[time-nuts] HP frequency synthesizers available

Bill Hawkins bill at iaxs.net
Thu Apr 9 19:55:39 EDT 2015

The time has come to prepare to move to smaller quarters, so the time
lab must go.

I have three HP 3335A 200 Hz to 80 MHz programmable (HPIB) synthesizers.
These use analog VCOs controlled by digital logic to generate nearly
pure sine waves. The specs are available on the web.

I got the first one from the electronic Bay of Chances in 2003. It
didn't work, so I got another. It didn't work, either. So I bought one
from Nebraska Test Equipment that did work, but it had Western Electric
telco connectors and 75 ohm impedance, among others. None were really
useable. I thought it would be diverting to cure that when I retired,
but other things happened. Now I have to sell them, so I dedicated 2
weeks to the task.

The Nebraska unit now has a WECO to BNC adaptor. A 25 ohm resistor in
the telecom option box can be removed to get 50 ohms, which is the
impedance of the output amplifier. Timenuts price is $495 OBO.

The two non-working units yielded one good one after a repair to the
power supply. I can verify frequency accuracy with a Racal model 1992
counter, but not amplitude, which is approximately correct. I can't test
the HPIB interface. This unit has the high stability reference
oscillator option. Price is $395 before it goes to eBay.

The third parts unit has a working 10 MHz oscillator and seven of the
eight RF assemblies are known good. The attenuator clicks but has no
output. The front panel control card has problems, such as lighting all
of the decimal points. Assembly A6 has a problem with the level control
that keeps the output low. The level controller could easily be
bypassed. The power supply has an open pass transistor for -5.2 volts.
Oh, and the HPIB board has been marked BAD by someone else. How about
$150 for it? Also have the operating and service manual. I really enjoy
working on equipment built before surface mount parts, more than reading
stories in books (started on R390 class receivers).

The units weigh 45 pounds each. Shipping from 55438.

There is also an HP 3320B in working condition, 10 Hz to 13 MHz full
scale ranges.

And if you wanted 200 watts of precision frequency power, say for 60
cycle synchronous motor clocks, there are two Altec-Lansing 1590
distribution amplifiers designed to work with 24 VDC battery backup.
Could also be used as a 200 watt UPS with a suitable frequency source,
such as the HP 3320B or a Raspberry Pi.

Please write for details and pictures to bill at iaxs.net.

Bill Hawkins

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