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This procedure describes how to replace the solenoids in the Auto Valve Controller (AVC) used on Physical Electronics PHI surface analysis systems such as XPS Photo-electron and scanning Auger electron spectrometers.
The AVC provides control of the pneumatic valves on the system by using 24V DC solenoids to route air to either open or close the valves as needed. The symptom for a failed solenoid valve is that the light on the AVC remote box indicates that the valve is open, but the actual valve does not open. Or, it may be that the valve will not close.
The function of each valve is listed below:
Gate valve – Isolates load lock from main vacuum chamber
Vent valve – Isolates nitrogen back-fill from load lock
Isolation valve – Isolates turbo pump from load lock
Differential pumping valve – Isolates turbo pump from ion gun
Vent valve – Isolates nitrogen from turbo pump
Pre-pump valve – Isolates mechanical pump from load lock
There are two ways to test the solenoids;
1. Remove the air line (s) to the suspect pneumatic valve and open/close the valve manually. Some valves have two air lines and some have only one. In the case of two air line valves (typically V1 and V4) air should come out of the top air line to the valve when closed, and the bottom airline on the valve when open. If the AVC remote box indicates that the valve is changing states but the air does not change, then the solenoid is most likely bad.
2. You can remove the P10 cable plug from the back of the AVC measure the 24V DC voltage between the pins for the valve in question as shown in the table below. When ON, you will have 24V DC between the two pins for the solenoid in question.
Before you remove the P10 cable you need to close all valves on the AVC remote (V1, V2, V3 and V4) and turn off the turbo pump (s). Also turn off the air to the AVC manifold on the back of the electronic or vacuum console. Usually the air is connected to the console with a quick connect fitting. See Important Notes before turning off the air.
AVC solenoid wire connector info
When a solenoid is not working properly it is possible and even likely that the vacuum chamber can come up to air during the solenoid replacement procedure.
It is recommended that all valves be closed and the turbo pump(s) turned off before proceeding with the replacement of a solenoid. Note that even though the AVC remote may indicate that a valve is closed, if the solenoid is defective the valve may not actually be closed.
In addition to turning off the turbo pumps, also turn off the card rack power, all electronics, the ion gauge and the ion pump control.
Finally, before proceeding with the replacement of a solenoid, unplug or turn off the air to the back of the vacuum console. Most valves will hold their state (closed) with no air supplied to the valve, but marginal valves may leak when the air is shut off.
Solenoid replacement procedure:
Close all valves on the AVC
Turn off the turbo pump(s)
Turn off the ion gun, electron gun and X-ray source controllers
Turn off the card rack power
Turn off the DIGIII ion gauge control
Turn off the Boostivac ion pump controller
Turn off the AVC main power
Turn off or unplug the air to the back of the console
Unscrew the front panel AVC screws and slide out the AVC controller a little bit
Unscrew the air manifold screws so that you can access the solenoid screws
Unscrew the solenoid that you want to replace. The V1 solenoid is a little bit higher than the other ones and it is located at one end of the air manifold. Starting with the V1 solenoid, the order is V1, V2, V3, V4, V5 and V6.
Cut the wires to the existing solenoid. Make sure that you have enough length for when you reconnect the wires to the new solenoid. Note that the V1 solenoid has 2 sets of wires, upper coil and lower coil. Make sure that you keep the upper coil label on the wires so that you can connect the new solenoid upper coil wires to the correct set.
Cut the wires on the new solenoid to length and strip the ends on the wires that went to the old solenoid and also on the ends of the new solenoid.
Connect the wires together. White to white, black to black (except for V2 which has a yellow wire). You can use twist connects, in line crimp connectors or solder and heat shrink.
Screw the new solenoid into the manifold. Make sure that the black seals on the solenoid line up with the holes in the manifold. Snug the solenoid down firmly but do not over tighten the screws as the manifold is aluminum and it is easy to strip the manifold.
Use tie wraps to tidy up all the wires
Reattach the air manifold to the AVC controller
Make sure that all of the wires on the back of the AVC controller are still connected properly.
Use the front panel screws to reattach the AVC controller to the console.
Turn on the AVC controller main power. All valves on the AVC remote should indicate closed.
Reconnect the air to the back of the console.
Next, see if the ion pump control starts and stays on in the Run mode. If so, the system is still under vacuum.
Turn on the DIGIII ion gauge control and press the I/T 3 button to turn on the ion gauge.
If the ion pumps started and the ion gauge turned on, you should be back in business and can turn on the turbo pump (s) and use the system as you would normally.
If the ion pump control does not start then the system is up to air or partiality up to air. To test the condition of the vacuum inside the chamber, you can pump on the load lock until you have 5 bars and them manually close V3 and manually open and immediately close V1. That will equalize the vacuum in the load lock with the chamber. Now check how many bars you have on the AVC remote box. If 3 or 4 bars then the chamber is only partial up to air and you can just open V3 and V1 and rough the chamber out for 10 to 15 minutes to get into the 10-6 Torr range and then start the ion pumps.Close V1 once the ion pumps start.
If you only have one bar, then the chamber is likely up to air and you should bring the chamber up all the way by back filling with Nitrogen and then pumping the chamber back down. Those procedures are detailed at the bottom of this blog post.
If you have a leaking solenoid and need a replacement, RBD Instruments provides them and our part numbers are listed below. Please contact us for a quotation.
RBD AVC Solenoid part numbers
RBD part number
AVC solenoid designation
V1 24V Solenoid/Auto Valve Control
V2 24V Solenoid/Auto Valve Control
V3, V4, V5, V6 24V Solenoid/Auto Valve Control
V3, V4, V5, V6
New Style Humphreys Solenoid Info:
V3, V4, V6, V7 HA110-4E1
If you need to bring the vacuum chamber all the way up to air, here is the procedure –
System up to air procedure
This procedure will allow you to safely bring the 660 scanning auger system up to air for maintenance.
Shut down all electron, ion and X-ray source power supplies.
Turn off the card rack power
If V4 is open, close it by pressing the Diff Pump Ion Gun button on the AVC remote.
Pump the intro. If you need
Turn off the DIGIII ion gauge.
Turn off the Ion pump control and Boostivac control.
Allow the system to cool for at least 30 minutes. (Or just a few minutes if the electron gun was not on.)
Make sure that the turbo pump is on. If you have more than one turbo pump, they both need to be on.
With the turbo pump on and the intro still being pumped, depress the Backfill Chamber button on the Auto Valve control located behind the vacuum console.
You will hear a hissing sound as air is back-filled into the chamber.
Slightly loosen the intro hatch cover so that when the system is pressurized it will open.
Once the system is vented, turn OFF the turbo pump(s).
System Pump Down procedure
This procedure will allow you to safely pump down the system after being up to air for maintenance.
Make sure that all flanges are secured (use new copper gaskets whenever removing and replacing optics on the vacuum chamber).
With the turbo pump(s) off, depress the Rough Chamber button on the Auto Valve control located behind the vacuum console.
Make sure that the intro hatch is closed.
Turn on the turbo pump(s) by depressing the pumping unit button. You will hear the V2 valve close and the V3 and V4 valves open and the turbo(s) will begin to pump the system out.
After about 20 minutes you should have 5 bars on the Auto Valve control remote. Once you have 5 bars, cycle each of the 4 titanium sublimation filaments for about 2 minutes each at 50 amps on the Boostivac control.
Cycle each filament 2 times, with a few minutes of cool down time between filaments.
After all 4 filaments have been out-gassed, make sure that you still have 5 bars on the Auto valve control remote and then turn on the DIGIII by turning the power switch to UHV and depressing the I/T 3 button.
The DIGIII should indicate in the low 10-3 to mid 10-4 range. Allow the turbo to pump until the system pressure is in the low 10-4 to high 10-5 range, about 30 additional minutes.
Cycle the #1 titanium sublimation filament for about 2 minutes at 50 amps. (Note: If a TSP filament can no longer get at least 45 amps, use the next filament).
When the vacuum is in the low 10-5 range, start the ion pump control by turning the Mode switch to Start. Monitor the 10KV scale. The voltage should be increasing (maximum is about 5.5 kV), and the DIGIII should indicate that the vacuum is dropping into the 10-6 range. (Note that the meter on the Boostivac does not always read, if not then just make sure that you are in the 10-6 range and dropping on the ion gauge).
Once the DIGIII indicates the high 10-6 range, close the V1 valve by depressing the Rough Chamber button on the Auto Valve control located behind the vacuum console one more time. You will hear the V1, V3 and V4 valves close.
On the Auto valve control remote, depress the Diff Pump Ion Gun button to differentially pump the ion gun.
The system vacuum will continue to improve over the next few hours. Cycle the #1 titanium sublimation filament every 30 to 45 minutes to help the ion pumps pull the vacuum down.
Once the base pressure is in the low 10-7 to mid 10-8 range, the system can be baked out to obtain the best possible base pressure.
The Hastings RV-16D thermocouple vacuum gauge is used in the Physical Electronics’ (PHI) Auto Valve Control (AVC) to read the vacuum in the load lock and also at the turbo pump. There are two DV-6M thermocouple sensor tubes connected to the back of the AVC and a relay selects which one is routed to the RV-16D vacuum gauge.
The 0 to 10mV output of the RV-16D (also called the “Hockey Puck” ) goes to a comparator circuit in the AVC and is ultimately displayed on a LED segment graph on the AVC remote. One bar on the AVC remote indicates up to air and 5 bars indicates less than 5 X 10-3 Torr.
When the Hockey Puck in the AVC fails, it is usually because one of the DV-6M thermocouple sensor tubes failed and in turn some of the resistors inside the RV-16D overheated. This blog post will show you how to repair the RV-16D by replacing those failed resistors with higher wattage ones that should be able to survive the next time one of the DV-6M gauges fail.
The layout and schematic below show the resistors that usually fail. R 3 is a 15K ohm 2 watt resistor and R 4 is a 100 ohm 1/2 watt resistor.
Failed Resistors on RV-16D
Failed Resistors on RV-16D schematic
It is recommended that when you replace these resistors that you increase the wattage. For the repairs in the photos below, I used a 15K ohm 5 watt resistor and a 100 ohm 2 watt resistor. These resistors are readily available from Digikey, Newark and Mouser.
And since I already had the RV-16D torn apart I also replaced the capacitor C1 with a new one.
TC gauge before repair
TC gauge after repair
When working on the RV-16D be sure to completely unplug the power to the AVC. I recommend pulling the AVC completely out of the electronic rack or vacuum console. The RV-16D is located in the back left hand corner of the AVC. If your RV-16D has the metal cover on it you will need to remove it and either cut it around the wires or un-solder the wires an feed them through the case. Use your cell phone and take some pictures for reference before you un-solder any wires so that you can be sure to put them back in the exact same place. You do not need to replace the cover, the RV-16D will run cooler without it.
One final note. The schematic is not 100% correct as there is a 49 ohm resistor that is tied across the output on most of the RV-16D gauges that I have pulled apart. I think that this resistor replaces R5 and R6 as R6 is not needed since only the 10mV recorder output is used in the PHI AVC. If your RV-16D does not have the 49 ohm resistor, then I recommend that you add one. It will help to stabilize the output.
49 ohm resistor
If you need technical assistance or parts for the AVC or replacement DV-6M tube please contact us by creating a sales ticket here – RBD Portal Sales
Since the AVC was out anyway, I replaced the pots from the RV-16D (R1 , 1 K ohm) and also the bar adjustment pot in the AVC ( R 103 / K6 25 K ohm) to the AVC front panel with 10 turn 2 watt precision potentiometers and also installed an isolated BNC connector to the RV-16D recorder output wires (Blue and black).
This modification makes it much easier to adjust the RV-16D recorder output when you install a new DV-6M tube and to adjust the AVC for 4 bars when the load lock is pump out. The 5th bar on the AVC remote is on a timer and will turn on after the 4th bar stays on for 2 minutes.
With this modification installed it is not necessary to remove the AVC cover to adjust the hockey puck output or the AVC 4th bar.
Installing repaired TC gauge into AVC
Repaired TC gauge inside AVC
10mV and 4th bar
Soldering wires to front panel 10mV and 4th bar potentiometers
The Auto Valve Controller (AVC) is used to open and close valves on PHI surface analysis systems such as the 5000 series XPS and 660 scanning Auger systems. The AVC has a small built in microprocessor and so it also has the ability to protect the user from inadvertently opening a valve out of sequence and dumping the system.
The AVC needs to know that the turbo pump is on before certain valve functions are available. For example the V4 ion gun differential pump valve will not open under any circumstance if the turbo pump is not on.
So, how does the AVC know that the turbo pump is on? The Up to Air relay in the AVC auto valve controller is energized by a voltage from the turbo pump controller.
Up to Air relay inside AVC
When the AVC was designed PHI used Balzers (now Pfeifers) turbo pumps which had a 240 VAC output voltage when the turbo pump controller was ON. So, the Up to Air relay in most AVCs has a 240VAC coil.
Fast forward to today and some of those original Balzers/Pfeifers turbo pumps and controllers are now obsolete. So when one of those controllers fails, it needs to be replaced with a new state of the art turbo pump and controller.
These days most turbo pump controllers have a 24 V DC output voltage that can be used to control the AVC up to air relay. Both Edwards and Pfeifers have low cost replacement packages that are 4.5” CF flange mounted and also dry pumped backed. See information on those pumps at the bottom of this post.
The direct replacement 24 V DC Up to Air relay is Grainger part number 1YCZ6. This relay is the same form factor as the original Up to Air relay only it has a 24V DC coil instead of a 240 VAC coil.
24V up to air relay
Updating an AVC to this relay is a simple two-step process;
Replace the Up to Air relay in the AVC
Connect the Up to Air cable to the new turbo pump controller.
To replace the Up to Air relay in the AVC first make sure that all valves are closed and that the turbo pump is OFF.
Turn OFF the AVC and also unplug the power from the back of the AVC control. Depending on your system configuration the AVC is located in the front left hand side of the electronics console, or in the back of the vacuum console.
If the solenoid manifold is located on top of the AVC, remove the screws that hold the manifold to the cover and then remove the cover from the AVC. You should be able to move the solenoid manifold towards the back of the AVC and not need to unplug the wire bulkhead connector. Just balance the manifold on the edge of the AVC chassis.
If your AVC has the solenoid manifold mounted on the back of the AVC, then just remove the AVC cover.
Slide the AVC out enough so that you can get at the screws which mount the Up to Air relay to the side of the AVC. The Up to Air relay is located on the right hand side of the AVC chassis.
Make a drawing or use your phone and take a picture of the connections to the Up to Air relay to make sure that you put the connectors on the same way when you install the new relay. Remove the 240 VAC Up to Air relay bracket and install the new 24V DC relay.
Reattach the relay bracket to the side of the AVC.
Reattach the cover and solenoid manifold.
Reattach the power cord and slide the AVC back in.
Next, you need to attach the Up to Air cable to the new turbo pump controller. Refer to the turbo pump manual for information on how to make that connection. There will be a Setpoint output or some kind of external status connection that provides 24V DC when the turbo pump is ON.
Note the polarity of the wires on the Up to Air cable. On the end that plugs into the back of the AVC, the larger connector is the negative (ground) wire and the smaller one is the positive (+24V) connector. There are only two wires in the Up to Air cable. Red is positive and Black is ground.
If your turbo pump controller has some other voltage for the status signal (such as 12V or 5 V DC) then you will need to find a version of the Up to Air relay with that same voltage.
Once the new Up to Air relay modification is complete then you should hear the V5 vent solenoid click when the turbo pump is turned ON.
The V5 vent valve is designed to vent the turbo pump in order to prevent back-streaming of oil vapors into the system in the event of a system dump. When the AVC was first designed the backing pumps were all rotary vane mechanical pumps that used oil.
New state-of-the-art turbo pumps are typically backed with a dry pump and also have built in vent valves. If your new turbo pump is also dry backed (both of the turbo pumps listed below are then you do not need the V5 vent function.
The V5 vent valve was mounted on the rough side of the old turbo pump. If your new turbo pump is dry backed all you need to do to disable the V5 vent valve is to close the little needle valve that is either on the V5 vent valve itself or on the solenoid manifold near the V5 vent solenoid. (The largest solenoid is V1 and then you count out from there, V2, V3….)
If your new turbo pump is backed with a rotary vane oil pump then the V5 vent valve still needs to be connected to the rough line. The V5 needle valve is set to 1/4 turn CCW from the fully closed (full CW) position.
In addition, you want to make sure that the mechanical pump turns OFF when the turbo pump is turned OFF. If you need help with that contact RBD Instruments.
The affordably priced turbo pumps below can replace the original Balzers TPU 040 thru TPU 062 turbo pumps on older PHI surface analysis systems. If you order one, make sure that you order it with a 4.5” CF flange. A 4.5” CF flange will make it easier to adapt the new turbo to the existing vacuum connections.
If you get one of the Pfeiffer Cubes then this is the cable that you will need to connect to the Up to Air connector on the back of the AVC – Digikey PN A120881-ND made by TE and the TE PN is 22730001-1