HMV 1124 - Rogue Osc. Trimmers - UK Vintage Radio Repair and Restoration Discussion Forum

MikeBeith · 15th Jul 2007, 4:29 pm

Managed to restring the dial cord after forum advice and cleaning the two rails that carry the pointer carriages. Power on through a variac, no smoke, no bangs but no rf on any band (MW,LW,SW1,SW2). AF stages fine, checked at gram input.

Further investigation revealed no oscillator function on any band. Eventually found all four oscillator trimmers capacitors short circuit. One maybe, but all four

They are concentric brass, similar to the old aluminium beehive type but bolt fixing and look more rugged. Replaced them with modern plastic film trimmers and lo (sorry about the pun) - it worked. I have examined one of the faulty trimmers and can find no trace of corrosion between the concentric tubes but the clearance is minimal - a few 'thou' at most. This radio lived in a seaside enviroment so maybe salt air and and moisture problems?

Any one else found this problem?

Mike

15th Jul 2007, 4:29 pm	#1
MikeBeith Retired Dormant Member Join Date: Jun 2007 Location: Fenwick, Kilmarnock - Ayrshire Posts: 13	HMV 1124 - Rogue Osc. Trimmers Managed to restring the dial cord after forum advice and cleaning the two rails that carry the pointer carriages. Power on through a variac, no smoke, no bangs but no rf on any band (MW,LW,SW1,SW2). AF stages fine, checked at gram input. Further investigation revealed no oscillator function on any band. Eventually found all four oscillator trimmers capacitors short circuit. One maybe, but all four They are concentric brass, similar to the old aluminium beehive type but bolt fixing and look more rugged. Replaced them with modern plastic film trimmers and lo (sorry about the pun) - it worked. I have examined one of the faulty trimmers and can find no trace of corrosion between the concentric tubes but the clearance is minimal - a few 'thou' at most. This radio lived in a seaside enviroment so maybe salt air and and moisture problems? Any one else found this problem? Mike