Overview:
The condenser and objective steering voltages in the 20-622 electron gun control used on the PHI 660 scanning auger systems need to be adjusted periodically (check it as part of preventive maintenance service) for optimal image stability.
If your image is stigmatic and moves a lot when you change your objective lens, you may want to check the condenser and objective steering voltages. A small amount of image movement is normal.
Following this procedure will ensure that the steering voltages are operating properly and also that they are properly balanced.
Summary Table:
| J3 Pin | Description | Offset Pot | Gain Pot | Deflection Bd. Pin | Lens Bd. Pin |
A |
COND X |
R 27 |
R 25 |
Defl 1 pin 8 | 58 |
| C | COND X | R 27 | R 25 | Defl 1 pin 10 | 58 |
| B | COND Y |
R 23 |
R 22 |
Defl 1 pin 62 | 50 |
| D | COND Y | R 23 | R 22 | Defl 1 pin 64 | 50 |
| E | OBJ X |
R 36 |
R 35 |
Defl II pin 7 | 66 |
| G | OBJ X | R36 | R 35 | Defl II pin 9 | 66 |
| F | OBJ Y |
R 34 |
R 33 |
Defl II pin 61 | 56 |
| H | OBJ Y | R 34 | R 33 | Defl II pin 63 | 56 |
Procedure:
- Turn OFF the 20-610 30kV High Voltage Supply.
- Remove the 20-622 from the electronic console and extend the Lens control card (second board from the top). Support the board so that it is level with a non-conductive object. Remove all cables going to the 20-622 except for the power and the 40 pin ribbon cable between the PC147.
- Connect a DVM between pins A and C on the J3 COND & OBJ Steering connector on the back of the 20-622.
- Turn on the 20-622 and in AugerMap set the Beam voltage to 10kV and also set the COND X steering to 50% (mid-range).
- Adjust R 27 on the lens control board for zero volts on the DVM.
- Set the COND X steering to 100% and adjust R 25 for 205.0 volts DC.
- Connect the DVM between pins B & D on J3.
- Set the COND Y steering to 50% and adjust R 23 for zero volts.
- Set the COND Y steering to 100% and adjust R 22 for 205.0 volts DC.
- Connect the DVM between pins E & G on J3.
- Set the OBJ X steering to 50% and adjust R 36 for zero volts.
- Set the OBJ X steering to 100% and adjust R 35 for 205.0 volts DC.
- Connect the DVM between pins F and H on J3.
- Set the OBJ Y steering to 50% and adjust R 34 for zero volts.
- Set the OBJ Y steering to 100% and adjust R33 for 205.0 volts DC.
- Set the COND X, COND Y, OBJ X and OBJ Y steering to 50%.
- Set the Beam Voltage to 3kV.
- Check each pin again with respect to the chassis. They should all be zero volts with-in 50 mV DC and be stable. If they are not stable, the 7541 Dacs or 208H opamps on the error control board are usually the problem.
Calibration Complete.
