Chapter Three: Overview
Inside the Type 146 Unit
57
Configuring the Hot Cathode Board for a Low Power Hot Cathode
The Hot Cathode board can be configured for a low power hot cathode (the default is for a high
power gauge). MKS will configure the board at the factory, if specified on the order. If you did
not request the low power configuration, but wish to use the board with a low power hot cathode,
follow these instructions.
Caution
1. Be sure to have the correct setting for your hot cathode. Damage
may occur to a low power hot cathode gauge if you operate it with
the high power gauge configuration because excessive power
would be applied to the grid during degas.
2. If two Hot Cathode (HC) boards are installed in one unit, the HC
boards MUST be set to low power configuration. Otherwise, the
146 unit may exceed its temperature rating.
Warning
The 146 unit has lethal voltages inside. To avoid the danger
of electrical shock, disconnect the power line
before opening
the unit.
1. Be sure the power cord is disconnected.
2. Disconnect all cables from the 146 unit.
3. Remove the four (4) Phillips screws on the outside corners of the rear panel and the
seven (7) screws from the top cover.
4. Remove the top cover by firmly pulling it towards the back of the unit. Note the
orientation of the cover since the center hole is slightly off center to accommodate a
connector if a board is positioned in slot 5.
5. Carefully turn the unit over so that it is bottom-side up and remove the seven (7) screws.
6. Remove the bottom cover by firmly pulling it towards the back of the unit. Note the
orientation of the cover since the center hole is slightly off center to accommodate a
connector if a board is positioned in slot 5.
7. Remove the Phillips screw that is securing the Hot Cathode board to the bottom of the
146 unit.
8. Carefully turn the unit right-side up.
9. Unscrew the two small screws holding the slot cover on the Hot Cathode board.
10 Carefully but firmly pull the Hot Cathode board out of the unit.
11. Remove one of the shorting jumpers which is currently stored on JP4.
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com