Richard Shireby, G0OJF, from TSG Communications, Lincolnshire, UK, discusses & demonstrates the alignment procedure of the Fidelity CB1000FM (UK) CB radio from 1981. This particular set is a scrap set from stock, being repaired & aligned for the purpose of this demonstration. These sets, made by Great of Taiwan, use an unusual synthesiser chip. The Fidelity CB1000 is the only radio that uses the GT848 chassis. Other badged Great chassis models such as the Lake 850, use the GT858 chassis which is the same but with no Ext speaker socket, and other models such as the Lake 950 use the GT868 chassis, which simply has more knobs on the radio & PA facility.
After getting the radio to initially work, I show you the VCO adjustment. I was unable to set up the TX VCO with a meter, so show a logic probe in use instead. However, on RX couldn't get a reading on the logic probe, but could on the meter! The service manual says to set the VCO with an oscilloscope, so I move the radio from our usual test bench no.2, to test bench no.3 to demonstrate the oscilloscope method. However, seeing as only test bench 2 is video equipped, I have to show you procedures with a hand held camcorder instead....don't get sea sick!
I bought this scrapper from a local radio ham rally for £2