EMO box push button switches

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The EMO box (Emergency OFF) used on many PHI systems has switches that can become noisy, stick or fail to operate at all. These switches are used to turn on and off the card rack power, main electronics console power, vacuum console power, bakeout power and to turn off and reset all power.

Another very common issue is that the light bulbs in the switches tend to burn out on a yearly basis.  This blog post will describe where to get replacement parts for the EMO boxes.

The round red EMO button switch is still available but the original square push button switches that were produced by Cutler-Hammer (now Eaton) are very difficult to find. Honeywell equivalents are listed below.

There are two styles of EMO boxes.  The 32-005 style has a Bakeout switch and the other style has a Vacuum Console power switch.

EMO box
EMO box
32-005 EMO box
32-005 EMO box

Equivalent replacement switches produced by Honeywell are listed below.

EMO box switch
EMO box switch
EMO button McMaster-Carr PN 7403K42  
Main Power ON/Reset   Honeywell PN #: AML21CBA3AC
Allied Electronics Stock #: 70119090
Main Power / OFF Honeywell PN #: AML21CBA3AC
Allied Electronics Stock #: 70119090
Electronics  Console Power Honeywell PN #: AML21CBE2AD
Allied Electronics Stock #: 70119866
Vacuum Console Power Honeywell PN #: AML21CBE2AD
Allied Electronics Stock #: 70119866
Card rack power Honeywell PN #: AML21CBE2AD
Allied Electronics Stock #: 70119866
Bake Out Power Honeywell PN #: AML21CBE2AD
Allied Electronics Stock #: 70119866

Original lamp –

T1 3/4 Wedge lamp
T1 3/4 Wedge lamp

Lamp; Incandescent; T-1 3/4; Sub-Mini Wedge; 28V; 40mA; 0.3MSCP; 7000 Hrs

Manufacturer #: 85

Allied Stock #: 70013004

Recommended LED replacement lamp –

T1 3/4 LED wedge lamp
T1 3/4 LED wedge lamp

Lamp; LED; T-1 3/4; Sub-Mini Wedge; White; 28V; 40mA; 0.3MSCP; Lamp life 30,000 hours.

Manufacturer #: LED-24-T1.75 WEDGE-W Allied Stock #: 70012994

These LED lamps are more expensive but will last for almost 4 years compared to about 1 year for the regular tungsten lamps.

Mouser PN 560-LE-0509-01W is a white LED that would work for all of the switches and it costs less. Made by JKL Components https://www.mouser.com/datasheet/2/208/LE-0509-01-21680.pdf

Bonus – EMO box schematics are shown below

32-005 EMO box
32-005 EMO box
EMO box
EMO box

11-065 High Voltage Arcing problem and solution

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As the 11-065s get older we are starting to see instances where the beam voltage, condenser voltage or objective voltage becomes unstable as the front panel potentiometers are adjusted.

The front panel potentiometers can become “noisy” as a result of oxidation on the internal contacts.  In addition to causing instability in the output voltages, it is also possible for the potentiometer output potentiometer “open” up.  When this happens, the output of the beam, condenser or objective supply can go as high as 6.4kV as shown in the picture below in which a 1000:1 high voltage probe is used to measure the beam voltage supply.

In the case of the condenser or objective supplies becoming unstable the result is that the ion beam might go in and out of focus, or the ion beam can get completely shut off.  However, if the beam voltage becomes unstable and goes up to 6.5kV then the opto-couplers on the HV1 board will become damaged and then the emission or pressure circuits will no longer function properly.  The opto-couplers are only rated up to 5kV.

If you suspect that your 11-065 beam, condenser or objective supplies are unstable, here is how to test the HV1 board outputs;

  1. Turn off the 11-065 and unplug the input power cord.
  2. Place the 11-065 on the bench and remove the top cover
  3. Remove the HV cover (on the right hand side of the unit)
  4. Unplug all of the spade connectors which connect the various wires to the HV1 and HV2 boardsHV1 outputs
  5. Lift out the HV2 board (the one closer to the center of the unit)
  6. Place all of the wires off to the side of the 11-065, making sure that none of them touch the chassis. Most of the wires are outputs and so have no voltage on them, but the 4 center wires on the HV2 board have 20VAC on them.
  7. Connect a high voltage probe to the beam output connector on the still plugged in HV1 board, (the board closest to the chassis) ground reference is the chassis. The outputs are:   E93 Beam Voltage, E90 OBJ, E89 COND.Beam voltage HV1 board
  8. Plug in the 11-065 input power cord.
  9. Make sure that the Beam voltage switch is OFF and the beam voltage knob is turned fully CCW.
  10. Turn on the 11-065 power.
  11. Turn on the beam voltage and monitor the output on the DVM that is connected to the high voltage probe.
  12. Slowly turn the Beam voltage potentiometer CW and observe the DVM reading. The Beam voltage output should increase smoothly from near zero to 5kV as you turn up the potentiometer.  If you see jumping, instability, or if the Beam voltage output goes up to 6.5 kV then the potentiometer is noisy and needs to be replaced.  The potentiometer is a 10 k ohm 5 turn 2 Watt 1% potentiometer available from DIgikey, Mouser and Newark.  
  13. The OBJ and COND outputs go from 50% to 100% of the Beam Voltage.  So to test those, the Beam voltage needs to stay fully CW at 5.0   The OBJ and COND potentiometers are also 10 k ohm 5 turn 2 watt 1% potentiometers. 

If the Beam voltage potentiometer was noisy and the voltage went higher than 5kV, then the opto-couplers were likely damaged.   If your do not get any emission current, then most likely U6 on the HV2 board was damaged and should be replaced.  Other components may be damaged as well. If the emission works but not the pressure, U7 is likely damaged.

On the really old 11-065s, U6 was a TIL109 opto.  When that part became obsolete about 20 years ago, it was replaced with a SPX314 opto.  Most of the 11-065s in the field have been updated to the SPX314 (a modification is required).   If you have a really old 11-065 with the TIL109 opto-couplers, RBD still has a few of those in stock.

Recently, the SPX314 has become obsolete and is hard to find.  It can be replaced with a OPI 110 opto-coupler which is also has 15kV of isolation, so even if the HV1 board goes up to 6.4kV this opto-coupler will not get damaged. The OPI 110 will not only repair the problem, it will ensure that this particular problem does not happen again.

There is no modification required to switch from a SPX314 to an OPI 110, but the pin outs are slightly different and are shown in the pictures below.

SPX314 on HV2 board
11-065 opto
OPI 110 opto connections
OPI 110 connection info
U6 schematic HV2 board

The OPI 110 opto-couplers are available from most major electronic part suppliers including Mouser.

Here is a link to the datasheet – OPI 110 datasheet

If you need technical help to repair your 11-065 ion gun control you can contact RBD Instruments Inc. for assistance. We offer technical support, repair/ calibration and the use of a loaner 11-065 while your unit is being repaired.

11-010 Electron Gun Control modification to reduce noise

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Due to aging components, many of the PHI 11-010 5kV electron gun controls have developed a slight noise problem in the emission chopper circuit on the 623 board that results in about 300 mV of 60 hz ripple on the emission voltage, which translates into noise in the electron beam and Auger data.

Since the chopper circuit is never used (it was designed as a way to get N/E data with a lock-in recorder), a very simple solution to the problem is to bypass the chopper circuit.

Procedure:

  1. Unplug the 11-010 AC power cord and remove the cover.
  2. Solder a jumper between Pins 17 and 18 on the 623 board as shown below.  The 623 board is located on the side of the 11-010, just above the filament supply board.

This modification will reduce the noise level from about 300 mV to 50 mv or less and results in noticeably cleaner Auger data.

Chopper board resistors
This jumper will bypass the Chopper board circuitry
Chopper board schematic
Jumper location on Chopper board