/- .4V                  Cond. Y

87FFH                                   A&C, 0V +/- .4V                  Cond. X

20-622 System Test

It is possible for a 20-620 or 20-622 to work on the bench but not focus properly on a system. That is because on the bench the Objective and ISO Objective supplies are tested separately but on the system the objective coil is actually two coils which are tied together. So one of the objective supplies may cave in when connected to the objective coil. You can do a quick test by measuring the voltage across the current resistors behind the front panel of the 20-622 or 20-620.

Voltages for the 20-622 are listed below. The 20-620 should show a similar trend.

20-622   3kV Beam voltage, COND set to 35%, OBJ set to 74.49%, and Objective fine pot set to midrange.

COND.856
OBJ3.68
ISO OBJ3.69

20-622   5kV Beam voltage, COND set to 35%, OBJ set to 83.49%, and Objective fine pot set to midrange.

COND1.076
OBJ3.85
ISO OBJ3.47

20-622 Coil voltage supply test points

There are three coil voltage supplies in the 20-622:

Condenser 30V DC

Objective 34.5V DC

Isolated Objective 40V DC

To measure the supplies, remove the 4 screws on the 20-622 front panel and drop the front panel down (it is on a hinge).

There are three fuses visible on the front center of the heat sink assembly.

The top fuse is the Condenser supply, and it has a value of 1.5A slow blow.  Measure from either side of the fuse to the chassis and there should be approximately 30 V DC when the 20-622 main power is turned ON.

The center fuse is the Objective supply, and it has a value of 2A slow blow.  Measure from either side of the fuse to the chassis and there should be approximately 34.5 V DC when the 20-622 main power is turned ON.

The bottom fuse is the isolated Objective supply, and it has a value of 2.5A slow blow.  Measure from either side of the fuse to the ISO Objective test point (white wire) near the far-right hand current sense resistors. There be approximately 40 V DC when the 20-622 main power is turned ON.

The picture below shows the ISO Objective test point location.

ISO obj test point 20-622
ISO obj test point 20-622
Lens voltage supplies schematic
Lens voltage supplies schematic
20-622 OBJ Fine Jumper pins

Obsolete PHI units

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Obsolete PHI units

As many of you may know, RBD Instruments has been providing repair services and parts for old Physical Electronics (PHI) surface analysis systems and components for over 26 years. In fact, some of the electronic and optic units that we work on are over 45 years old!

As a result of aging electronic components in some of the very old units, or a lack of demand, we are discontinuing service on some PHI electronics and optics.

Where possible, in the list below we will offer newer alternative units as replacements.   We will also offer technical support if you want to try and repair the unit yourself. With our pricing model that has a cap on the maximum labor charge for electronics and optics it is not economically viable for us to repair these really old units. And if we were to charge the actual time that it may take to repair them, then that would not make fiscal sense for you as it may be less expensive to replace it with a newer unit.

The good news is that RBD Instruments still provides repair services and parts for most older PHI surface analysis systems and components.

Here is the list of obsolete PHI units:

Electronics:

96 V/F preamplifier (We still work on the 96A and 96B)

11-010 Electron gun control (Gray faced units, we still work on the Brown faced units)

11-055 analyzer control

11-500 Analyzer control (Gray faced units, we still work on the Brown faced units)

11-067 Ion gun control

11-069 DP scan control

18-040 10kV X-ray source high voltage control

18-080 Electron gun control

18-085 Electron gun control

18-600 Balzers Quad control

20-005 2kV ion gun control

20-095 X-ray source control

77-067 Ion gun control

PC137A Interface card

 

Optics:

04-151 10 kV X-ray source

04-300 ion gun

10-540 Manipulator

15-600 specimen stage

 

72-100 voltage

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I recently encountered an unusual problem on two different 660 scanning auger systems within a period of a few months where the 72-100 multiplier voltage would drop off after a period of time.

On one system the 97 SED preamp would fail after a few minutes of warm up time, resulting in no image. On the other system the 96A V/F preamplifier would fail after 20 to 30 minutes, resulting in no AES data.

In both cases I measured the multiplier supply voltages at the preamp and the voltages were there when functioning and not there or unstable when in the failed mode. So easy enough, that should be a problem on the 72-100 board. To verify that the problem was on the board I swapped the 72-100 board with the other one. For those of you not familiar with the 660 scanning auger system or the 72-100 electron multiplier supply, there are two 72-100s on a 660. One is for the CMA AES analyzer and the other one is for the 97 SED preamplifier. The boards are identical and can be swapped out by physically moving the boards and changing an address switch.

Swapping the 72-100 boards produced the same result. That meant that the problem was not on the board, so the next most likely thing was the SHV multiplier supply cable. Those cables checked out fine with an ohmmeter but to be sure I also swapped the cables out and the problem was still there.

So as unlikely as it was, the only thing left was the 72-100 mother board.   I pulled out the mother board looking for a bent pin or something that could explain the problem and did in fact find that one of the 1K ohm filter resistors was out of spec and looked like it had been running hot. Moving it slightly caused the resistor to break in two.

Here is a picture of the motherboard that shows the resistor:

72-100 R1 R2

72-100 R1 R2

And here is the schematic that shows both resistors:

72-100 mother board schematic

72-100 mother board schematic

Replacing the defective resistor solved the problem. What was interesting for me with this problem was that in over 37 years of working with PHI surface analysis systems I had never seen this problem before, and then I saw the same problem on two different systems within a short period of time.

If you have an intermittent SED image or AES data problem on your 660 (or 4000 series) scanning auger system, keep this solution in mind as something to check.