Repair of Spectrum Analyzer HP859X display unit
Some time ago I got a HP8592L Spectrum Analyzer - obsolete because Agilent(former HP) don't repair this 10-15 years old equipment anymore but for a radio amateur it's a great instrument.
The display had a minor irritating fault - after switching on the picture appeared after 1 - 1.5 minute!
Before you disassemble the analyzer download the service manual from Agilent and follow the disassemble procedure in the manual.
Tracing an error is rather difficult without a schematic and after a mail to OMNI VISION in USA they answered very positive and applied a service manual for me - thank you!
The fault-finding was very easy - 4 measurements with an oscilloscope and the faulty component was pointed out - a coupling condenser between line generator output and basis of line output transistor Q2 - C14 a 4.7 uF/50V 85°C electrolytic capacitor was dried out.
You can with advantage replace the electrolytic with a good quality foil condenser, same capacity and voltage as the faulty one.
After repair the display picture is visible after 8 - 10 sec.
I have now repaired three HP8592L with equal faults in the display units - same condenser manufacturer!!!
HP8590 Manuals & Guides
Omni Vision LP06xx Service Manual
Updated March 30, 2009