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Repairing Zenith 455 KHz IF transformer capacitors with silver mica disease
Zenith R615 radio, chassis 6J05. This radio had the classic symptoms of silver mica disease. Intermittent static crashes, Changing sensitivity, beginning 10-15 minutes after turn on. |
IF can AM 455 KHz. |
IF can with shield removed. |
Typical parts layout of IF can. This is 1st IF can, contains two capacitors. |
capacitor plate with contacts. This is the 2nd IF can, It contains three capacitors. |
Capacitor prior to cleaning. Note the silver oxide migration bridging the clear areas in the center and outside. Capacitor silver oxidation removed with a pencil eraser, then cleaned with Q-tips dipped in Isopropyl alcohol. The capacitor contacts were cleaned with alcohol also. |
Capacitor after cleaning, partially reassembled. |
Schematic of Second IF can 95-1102. |
Schematic of First IF can 95-1101. |