HP 8565A?? HP 8569B?? Spectrum Analyzer: a mixed box

For next to nothing, I got hold of a HP (Agilent, now: Keysight) 8565A 8569B mixed analyzer:

8569b front panel 2

8569b panel

As you can see, the main unit, including the CRT and electronics, is a 8569B, but someone fitted a (rather incomplete) 8565A control assembly. Not a big deal, normally, but the control assembly fitted here has virtually all the common defects: missing contact wipers, and missing/defective knobs.

Another common defect (can all be fixed):
8569b wheel

A quick test – the CRT seems to be working, albeit, it is now dark after a few minutes of operation – most likely, just a dead capacitor, but the CRT itself is definitely pretty good. Also the CPU seems to work just fine.

8569b yig

The unit has a lot of RF goodies, like a 22 GHz 3-stage YIG filter, a YIG oscillator, a 22 GHz mixer, various 22 Ghz coaxial relais – but with another parts unit already at hand, this unit seems to be to precious to scrap. Well, need to think about it, always wanted to provide an electronic replacement for the aging 8565A 8569A/B control assemblies. Maybe, a good project for next winter!

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