[R-390] Signal Generators (was: Deoxit)

[Don Reaves W5OR]

I second the HP-606 boatanchor nomination, especially the HP-606B model.
It has a high level secondary output, independent of the calibrated
output, that is useful for connecting to a frequency counter.  As Cecil
says, they are built like tanks, and the only trouble I've had with mine
is that the grease in the band turret got old and gummy and finally
prohibited easy band changing.  I used a degreaser to soak out the old
grease over a period of a week and then applied new lubrication.  Works
like new.  Be careful buying signal generators - they often have the
attenuator fouled up and you will need a functioning calibrated output
for tweaking your R-390.

The URM-25 is the genny called out in the manuals.  They are much
smaller and compact and a bit harder to work on should you need to
repair one.  But it is the classic choice.   

I've never owned an 8640B but you can trust Walter's recommendation.
8640s are on the workbenches of Chuck Ripple and Rick Mish.  Be sure you
get one that does not have the attenuator burned out.

A friend who is tuned into the used test equipment market says prices
for high quality older test equipment are just absolutely sinking.  So
it's a great time to upgrade your workbench.  At a recent Texas hamfest
test equipment was nearly being given away.  For example, I picked up an
HP-3586B Selective Voltmeter, an HP-3330B Synthesizer, and several
Watkins Johnson counters.  The pile was less than $200.       
Manuals for this stuff will probably cost more than the equipment.

DeOxit.  
For a while, you could find DeOxit on their web site in ten dollar
sample kits, which was enough to cure several R-390s of oxidized
contacts.  They furnished an assortment of their products in 2cc plastic
tubes in the kit.  Part number 2C-SAMP.  Included CaiLube (for pots) and
R-5 (good for flashlight batteries).  I just checked, they still have
web specials, called survival kits (hehe).  K2C is the closest match to
what they used to offer.  Still ten bucks.  www.caig.com

Don Reaves