[time-nuts] Finally acquired a 5370B

John Miles jmiles at pop.net
Wed Jun 11 22:00:58 EDT 2008

There's a lot about 5370s in the archive.  Common problems seem to be
intermittent sockets for the ROM chips, and (in my own experience) dirty
polarity/impedance/attenuator switches.  The manual has a good self-check
procedure for the internal circuitry, but you need to be careful to ensure
that the front-panel switches do what they're supposed to do without
degrading the measurements you're trying to make.

Also make sure the trigger level-control DACs are aligned properly.  5370s
purchased in the surplus market are rarely spot-on in this regard.  It's
important if you are going to be making two-channel measurements, because
the relative-phase accuracy is only as good as the trigger stability and

The voltage limits in the manual may be different from what your particular
counter uses (e.g., 2.56V in the manual versus 2.048V or 1.920V in real
life) but it should be possible to adjust them symmetrically, and establish
stable zero levels with the controls in their PRESET positions.   (At least
one edition of the manual has a typo in the calibration instructions for
that section.)

They're nice counters, and that does sound like a great price!

-- john, KE5FX

> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On
> Behalf Of Jim Palfreyman
> Sent: Wednesday, June 11, 2008 6:44 PM
> To: time-nuts at febo.com
> Subject: [time-nuts] Finally acquired a 5370B
> Hi all,
> Well getting a second hand 5370B will be no big deal for those of
> you in the
> US, but in Australia getting one of these units is very expensive due to
> rare local availability and cost of postage from the US. I was recently
> quoted US$350 - more than the unit itself cost!
> However after patiently waiting two years I recently won an auction at a
> decent price and the postage was a very "reasonable" US$170.
> Now whilst waiting for it to arrive I've downloaded the full
> manual and read
> up as much as I can without having the ability to play with the unit yet.
> However, what I'm after is any hints, tricks or gotchas I need to
> watch out
> for. The unit looks like it will be in good order (ebay id
> 300229475698) but
> any guidance or advice would be much appreciated.
> Regards,
> Jim

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