| Next Page | ||
step d above. If not, loosen the shaft pulley, mesh eapaeitor plates manually, and retighten the pulley. f. Apply a little airplane cement on the knots in the dial cords to help hold them tight. .After the cement is dry, trim the loose ends back NO CLOSER than one-quarter ineh from the knot. 4.9 RELAY MAINTENANCE Gradual accumulations of dust, lint, or oxidation may cause the contacts of relays to become high-resistance connections and degrade ssvitching functions. Relays K2 and 194 are plug-in types and can be removed for cleaning. Relay K.3 is wired in ptace and cannot be removed except by disconnecting all leads to it. If cleaning of the relay contacts is neeessary, use a relay contact burnishing tool. If such a lool is not availahle, use a piece of rough parper soaked in carbon tetrachloride. Be careful not to bend any of the contact springs. DO NOT use files, emery paper, or abrasives, as the silvered surfaees of the eontaets are very |
thin. Observe the contacts in a dental mirror, and press the armature down with thumb or finger. Check that all normally closed contacts have opened before any of the normally open contacts close. If this is not the ease, the relay may have to he replaced. 4.10 DIAL LAMP REPLACEMENT To replace the dial lamp, refer to figure 4-5 for the lamp location. When re,olacing the laml), orient the refleetor to direct the light forward to illuminate the tuning dial properly. 4.11 METER LAMP REPLACEMENT. To replace the meter laml), refer to figure 4-6.
When removing the mounting hardware from the nylon posts, extreme care is necessary to prevent breaking the post. To remove the lampholder from the meter use a small, flatblade screwdriver between the holder and the meter case. |
|