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Reconstruction of a ceramic wafer switch.

Like the title states.

I have not done this for a long time and the last time I did I only needed to repair just the wiper fingers. Well, this time I need to reconstruct most of the wipers on one ceramic wafer and the shorting plate.

This is for an old SB-1000 Linear Amplifier, It also looks like some one with very little skills in the field attempted repairs on their own by looking at the other locations.

The owner of this unit really wants it correct and of course, the parts are obsolete. It must of been a common problem because I find hit after hit on the google from those looking for these switches. :)

So, I have some new ceramic switches here now that I will be drilling out the rivets for the wipers etc..

This is the problem however, the wiper shorting plate also took a hit and got burned, warped etc.

What I will be doing is drafting out a new plate on the PC, and using a thick sheet of brass. I will laser print image at 1:1 and iron it onto the plate as a template.

Now because I will be doing this with a rotary tool in a vise and XY table. I need to glue this plate to a piece of wood or phenolic material to hold it in place while milling it out.. Of course, I'll need to where my head magnifiers for this.

When I get done with the edge cutting, I need a way to remove this plate from the block by softening or some how separating the plate mildly with out bending it, do any of you know of a way that will soften the glue? I was thinking of Acetone? But I am not sure about that one?

When done, I will be silver plating this. I also need to get some very small screws and nuts like around #0-80 for example. I don't feel like riveting it back together..

So, does my idea of doing this sound plausible if I can find an easy way to remove the epoxy that will be holding the plate down during the milling and edging process ?

Jamie

Reply to
Jamie
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Perhaps hot glue would suffice ??

Reply to
Rheilly Phoull

My experience is that hot glue can be rather difficult to remove completely from bare metal like brass or copper.

Many people in the wood working field just use double stick tape to hold parts together for temporary work. I've even seen it described as being suitable to hold small parts that were being cut via a router.

You can probably get double stick tape to let go by applying heat with a heat gun. I've found that to be a very effective means to remove old shipping labels from cardboard boxes that I want to re-use for shipping something else.

--

Michael Karas
Carousel Design Solutions
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Reply to
Michael Karas

heat it with a blow torch, or hotplate. that glue will give up before it gets red hot.

Is this piece of such a shape that it can't be cut with snips or a nibbler?

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Reply to
Jasen Betts

My vote would be for glycol phthalate wax. It goes on hot like a Sears glue gun, but it's water soluble, so it's easy to get off. I have an

8-inch stick of it that I've used for years, but Master Bond sells water-soluble two-part adhesives as well.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510
845-480-2058

hobbs at electrooptical dot net
http://electrooptical.net
Reply to
Phil Hobbs

No, it has to be routed out, shears would make a mess out of the edges. These edges must slide under the contact fingers and the plate must stay conformed.

Jamie

Reply to
Jamie

"AL-80 replacement bandswitches fit and they are easier to get" That's a quote from:

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If the quoted sentence is correct, it should save you a lot of work.

It refers to the Ameritron AL-80 being a clone of the SB-1000. (vice-versa according to Tom Rauch: "I designed the AL80A first, and then sold the kit-only rights to Heath. So the Heath is a "licensed copy" of the AL80A." )

Ed

Reply to
ehsjr

Yes, I was made aware of the design being the same however, it seems that the stock for replacement switches for the AL-80A are also depleted!

I can't seem to find any available out there.

Nice to meet the guy that designed it though. ;)

P.S.

I own myself, a AMERITRON AL-80A and that is still operating fine with the exception of the zener diode circuit pulled out of there and replaced it with a circuit and protective fuse. It saves a lot on those studded odd ball zeners when it decides to arc out if you don't let it warm up long enough before you hit the PTT line :)

Jamie

Reply to
Jamie

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