[time-nuts] HP-3336A Manual

Jeroen Bastemeijer J.Bastemeijer at TUDelft.nl
Tue Jul 17 05:55:24 EDT 2007

Dear Tom, Greg, other Time-nuts,

I was triggered by the story of Greg about the high precision 
attenuators. Lately I bought a bunch of Agilent high precision 
attenuators. These have Agilent/HP part numbers 3332x-xxxxx  (x denotes 
various numbers). These units were bought cheap, so ...... defective. 
I'm still working on them, but I can manage to end up with 2 or 3 
working attenuators.

If you are going to work on them, all you need is a small hex-key. But 
beware: These units are made in a very inventive professional way. Don't 
get tempted to remove the solenoids from the "main-frame" without 
detaching the bottom-side (were the RF-connectors are). First remove the 
bottom-side and by carefully bending remove the plungers from the 
RF-tongues. By not doing so, the tongues can be damaged. A damaged 
tongue is impossible to repair, as it is very thin copper(?) which is 
glued in place on an insulator.

Tip: Check the small O-rings which are used as dampers for the plungers. 
You can see them at the place were the plungers are connected to the 
moveable parts of the solenoids. There should be two at each plunger, 
one for the push, the other one for the pull action.

Good luck!

73 Jeroen PE1RGE

Greg Burnett wrote:

>); SAEximRunCond expanded to false
>Errors-To: time-nuts-bounces+j.bastemeijer=tudelft.nl+j.bastemeijer=tudelft.nl at febo.com
>I was last involved with a 3336A about 12 years ago, so I hope I can still
>remember the correct situation (but no guarantee).
>As I remember it, there are some relays in that aluminum box between the
>circuit board and the front panel 75, 135 and 600 ohm outputs. If you have
>the older, tall, yellow plastic relays in there, then those relays might be
>your problem -- they were not reliable over time. But if you have the newer,
>black low-profile Omron relays, then you've got good relays (that are far
>less likely to fail).
>Given your symptom, I'd guess you have the older, tall, yellow plastic
>relays. If I remember correctly, that version relay clips to the PCB and its
>gold leaf contacts actually touch pads on the PCB -- so the PCB itself
>becomes part of the relay action. The newer, black Omron relays are potted,
>completely self-contained, and are soldered into a re-designed board.
>BTW, if your unit has the option 005 precision attenuator, then the
>precision attenuator is an aluminum cast base, with solenoids on top (and a
>removeable cover for access to the solenoids) and a factory-only-repairable
>main channel milled-into the aluminum base, with the attenuator pads in the
>form of laser-etched substrate pads that fit into the channel. ...The
>solenoids push various gold-plated leaf contacts against the small contact
>pads on the substrate pads.
>----- Original Message ----- 
>From: "Tom Clifton" <kc0vsj at yahoo.com>
>To: <time-nuts at febo.com>
>Sent: Monday, July 16, 2007 1:16 PM
>Subject: [time-nuts] HP-3336A Manual
>I perused the pdf manual and came up more confused
>than when I started...
>My problem seems to be in the Option 005 high
>precision attenuator (as I  can best tell). There is
>an aluminum box between the circuit board and the
>front panel 75 ohm, 135 ohm and 600 ohm outputs.  That
>mysterious 'box' seems to be open.   I'm not sure if
>it is just an impedence matching assembly, or if it
>includes the option 005.
>As the front panel level control is changed, the raw
>50 ohm board output measures between +5 and -5 dbm and
>every time the display crosses a -3dbm threshold (-3,
>-13, -23 etc) you hear a relay click and the raw
>output jumps back up 10db.
>Hope that clarifies more than confuses...
>time-nuts mailing list -- time-nuts at febo.com
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>and follow the instructions there.

Ing. Jeroen Bastemeijer

Delft University of Technology
Department of Electrical Engineering
Electronic Instrumentation Laboratory
Mekelweg 4, Room 13.090
2628 CD Delft
The Netherlands

Phone: +
Fax: +
E-mail: J.Bastemeijer at TUDelft.nl
GPS: Lat N52.00002 Lon E4.37157 Alt 46.2m

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