Re: Yaesu FT480R
I have been mulling it over and it seems most likely that the output of Loop3, the TC9122 which is behaving correctly, cannot be reaching Loop 2 which is misbehaving.
Between the two is a division by 100. It could be here that the problem lies.
My next suggestion is to put your oscilloscope on TP07 which is the input to Loop 2 phase detector. Expect to see a signal of around 680 to 685kHz. What does it do as you tune the same range?
Does it change in amplitude - how much of it is there anyway?
Does it gradually increase in frequency in a smooth way or does it have the glitch where it increases at first and then drops back over the 5x3-5x8 range?
Crossed with you David - I cut my teeth on that ARRL section back when!! Glad you have fished out your 480R - we might be asking how yours behaves on TP07!
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