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Jon_G4MDC · 21st Jun 2019, 2:42 pm

I was just looking at it some more. I have found the tuning line which the PLL uses to adjust the frequency of the local oscillator and all the signal frequency tuned circuits.

If you have a Volt meter it could be interesting to see what that line is doing. At the low frequency end of the band it should have relatively low Voltage increasing the higher in frequency you tune. If that line is stuck with Voltage high or low not moving with tuning then it is fairly sure the PLL is out of lock.

Do you have a Voltmeter of any kind?

21st Jun 2019, 2:42 pm	#13
Jon_G4MDC Nonode Join Date: Nov 2015 Location: Welwyn Garden City, Hertfordshire, UK. Posts: 2,015	Re: Signal Communications Corp R535 Receiver I was just looking at it some more. I have found the tuning line which the PLL uses to adjust the frequency of the local oscillator and all the signal frequency tuned circuits. If you have a Volt meter it could be interesting to see what that line is doing. At the low frequency end of the band it should have relatively low Voltage increasing the higher in frequency you tune. If that line is stuck with Voltage high or low not moving with tuning then it is fairly sure the PLL is out of lock. Do you have a Voltmeter of any kind?