Kipp&Zonen Brewer MkIII - Manual (Page 19)

MKIII SERVICE MANUAL 14
3. Observe Slitmask Performance.
If the mercury lamp test is normal, the spectrometer cover should be removed and another
standard lamp test done while observing the slitmask. If the standard lamp fails again while the
slitmask is operating correctly, KIPP & ZONEN should be consulted.
4. Photon Counting Circuitry
If the mercury lamp test is not normal, there is probably a failure in the photon counting circuitry
and section 4.9 of this manual should be consulted.
5. Replace Standard Lamp
Before starting disassembly, it should be confirmed that the lamp filament is open circuit by
checking with an ohmmeter across pins 1 and 5 of J111 (lamp connector). Reference fig. 10.6.2-2.
The Standard Lamp is located above the mercury lamp and is attached to a removable plate.
Remove the two screws holding the plate. Replace the bulb with a new one, taking care not to
touch it with bare fingers- use a tissue or soft cloth and clean the lamp with isopropyl alcohol after
installation. If the bulb is blackened, it should be replaced regardless whether or not it is
operational.
Replace the connector assembly and test the lamp with the B2 command. Be sure to use B0 to
turn the lamp off.
Another standard lamp test should now be tried. If there is no success, there is a possibility of
circuit failure on the Lamp Control board, or the Main Electronics board.
6. Check Main Electronics Board
Send the command to turn the Standard Lamp circuit on (B2), and measure the voltage at pin15 of
U14 on the Main Electronics Board. The voltage should be +5 volts when the lamp is off and 0 volts
when the lamp is on.
If this voltage does not change, the Main Electronics board should be replaced, or KIPP & ZONEN
consulted.
7. Check Cable
If there was an indication of a 0 to 5V voltage swing at pin 15 of U14, but still no lamp operation,
the cable that connects the Main Electronics board to the Lamp Control board should be checked.
8. Test Lamp Control Board
If the cable it is good , the Lamp Control Board should be tested for correct operation. The lamp
control for the standard lamp is very simple - Q1 pin 2 supplies power to the current regulator VR2
(both components are on the bottom edge of the Lamp Control Board). Measure Q1 pin 2, and
when the standard lamp is commanded on, it should go to 17 volts. VR2 pin 2 should be 10 volts. If
it this point does not go to 10 volts, then the current regulator circuitry is faulty and must be
repaired or the complete board must be replaced. Refer to the lamp control board schematic Fig
10.4-2.
9. Test Lamp Cable
If the voltage at VR2 does change on command, then the lamp cable should be tested for
continuity.