Model 618B Sect. IV Page 23
6) Remove the three screws holding the poten-
tiometer to the mounting ring and withdraw po-
tentiometer. Do not loosen screws holding mount-
ing ring to casting.
FROM COUPLER
7) Remove rear cover and place shaft of new po-
tentiometer in the coupler. Do not tighten the set
screws.
8) Position the new potentiometer with the termi-
// CASTING nals near the top and replace the three mounting
@ LOOSEN THESE TI0 SCREWS ONLY
LD.I.,,. screws and spacers. Position the potentiometer
so that shaft does not bind in coupler during any
portion of coupler rotation. Tighten mounting
Figure 4-14. Detail showing Reflector
screws.
Potentiometer Removal
9) With an ohmmeter connected between the blue
and white leads on the potentiometer, turn the
the side gussets. Pull panel assembly away from frequency dial control to the high frequency stop.
the chassis to give access to the reflector poten- The resistance measured across these terminals
tiometer. should be between 50 and 100 ohms.
3, Remove leads from On potentiometer*
10) Replace rear potentiometer cover and re-
connect leads.
4) Remove Tru-Arc ring and potentiometer rear
cover.
11) Tighten set screws in the coupler.
5) Loosen only the two set screws holding poten-
tiometer shaft in the coupler, Donot loosen screws 12) Reset repeller voltage adjustments as de-
holding coupler to the front panel shaft. scribed in paragraph 4-12. |
ACEC
