Murphy U472 NO FM ! - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

benjamin77 · 7th Jul 2009, 3:59 pm

Success.....Now working on all bands. Traced the problem to a cap on the screen of the 10C14. It was one of them horrible litle resistor look a likes rated at 3nf ! Many thanks to all

Hunts smoothing bomb · 8th Jul 2009, 1:09 pm

Good job Ben! well done, now I would change cap 39 on the screen of the 10F18 if you haven't already as it will break down sooner or later and cause the same symptom. (just out of interest when it happened to me I found that those little caps actually went open circuit which caused instability at I.F.

Cheers

benjamin77 · 8th Jul 2009, 3:58 pm

HI Lee
Yes your right , when I tested it I to found it was open circuit...! I have also changed the other one as you suggested. It would seem that none of them can be trusted...!

7th Jul 2009, 3:59 pm	#21
benjamin77 Retired Dormant Member Join Date: May 2009 Location: High Wycombe, Buckinghamshire, UK. Posts: 326	Re: Murphy U472 NO FM ! Success.....Now working on all bands. Traced the problem to a cap on the screen of the 10C14. It was one of them horrible litle resistor look a likes rated at 3nf ! Many thanks to all

8th Jul 2009, 1:09 pm	#22
Hunts smoothing bomb Octode Join Date: Oct 2005 Location: Wimborne, Dorset, UK. Posts: 1,407	Re: Murphy U472 NO FM ! Good job Ben! well done, now I would change cap 39 on the screen of the 10F18 if you haven't already as it will break down sooner or later and cause the same symptom. (just out of interest when it happened to me I found that those little caps actually went open circuit which caused instability at I.F. Cheers __________________ Lee

8th Jul 2009, 3:58 pm	#23
benjamin77 Retired Dormant Member Join Date: May 2009 Location: High Wycombe, Buckinghamshire, UK. Posts: 326	Re: Murphy U472 NO FM ! HI Lee Yes your right , when I tested it I to found it was open circuit...! I have also changed the other one as you suggested. It would seem that none of them can be trusted...!