32-095 X-ray source control

Posted on February 28, 2017 by Randy

When the 32-095 X-ray source control is not working properly there are some easy possible solutions that you can check before sending the unit to RBD Instruments Inc. for repair.

If the problem is that one filament works but the other one does not, then you should check the fuses located on the filament power supply board inside the 32-095 X-ray source control in the back left hand corner of the unit. (The other possibility is that the x-ray source filament is open.) With the 32-095 power off, slide the unit out and remove the cover, then measure the resistance on the fuses. Usually it is easiest to just completely unplug the 32-095 and remove it from the electronics rack.

The fuses are 5 amp slow blow and are shown in the board layout figure below.

Filament power supply board fuses

The next most common problem is instability in the controller or flashing digits on the digital panel meter. These can be caused by high AC ripple on the +/-15V or +5 V supplies on the local power supply board which is located in the front left hand side of the 32-095.

The figure below shows the layout of the local power supply board and the location of the +/-15V and +5V supplies.

local power supply board layout

The picture below shows the points where you measure the +5v supply. To measure the +5V supply, connect your test clips to the pins as shown in the picture below. Turn on the 32-095 power and then measure both the DC and AC voltage using a DVM. The correct value is +5.0 V DC (+/- 100 mV) and the AC ripple should be less than 10mV. If the +5V supply has a problem the DC will be more like 4V and the AC will be 1 to 2V. Power supply board problems are usually caused by bad capacitors.

32-095 local power supply board +5V

The pictures below show the test points for the + and – 15V supplies. The correct voltage values are + and – 15.0V (+/- 200 mV) and the AC ripple should be less than 20mV. If the DC voltage is low and the AC ripple is high then the supply has a problem.

32-095 local power supply board -15V

32-095 local power supply board +15V

The figures below show the +5 and +/- 15V local power supply board schematics.

5V schematic

15 V schematic

Below is a table that lists common problems and possible solutions. Sometimes the problems are easy to fix, but often the problem may be a hard to find bad capacitor, diode or integrated circuit.

Problem	Possible solution
No current on one filament	Bad power supply board fuse, open filament on source
No filament current but fuse is OK	Bad PIC 645 regulator
Unstable operation	Bad capacitor on local power supply board

If the problem is not an easy fix then RBD Instruments can repair your 32-095/96 x-ray source control and also provide you with a loaner unit to use while we are repairing yours.

Additional test info:

04-500/548 X-Ray Source Filament Test

The following information is helpful in testing the condition of the filaments in 04-500 or 04-548 15 kV dual anode X-ray sources and in troubleshooting the 32-095 X-ray source control.

X-Ray Sources

On the big filament connector on the source, pins A and B (filament 1) and C and D (filament 2) should have less than 1 ohm of resistance. All pins should be open to ground.

The HV connector (anode) should be open to ground. Check that with the X-ray high voltage supply OFF and the HV cable to the source disconnected.

32-095 Test

Follow the 32-095 Outgas/Activate procedure in the 32-095 manual.

To bench check the 32-095, short pins A and B on the Pressure Interlock connector, and pins A and E on the Pump Control connector.

You can use two large paper clips as dummy loads when testing the filament current. Put the clips on the end of the cable or on the filament connector on the back of the 32-095.

High voltage switch connections:

V4 Differential Valve Problem

Posted on February 4, 2017 by Randy

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 –

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.
On the back of the AVC (located on the back of the vacuum console), remove the TC1 gauge cable. TC1 monitors the load lock.
Unplug the TC2 cable and move it into the J1 connector where you just unplugged TC1.
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 K3 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. The RBD Instruments part number for the blue/yellow K3 relay is PN K3AVC24RE.

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;

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.
Close all valves on the AVC and also turn off the turbo pump (s).
Turn off the AVC control power.
Remove cables from the back of the AVC, including the power cord.
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..
Remove the AVC control and unplug the 40 pin remote box ribbon cable.
Place the AVC control on a work bench or table and remove the cover.
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.
If the TC relay is the old Blue plastic type(RBD part number PN -K3AVC24RE), 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).
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).
To clean the contacts, unplug the relay from the socket and remove it from the AVC.
Remove the plastic cover from the relay (it snaps on so use small screwdriver to un snap it) then clean the contacts.
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.
Reinstall the relay.
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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Endoscopic ion pump inspection

Posted on January 30, 2017 by Randy

An easy way to determine whether or not an ion pump needs to be rebuilt is to perform an endoscopic ion pump inspection. The hard way is to drop the ion pumps.

In the last few years the prices have really come down on USB and android/iPhone endoscopes. If you do a search on EBay for USB endoscope you will see a lot of choices for under $20.00. The one used in this blog post is 7mm in diameter, which is small enough to fit into a 1.33” CF flange hole.

endoscope

endoscope_for_phone

For this example we inspected a PHI 660 scanning auger system equipped with a 220 l/s ion pump. This system has been in use for about 10 years primarily for depth profiling using Argon gas.

Since there is a shield below the TSP filaments the only way into the ion pumps was thru the un-used 1.33 CF flange that is opposite the ion pump high voltage connector.

This video link shows what it looks like as you move the endoscope around inside the ion pump – https://www.youtube.com/watch?v=5DQVW3DCG9A&feature=youtu.be Note that the video has a blue tint to if from the built in LED camera lighting.

The color corrected pictures below show that the ion pump elements are pitted, the insulating ceramics are coated and there are some flakes in the bottom of the pump well. The conclusion was that the pump elements have another year or so left on them and so we will plan on replacing them in 12 to 18 months.