Test Selectable Parts - Tektronix VITS 200 Instruction Manual

Maintenance

Test Selectable Parts

7–8
4. Remove the oven from the Inserter board by carefully pulling the oven off
the seven square pins that attach it to the Inserter board.
5. Remove the screw attaching the metal cover to the oven.
6. Remove the screw attaching the circuit board to the oven and pull the
oscillator out of the oven.
Controller Board Removal
1. Disconnect the REMOTE and RS-232 ribbon cables.
2. Remove the retaining nuts on the six BNC connectors that extend through
the rear panel.
3. Disconnect the three ribbon cables and four coax cables which connect the
Controller and Inserter boards.
4. Disconnect the three front-panel cable assemblies from the Controller board.
5. Remove the nine mounting screws.
6. Carefully angle the front of the circuit board up and slide it forward until the
BNC connectors clear the rear panel, and then lift the board away from the
instrument.
Test selectable capacitors A1C31, A3C66, A3C67, A3C68, and A3C69 are
normally not needed. These capacitors are only installed when the associated
integrated circuit pin 18 cannot be adjusted for a clean 6V "1V during the
Genlock Adjustment procedure (see Table ). When needed, these capacitors are
usually 130 pF, but may be selected from the range of 0 pF to 470 pF.
Table 7–3: Test Selectable Parts
Pin 18 of
A1U44
A3U3
A3U4
A3U9
A3U11
Add Capacitor In Parallel With
A1C31
A3C66
A3C67
A3C69
A3C68
A3C11
A3C7
A3C8
A3C31
A3C32
VITS 200