KB BM20 tuning capacitor - UK Vintage Radio Repair and Restoration Discussion Forum

newlite4 · 6th May 2005, 11:50 am

I have been restoring one of these this week for an antique dealer. I was surprised at just how scratchy the tuning capacitor was. The unit was protected by a celluloid shield through which there was no visible sign of contamination. I removed the shield and noticed that it had shrunk and that the vanes of the tuning capacitor had been rubbing against its inner surface. On subsequent test without the shield, scratchless tuning was restored. I can only imagine that the celluloid shield had acted as a conductive path for the vanes. Definitely one to watch out for.
Neil

Richard · 6th May 2005, 9:52 pm

Hi Neil

If you are working on this for an antique dealer, is it for sale??

Richard.

newlite4 · 9th May 2005, 9:25 am

Hello Richard, I think that he plans to keep it for a bit. I did a DAC90a for him last week and he plans to hold on to that, at least until something rarer turns up

.
Neil

Richard · 12th May 2005, 10:16 pm

Hi Neil

Ok, thanks for that.

Richard

6th May 2005, 11:50 am	#1
newlite4 Octode Join Date: Nov 2003 Location: Bath, Somerset, UK. Posts: 1,805	KB BM20 tuning capacitor I have been restoring one of these this week for an antique dealer. I was surprised at just how scratchy the tuning capacitor was. The unit was protected by a celluloid shield through which there was no visible sign of contamination. I removed the shield and noticed that it had shrunk and that the vanes of the tuning capacitor had been rubbing against its inner surface. On subsequent test without the shield, scratchless tuning was restored. I can only imagine that the celluloid shield had acted as a conductive path for the vanes. Definitely one to watch out for. Neil

6th May 2005, 9:52 pm	#2
Richard Heptode Join Date: Feb 2003 Location: Garnant, near Ammanford, South Wales, UK. Posts: 657	Re: KB BM20 tuning capacitor Hi Neil If you are working on this for an antique dealer, is it for sale?? Richard. __________________ BVWS member.

9th May 2005, 9:25 am	#3
newlite4 Octode Join Date: Nov 2003 Location: Bath, Somerset, UK. Posts: 1,805	Re: KB BM20 tuning capacitor Hello Richard, I think that he plans to keep it for a bit. I did a DAC90a for him last week and he plans to hold on to that, at least until something rarer turns up . Neil

12th May 2005, 10:16 pm	#4
Richard Heptode Join Date: Feb 2003 Location: Garnant, near Ammanford, South Wales, UK. Posts: 657	Re: KB BM20 tuning capacitor Hi Neil Ok, thanks for that. Richard __________________ BVWS member.