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A serious (as in not troll) requestfor help w/ultrasonic transducer

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Many of us use a 50 year old ultrasonic cleaning machine manufactured by L&R in New Jersey.  It is STILL accepted by Rolex and everyone else.

The issue is that the transducer element fails over time.  Sometimes it is an epoxy fail, but often the "rock" is damaged and cannot be reused.

Below is a picture.  We refer to it as a "donut" because the can it sits in has a channel w/ thru hole for the absket motor shaft to pass through (the basket rotated beneath the assembled transducer).

The Dimensions are:

Height  28mm
OD  65 mm
ID 21 mm

Any thoughts on sources, replacements ar alternatives would be greatly appreciated.  These were set to 87 kHz.



if your doing this for money then replacing it is kind of like messing with a tuned cavity, you can't be sure of if there is no areas of stronger force if you change the transducer and its damping effect on the system.

i doubt you will get a certifiable replacement easily

a practical test would be to put foil in there and see how it does when you compare two different transducers. if the rolex one damages the foil in the same spots as the replacement in the same time, you are probobly good. must be done with same chemicals at same temp (stir it well before test)

I suspect it might be bull shit unless you take way too long and use bad chemicals, because a bond wire in a IC is finer then anything that can ever be in a mechanical watch. For most IC you don't see even a small failure % on sensitive parts up to the 6 minute mark.

I assume what you are worried about is dodgy plating coming off.

The frequency is more trouble on large structures, maybe. But the only thing I can think of in a watch that is sensitive is the long spiral spring. But that is usually replaced instead of cleaned anyway right?

the other sensitive part is the face with the inks and stuff, but that is probobly a question of not leaving it in there for too long and using mild chemicals.

to measure the frequency connect a oscilloscope to the power system (just make sure its voltage is not too high for scope)

getting a very thin foil in there will show damage quickly on it to use as a test particle I think. You can do alot thinner then aluminum foil to try to see a effect quicker.  That you can position on a articulating arm (dial indicator arm) with a aligator clip on it

I can't help feeling that 50 years old is ancient, and whatever parts it contained would be long out of production unless you can find new-old-stock somewhere. Your best resource would be the watch repair community rather than an electronics forum.

A quick google for ultrasonic cleaners shows that new ultrasonic cleaners for watch parts are readily available, either in the USA (expensive?) or from China (less expensive?). It might be easier to buy a new machine than to try repairing an old machine?

When I watch YouTube videos on watch repair, it doesn't seem there is anything too complicated about them. You put the parts in the baskets, put the baskets in the machine, and let it run until the cycle is over. The cleaning solution is going to be the same with new or old, and I'm not really sure how metal parts can be damaged?

(The only thing that boggles my mind is how someone can completely disassemble a watch, clean the parts, and put it all back together again with all those minute screws, jewels and other parts that have to go back in exactly the right order. I find it hard enough just replacing a watch battery.)

Thanks.  I know about the foil test.

The problem faced by watchmakers is that this machine is accepted by all brands.  TO replace it with a new unit that is accepted cost from $8K up to over $12K.

I am not repairing these, there is a business that does only these.  While I am hoping my unit is down because of a failed capacitor array (to be checked this week), the next failure point is the head.  And the tech and his Dad have been trying to come up with replacements for broken transducers since they ran out of their stock of replacements.

I am asking here because I want these units to continue to be available rather than force more watchmakers out of business or have to line the pockets of the brands who have a vested interest in the new machines.

I do not need the machine for accounts since I am retired, and I do have a work around for getting my parts chemically clean (ultrasonic tank bath then the 4 jar machine).  Cumbersome, but it will work.  Those in business cannot afford the lost time.

If anyone know a source, it may make business sense for the repair business to have 50 or 100 donuts made.

rolex is like bently they have a procedure and approved tool for everything you can't service customers if you go out on your own without at least very hard evidence

you will be dealing with a 800$ an hour lawyer as your customer


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