UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - KB FB10

boxdoctor · 9th Jan 2019, 10:08 pm

Hi Mike,
Thanks for the quick and helpful reply.
I injected the sig generator (Gould-Advance SG200, accurate) into the mixer grid circuit via a 50pf mica cap. A quick sweep across the likely frequency band showed a sharp peaked response at 465Khz, with a bandwidth (estimated) of about ± 6 Khz or so. There was no other response around that frequency. I specifically checked on the low frequency side, as that was where I was expecting the I.F. amplifier to be tuned to.
Looks like the previous "repairer" decided that the I.F.s were "off", and needed re-aligning.

"465 must be right, they're all 465 ain't they, innit?"

I am reluctant to do any adjustment due to the woeful screw thread arrangement with the cores referred to in my previous post. Tony.

9th Jan 2019, 10:08 pm	#3
boxdoctor Rest in Peace Join Date: Sep 2010 Location: Ripley, Derbyshire, UK. Posts: 785	Re: KB FB10 - I.F. frequency query. Hi Mike, Thanks for the quick and helpful reply. I injected the sig generator (Gould-Advance SG200, accurate) into the mixer grid circuit via a 50pf mica cap. A quick sweep across the likely frequency band showed a sharp peaked response at 465Khz, with a bandwidth (estimated) of about ± 6 Khz or so. There was no other response around that frequency. I specifically checked on the low frequency side, as that was where I was expecting the I.F. amplifier to be tuned to. Looks like the previous "repairer" decided that the I.F.s were "off", and needed re-aligning. "465 must be right, they're all 465 ain't they, innit?" I am reluctant to do any adjustment due to the woeful screw thread arrangement with the cores referred to in my previous post. Tony.