UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post

Tractorfan · 18th Dec 2010, 7:52 pm

Hi Guys,
I recently posted my KB radiogram in the success stories section as it works a lot better than it used to and I'm really pleased with it. I replaced the ECC81 in the FM front end with an ECC85 after rewiring the heater connections. I realigned the set by ear as I've no test gear apart from a multimeter. It now pulls in stations very well even on its internal aerial which is quite an achievement in a house with very thick walls.
The only snag now is that the sound has a "fuzzy" distortion and no amount of tweaking will improve it. It's as if it is ever so slightly off tune. If the local oscillator was on the "wrong" side on the received frequency, would that cause it? If so, then I should be able screw the brass slug through its coil to shift its frequency to the "right" side. Yes?
Am I barking up the right tree? Or just barking?

Cheers & Merry Christmas, Pete

18th Dec 2010, 7:52 pm	#1
Tractorfan Dekatron Join Date: Mar 2008 Location: St. Frajou, l'Isle en Dodon, Haute Garonne, France.(Previously: Ellesmere Port, Cheshire, UK.) Posts: 3,184	"Fuzzy" FM Hi Guys, I recently posted my KB radiogram in the success stories section as it works a lot better than it used to and I'm really pleased with it. I replaced the ECC81 in the FM front end with an ECC85 after rewiring the heater connections. I realigned the set by ear as I've no test gear apart from a multimeter. It now pulls in stations very well even on its internal aerial which is quite an achievement in a house with very thick walls. The only snag now is that the sound has a "fuzzy" distortion and no amount of tweaking will improve it. It's as if it is ever so slightly off tune. If the local oscillator was on the "wrong" side on the received frequency, would that cause it? If so, then I should be able screw the brass slug through its coil to shift its frequency to the "right" side. Yes? Am I barking up the right tree? Or just barking? Cheers & Merry Christmas, Pete __________________ "Hello?, Yes, I'm on the train, I might lose the signal soon as we're just going into a tunn..."