HP 5342A Microwave Frequency Counter

© Brooke Clarke 2010

My prior frequency counters have a upper frequency limit below the microwave range and for some things it would be handy to have a counter with a higher upper frequency limit (18 GHz or 24 GHz).

Upon arrival the counter powered up and could count its own 10 Mhz Ref output, so seemed OK.  When it's front panel switch is turned to standby the oven stays heated.  After sitting overnight with the oven on, when the power switch was turned on the fuse (2A 125V) blew!  The fuse has been removed in the photo above.  Next to get the Operation & Service manual from Agilent (05342-90057 24.5 MB).

The 125 VAC fuse should be a 0.75 A and the 230 VAC fuse should be 0.375 A, so a prior owner has put in a much larger fuse (2A SB), indicating there's a progressive problem like leaking caps.

s/n: 2636A11350
Options:

Option	Description	p/n	Installed
001	Hi Stab Time Base	10544A	Yes
002	Amplitude Meas	05342-60200	?
003	Extended Dynamic Range	05342-60201	?
004	Digital-to-Analog Converter	05342-60202	?
005	24 GHz (not with opt 2 or 3) in s/n 1936A and up		?
006	Limiter		?
011	HP-IB	05342-60019 05342-60029	Yes

? is shown under installed because the newer model may have these as stock items?
001 High Stability Time Base HP 10544A
011 HP-IB