Wavetek 145 Instruction Manual page 40

4. Invert the unit (bottom side up).
5. Remove the four bottom cover screws and cover.
6. Remove all front panel knobs except the fre-
quency dial knob.
7. Position the unit upside down (bottom of unit)
with the front panel away from you.
8. Remove the three screws holding the heat sinks
of the trigger/pulse board to the rear panel.
9. Remove the two screws attaching the front
panel to the right side panel (labeled "R.H." in
drawing 0102-00-0621 ).
10. Remove the two screws securing the rear panel
to the left side panel.
11. Remove the two screws securing the generator
board to the left side panel mounting brackets.
12. Unsolder the large No. 18 (black) ground on the
function output BNC.
13. To remove the generator board, disconnect the
following wires from the generator board loca-
tions:
E28 (coax) and E29 (shield), function output;
E26 {yellow) and E27 (white-black), Ext DC;
E6 (green) and E7 (white-black), GCV;
E1 (brown) and E2 (white-black), VCG;
E4 (red), E5 (brown) and E3 (orange), dial pot;
E23 (pulse select);
E21 (pulse disable);
E24 (pulse coax);
E25 (pulse coax shield).
Disconnect the Molex connector.
14. Slide the rear panel to the right and backwards.
Notice that the wires for the power supply are
connected to the rear panel.
15. Remove the two screws attaching the generator
board to the mounting brackets on the right side
panel.
16. Remove the four screws securing the generator
and trigger/pulse boards together.
17. Remove the main board back and upwards.
6-4
18. For troubleshooting the generator and trigger/
pulse boards, turn the instrument around with
the front panel facing you (keep the unit in-
verted). Place the generator board (component
side up) on a working surface with the board on
the right side of the unit. Ensure the generator
board is lying on a nonconductive surface and
not making physical contact with the rest of the
unit. Jumper E3 and E4 simulate the top of dial
frequency voltage. Pull J1 (Molex connector)
from the instrument and plug into position on the
generator board. Add the following jumpers
between the generator and trigger/pulse board:
Trigger/Pulse
E34 (pulse select)
E39 (pulse disable)
E37 (pulse coax, center)
E38 (pulse coax, shield)
Generator
E23
E21
E24
E25
It may be necessary to replace some of the
knobs to set up various test conditions.
At this point, the entire instrument is accessible
for troubleshooting. To reassemble, perform
steps 6 through 19, paragraph 6.5.2.
19. To remove the trigger/pulse board, remove the
two screws connecting the power switch to the
trigger/pulse board.
20. Unsolder the following wires from the trig-
ger/pulse board:
E1 (blue);
E2 (white-blue);
E3 (blue);
E4 (red);
E5 (white-red);
E6 (red);
E? (green);
E8 (green);
E9 (blue);
E1 O (red);
E11 (violet);
E12 (white);
E13 (white);
E14 (white);
E15 (gray);
E16 (orange);
E17 (red);
E18 (white-black);
E19 (yellow);