Greetings all...
New guy on the forum. I read the forum for a long time because the useful hints for repairing test equipment.
I got a HP 8660D Synthesizer System as “for parts or repair”.
The system has some labels “Polar use only” and “modified for Polar”.
The system powers up and I can see an output signal at the spectrum analyzer. It’s permanently sweeping or jittering, independent of the selected modulation or when the modulation is switched off.
I thinks it’s a fault and I have to search for a phase locked loop which doesn’t lock.
Other problem:
The Sweep Rate button does not change the speed and the indicating light for the sweep rate does not show. But at power up, all the lights are flashing. So the Led’s are o.k.
The push button is also functional, because pressing “SHIFT” and “Sweep Rate” provides the Reset functionality.
So I open the “Digital Control Unit” module. The EPROM at the processor board doesn’t looks like an official HP Chip.
Is that the modification marked by the labels ? (“POLAR”)
Does anybody have a memory dump of the EPROM at the A1A3 board ?
Searching at the web without success…