Hi to the group new to this group I have an HP 8640b the frequency range switch has dropped some of its contacts and looking with the times 30 loop on the plastic discs it looks like I'm missing a couple of contacts that I could not find inside the chassis anybody have any information on how many contacts on each of the three discs that are inside that machine appreciate any help thank you

There are some good articles on the Internet regarding this problem.

Also there is a web site for a company that offers serving of these units, for a price. You ship the entire unit to them and once repaired they ship it back.

Start up your favorite Internet search engine and fire away.

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Hello Mark,

Indeed there's a lot on the net about those.

Here are some:

Good luck!

Renaud

Renuad,

Those are all great places to start. I have one of these units and I used the technique described on these articles. The epoxy/glue option works very well. I did this on all of the wipe contacts whether they were ready to separate/fall off or not. Good insurance down the road for the original ones to stay in place.

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Dave Wise

Hi,

I bought one British made last year with obviously such missing ones, (not falling from the body either Mark!) and was also prepared to work there. Then another one presented itself (US made) cheap here in France. What could I do? I bought it and it happens that it's working fine. Even the plastic gears are good. So I neglected the other but I will do it. They are wonderful stuff. Mine have both the 1 GHz option.

Do tell us how it's going Mark

Renaud

Mark,? i found some spare HP switches on ebay that used those same contacts.? I cut them out and epoxied to my range wheels.? Loctite makes a clear 2 part plastic bonder that works very well and because its clear, is not very noticeable installed.

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-A

Adam, I believe that contacts from the slide switches of HP8012B and 8013B would do too but that should be verified. What are the reference of those you found please?

Renaud

The switch i removed the contacts from was the 8640B slide switch used on the AM/FM modulation slider.? There are some other instruments that use this same contact as well, but do not have the details.? There was a thread about it a few years ago.

Thanks Adam.

So a slider again. It should be possible to find them from more dead HP devices.

But difficult now to find cheap ones even "dead".

Renaud

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