Cleaning Switch contacts and machanisms on HP239a Oscillator


Richard Merifield
 

Hi All,

I picked up a well loved HP239a oscillator in need of some care and cleaning. Still produces a super clean sine wave. Missing knobs etc makes the restoratin a chllenge.

The rotary switch contacts look rather fragile and I was wondering whether anyone had any experience on the best way to clean these and which product to use ? I have attached a photo, there is some oxidation visible. I am reluctant to pull the whole thing apart which makes access dificult.

Regards

Richard


 

Hi Richard,

 

I think this message was meant for the hpagilentkeysight group.

We’re just some simple computer nerds.. 😉

 

-Rik

 

Van: VintHPcom@groups.io <VintHPcom@groups.io> Namens Richard Merifield
Verzonden: dinsdag 12 oktober 2021 11:56
Aan: VintHPcom@groups.io
Onderwerp: [VintHPcom] Cleaning Switch contacts and machanisms on HP239a Oscillator

 

Hi All,

I picked up a well loved HP239a oscillator in need of some care and cleaning. Still produces a super clean sine wave. Missing knobs etc makes the restoratin a chllenge.

The rotary switch contacts look rather fragile and I was wondering whether anyone had any experience on the best way to clean these and which product to use ? I have attached a photo, there is some oxidation visible. I am reluctant to pull the whole thing apart which makes access dificult.

Regards

Richard


Paul Birkel
 

Richard:  FYI, there is an *extremely* active groups.io forum packed with folks having all sorts of problems and related experience that can be brought to bear on your challenge :->.  See:  https://groups.io/g/HP-Agilent-Keysight-equipment

 

Some folks “here” are also “there” as well.


Richard Merifield
 

Thanks Paul. Had not seen that group. I will join and post over there.


 

On 10/12/21 5:55 AM, Richard Merifield wrote:
I picked up a well loved HP239a oscillator in need of some care and cleaning. Still produces a super clean sine wave. Missing knobs etc makes the restoratin a chllenge.
The rotary switch contacts look rather fragile and I was wondering whether anyone had any experience on the best way to clean these and which product to use ? I have attached a photo, there is some oxidation visible. I am reluctant to pull the whole thing apart which makes access dificult.
Others have pointed you to the hp-agilent-keysight-equipment mailing list; I saw your subscription go through.

What you want for this is DeOxit D5. Apply it sparingly to the contacts and work the switches back and forth. Repeat this a couple of times. The carrier will evaporate leaving a protective layer behind; leave that there.

Good luck.

-Dave

--
Dave McGuire, AK4HZ
New Kensington, PA


 

I collect HP test equipment too… I use DeoxIt to clean such rotary switches. Good luck in your restoration!
Marc


Steve Leibson
 

I too have used Deoxit successfully. I've used it since 1986, when I wrote an article about contact cleaners for EDN. Back then, it was called Cramolin and came in blue and red. Still have some of that. These days, I use Deoxit Gold. Just type "Deoxit" into Amazon to see what's available.

--Steve



On 10/12/2021 11:13 PM, CuriousMarc wrote:
I collect HP test equipment too… I use DeoxIt to clean such rotary switches. Good luck in your restoration!
Marc
-- 
Steve Leibson

Phone (Cell): 408-910-5992
Phone (Home): 408-292-4930


Please feel free to link to me on LinkedIn


History site: www.hp9825.com



Jack Rubin
 

Holy Poop Batman, what a name to forget!
Thanks, Steve, for the reminder.
--
Jack
www.computerarium.org


gtracyca <gtracy@...>
 

At the risk of extending this thread too long.....
I used to repair 239's for HP back in the 70's.
Camolin was my go to product for cleaning the switches. Worked great, never had complaints from customers.
They were a great oscillator in their day.
By the way I was fortunate enough to meet Dave Packard personally and had a brief conversation with him....Really nice guy.
Good luck with your restoration.


gtracyca <gtracy@...>
 

Is there a group for HP plotters? I have a HP 750C Plus and I"m looking for drivers for it.
Thanks.,