{"id":1173,"date":"2014-07-04T10:38:06","date_gmt":"2014-07-04T17:38:06","guid":{"rendered":"http:\/\/www.rbdinstruments.com\/blog\/?p=1173"},"modified":"2014-11-06T09:48:05","modified_gmt":"2014-11-06T17:48:05","slug":"auto-valve-control-adjustment-procedure","status":"publish","type":"post","link":"https:\/\/www.rbdinstruments.com\/blog\/auto-valve-control-adjustment-procedure\/","title":{"rendered":"Auto Valve Control adjustment procedure"},"content":{"rendered":"
The Auto Valve Control (AVC) controls all of the air valves on many PHI systems. It has built in logic that uses two thermocouple sensors and a mechanical switch to determine the status of the system.<\/p>\n
There are four common problems with the AVC: <\/strong><\/p>\n
1. The V4 ion gun valve will not open in the automatic mode.<\/p>\n
2. The gate valve will not close when the probe is retracted.<\/p>\n
3. The V1 led on the remote is neither Red (closed) nor Green (open).<\/p>\n
4. One or more of the solenoids stick, or leak.<\/p>\n
Problems\/Solutions: <\/strong><\/p>\n
1. The V4 ion gun valve will not open in the Automatic mode. <\/strong><\/p>\n
There are two thermocouple gauge tubes that sense the vacuum of the turbo(s), but only one TC gauge. TC1 is located on top of the turbo and determines whether or not the turbo pump is up to full speed. TC2 is under the tabletop and measures the vacuum in the intro chamber. If the intro pumps down to 5 bars but the V4 valve will not open, either the TC gauge is out of adjustment, or TC1 is defective.<\/p>\n
To adjust the TC gauge:<\/p>\n
1. Remove the cover on the AVC and slide it out enough to work is able to access inside of the unit. On some systems, such as the 600 Multiprobe, you can remove the tabletops and come from the top down. On other systems, such as 5000 series XPS systems, you will need to slide the AVC out of the rack a little bit.<\/p>\n
2. Refer this adjustment to qualified personnel. With a DVM, measure the voltage on pins 1 and 2 of P14. This is the connector that comes from the TC gauge control output. Pump down the intro. After you have 5 bars, you should have 9 to 10 mV DC on pins 1 and 2 of P14. If not, there is a pot on the back of the TC gauge (hockey puck) that needs to be adjusted. There is a hole on the back of the AVC that might allow you to do the adjustment from the back of the AVC with a long, thin screwdriver. Usually this does not line up and you need to remove the 3 screws at the base (under side of the AVC) that hold the TC gauge to the AVC and rotate the TC gauge up to get to the pot. Adjust the pot for 9 to 10 mV. It goes from Zero mV (air) to 10 mV (vacuum). CAUTION! <\/strong>If you have to move the TC gauge exercise extreme caution! There is a 220-volt AC terminal strip located near the TC gauge. It is recommended that the AVC be shut down (close all valves and turn off all turbo pumps first) and un-plugged before tilting the TC gauge. Touching the metal case to the exposed 220-volt AC terminal strip will cause arcing, damage to the AVC and possible electrical shock!<\/p>\n
![\"AVC-control-board\"](\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2014\/07\/AVC-control-board.png?ssl=1\")