Document: MAN00238A
Page 20 of 28
R:\Documents\MAN Manuals\MAN00238A BRC-15-1111R-STD-J37.doc
9. CIRCUIT BOARD ADJUSTMENTS
Although each power supply is fully tested and calibrated prior to shipment, there are circuit boards
in the unit that may require adjustment at some time during the life of the power supply. These
boards are the Regulator board (9120010) and Front Panel board (9120021).
Before attempting to make any adjustments inside the power supply chassis, please be sure that the
consequences of such an adjustment are completely understood.
Do not attempt to make any adjustment unless you fully understand the function of each
potentiometer. These adjustments are preset by the manufacturer and should not be disturbed unless
you are experiencing difficulties.
Refer to Figures 4 and 5 for the exact locations of adjustment potentiometers on the circuit boards
(PWAs) listed above. Also refer to the list on the following page, which will describe the function
of each potentiometer in detail.
For a detailed description of adjustment procedures, see the Acceptance Test Procedure called out in
Section 13.
Potentiometer Function Descriptions
Front Panel PWA
9120021:
R6
Front panel voltmeter calibration.
R7
Front panel ammeter calibration.
R9
Shutdown timer one-shot period: sets length of time unit will stay in
the shutdown state after an arc or similar event.
Regulator PWA
9120010:
R1
High voltage feedback divider AC compensation: adjusts AC gain of
feedback divider.
R103
Divider current compensation: removes the loading effect (current
drain) of the internal feedback divider which would otherwise cause
an error in the current feedback signal.
R25
kV Cal: calibrates the ratio between the voltage reference and the
actual output voltage when the unit is in voltage regulation mode.
R197
mA Cal: calibrates the ratio between the current reference and the
actual output current when the unit is in current regulation mode.
R83
kV Mon Cal: calibrates the ratio between the actual output voltage
and the monitor signal, which is fed to both the User Interface J4
connector on the rear panel and to the front panel voltage meter.
R181
mA Mon Cal: calibrates the ratio between the actual output current
and the monitor signal, which is fed to both the User Interface J4
connector on the rear panel and to the front panel current meter.
