I'm trying to recucitate an HP8753C.
I replaced the YTO which was bad and was able to do the 'Source Pretune Correction Constants' adjustments procedure.
This is done with the A9 jumper in the 'ALTER' (right most) position. After adjustment the jumper is returned to the 'NORM' (let most) position.
When I do this I
do not get phase lock below 16 MHz (low band).
The High/Low Band Transition Adustment shows normal (right hand trace ~150mv highr than left).
?Do anyone have a clue as to what might be wrong?? Why would the jumper position effect the performance of the PLL?
With jumper in 'NORM' (.3 to 20MHz)
Jumper in 'ALTER' (0.3 to 20MHz)
vk2bea