Hastings RV-16D Vacuum Gauge Repair

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

Failed Resistors on RV-16D schematic

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 before repair

 

 

 

 

 

 

 

 

 

 

TC gauge after 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

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

Bonus

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

Installing repaired TC gauge into AVC

 

 

 

 

 

 

Repaired TC gauge inside AVC

Repaired TC gauge inside AVC

10mV and 4th bar

10mV and 4th bar

Soldering wires to front panel 10mV and 4th bar potentiometers

Soldering wires to front panel 10mV and 4th bar potentiometers

AVC Up to Air relay update

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

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

24V up to air relay

 

 

 

 

 

 

 

 

 

Updating an AVC to this relay is a simple two-step process;

  1. Replace the Up to Air relay in the AVC
  2. 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.

Pfeiffer Hi Cube 80 Eco

HiCube Eco 80

HiCube Eco 80

https://www.pfeiffer-vacuum.com/en/products/vacuum-generation/pumping-stations/turbo-pumping-stations/hicube-eco/?detailPdoId=20022

 

 

 

 

 

 

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

Here is the Cable Data Sheet ENG_CD_2273000_A1

On the controller you will need to set option 36  Configure the Accessory B1 to 0.  Then the up to air relay will energize when the turbo pump control turns the turbo pump on.

 

Edwards T station nETX85H

T station

T station

https://shop.edwardsvacuum.com/products/ts85d3002/view.aspx

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V4 Differential Valve Problem

V4 Differential Valve Problem

This post describes how to fix the problem of the V4 differential valve not opening on an AVC when the DIFFY PUMP ION GUN button on the AVC remote box is depressed.  Look at the photos at the bottom of the post for additional information.

The AVC (Auto Valve Control) has two DV6M thermocouple gauge tubes which are used to monitor the vacuum levels in the load lock and at the turbo pump. In the case of systems that have two turbo pumps, the second thermocouple gauge tube monitors the ion gun differential pumping turbo. The load lock TC gauge tube is located on under the load lock or in some cases as shown below, under the table top.

The AVC displays the vacuum level of the load lock thermocouple gauge at all times with the exception of when the DIFFY PUMP ION GUN button on the AVC remote box is depressed. In that case the AVC will momentarily monitor and display the turbo pump thermocouple gauge tube. If the vacuum level is sufficient then V4 will open. Monitoring the turbo pump vacuum is a built in safety feature of the AVC to prevent the chamber from being dumped in case the DIFFY PUMP ION GUN button on the AVC remote box is depressed while the turbo pump is off or not up to speed.

A not uncommon problem with the AVC unit is that the V4 valve will not open when the DIFFY PUMP ION GUN button on the AVC remote box is depressed.

The most common solution to this problem is that the turbo pump thermocouple gauge tube is not working properly or is not matched closely enough to the load lock gauge tube. Here is how you can test the ion gun gauge tube –

  1. Press the PUMP INTRO button on the AVC remote and pump out the load lock until you have 5 bars displayed on the AVC remote.
  2. On the back of the AVC (located on the back of the vacuum console), remove the TC1 gauge cable. TC1 monitors the load lock.
  3. Unplug the TC2 cable and move it into the J1 connector where you just unplugged TC1.
  4. Look at the AVC remote box. If the turbo pump thermocouple gauge is working properly you will see 4 bars displayed. After 2 minutes you should see 5 bars displayed.   If only 3 bars are displayed you can adjust the AVC so that V4 will open by following the steps in this older blog post – https://www.rbdinstruments.com/blog/auto-valve-control-adjustment-procedure/

If only 2 bars are displayed then the next step would be to try replacing the DV6M thermocouple gauge tube. There is only one TC controller (Hastings T6 called the hockey puck because of its shape) inside the AVC and a relay switches between the two thermocouple gauge tubes when the DIFFY PUMP ION GUN button on the AVC remote box is depressed. If the two thermocouple gauge tubes do not have similar offset and gain properties then the only solution is to replace the turbo pump DV6M thermocouple gauge tube or the intro thermocouple gauge tube in order to get them to match more closely. If the AVC reads 1 bars all the time then the hockey puck may be defective.

Usually though, the problem is that the thermocouple relay inside the AVC is not switching. Or the contacts on the relay may be dirty. In the case of the older Blue plastic relays it is common for the plastic switch throw to be cracked at the top in which case the relay may close but not all the way and so the turbo pump thermocouple gauge is not read at all.

If when you swapped TC1 and TC2 only one bar was displayed, then most likely the relay I broken or the contacts are dirty. Here is how to address that problem;

  1. The easiest way to get to the back of the AVC is to come in through the top. So, remove the wooden table tops and the aluminum ones that are towards the back of the vacuum console.
  2. Close all valves on the AVC and also turn off the turbo pump (s).
  3. Turn off the AVC control power.
  4. Remove cables from the back of the AVC, including the power cord.
  5. Unplug the air manifold cable and remove the gas manifold from the AVC (2 to 4 screws) The air-lines stay connected to the manifold and the compressed air that is connected the back of the vacuum chamber stays on..
  6. Remove the AVC control and unplug the 40 pin remote box ribbon cable.
  7. Place the AVC control on a work bench or table and remove the cover.
  8. Inspect the TC relay K3 (on older AVCs there are only 2 relays and the thermocouple gauge relay is the left one). If you have a newer AVC with 3 relays, the TC relay is the far left one. The far right one is the up to air relay. If it is the old blue relay you can remove the two mounting screws on the back of the AVC to make the relay more accessible.
  9. If the TC relay is the old Blue plastic type then most likely the relay contact pull piece is broken at the top. If you remove the cover you can inspect the top part of the pull piece and if it is cracked then the relay needs to be replaced. (You can also just move a new pull piece over from a new relay rather than unsolder the relay).
  10. If the TC relay is the newer style then most likely the contacts are oxidized and you will need to clean the contact with some fine sand paper or emery cloth followed by paper soaked in isopropanol to remove the residual small particles. (Or you can replace the relay with a new one).
  11. To clean the contacts, unplug the relay from the socket and remove it from the AVC.
  12. Remove the plastic cover from the relay (it snaps on so use small screwdriver to un snap it) then clean the contacts.
  13. You can measure the resistance on the contacts with an ohm meter and manually move the relay throw to switch between the two sets of contacts.
  14. Reinstall the relay.
  15. Reinstall the AVC control and reconnect the gas manifold and all the cables.

That should do it!   If not then please contact RBD Instruments Inc. for more assistance. We can repair your AVC controller and also provide DV6M thermocouple gauge tubes.

RBD Instruments Inc. www.rbdinstruments.com 541 330 0723

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