History: HP 8566A Repairs

Source of version: 1 (current)

Got 2 of these units recently. Some notes about what was broken with each: !!!Unit 1 #REF UNLOCK: Solved by providing the INT->EXT jumper cable for the frequency reference in the back of the unit. #0-2.5GHz range would show signal 50dB down from actual. This was caused by a broken 1st converter which would drop 50dB in its output level whenever it got warm. Got a replacement 1st converter on the way for $20+shipping. #Display is a bit dim/unfocused: Will need to do IF Section fix for this. #Should pro-actively replace battery and provide handles. !!!Unit 2 #All LEDs light up and does not boot: Identified as a problem in the RF Section since IF Section worked with a different RF Section. Further identified the problem as the CPU card (A15) since replacing it with a working A15 from another RF Section made this unit boot up and all LEDs turned off. On the A15 card itself the problem was shredded air filter contamination. It was sitting between the CPU die carrier and the PCB, where the ring wires make the connection. Cleaned up the PCB contacts for the CPU, the CPU contacts and the ring wires, re-seated, tightened, and the unit boots up! Prior to this also needlessly replaced all capacitors on CPU board. They measured their capacitance just fine when out of circuit, but I don't have an ESR meter to see if they've degraded in that way. So replaced them anyways. #Crushed face on RF Section: Will need to superglue/jb-weld this back into normal shape. The instrument frame behind the face is also bent and will need adjustment. No damage to the RF components or connectors thankfully! #A few buttons don't work on RF Section face: I think these will just need to be pressed a lot. Several buttons on the IF Section didn't wanna work either until they were exercised. Common with switches that sit idle for a long time. #Rotary encoder does not work on the RF Section face: This one was likely damaged in the face crushing event. Will have to disassemble and see if it's fixable, or order up an equivalent encoder to replace it. #Battery is exploded/carrier terminals corroded off: I'll have to come up with some new way of mounting a proper battery to this. #IF Section is 40(?)dB down for narrow bandwidths: Will have to check out filters in IF Section. #Should provide handles.

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