Author Topic: Is AE sealed transmitter capsule repair possible?  (Read 651 times)

Offline KaiserFrazer67

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Is AE sealed transmitter capsule repair possible?
« on: April 15, 2017, 07:20:58 PM »
Hi all;

I have four Automatic Electric Type 41 transmitters which have excessive crackling; two of them are so bad as to render a decent conversation impossible.  I've tested them on a phone I know to otherwise have no problems.  These are the only Type 41 transmitters I have, and they're all bad to some degree.  The 81 and 810 capsules I have seem to be okay.  Thank God the newer ones can be used in the Type 40 and 50 phones.

Just wanted to know if its possible to do any kind of servicing on these things before I consign them to File 13.

If there's anyone who might want them anyway, please PM me with your address and I'll gladly send them to you free of charge, including shipping.

Thanks much!
-Tom from Oakfield, Wisconsin --  My CO CLLI & switch: OKFDWIXADS0--GTD-5 EAX

"Problems are merely opportunities in workclothes." -Henry J. Kaiser

Offline Jim S.

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Re: Is AE sealed transmitter capsule repair possible?
« Reply #1 on: April 15, 2017, 08:50:53 PM »
Did you try rapping the transmitter edge(sharply) against a hard surface. This breaks the carbon back into granules.
JMO,
Jim S.
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Offline KaiserFrazer67

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Re: Is AE sealed transmitter capsule repair possible?
« Reply #2 on: April 15, 2017, 09:33:22 PM »
Did you try rapping the transmitter edge(sharply) against a hard surface. This breaks the carbon back into granules.
JMO,
Jim S.
Yes I have, to no avail.  I also made sure the electrical contact surfaces on the center point and the outer rim were clean.

Interestingly enough, blowing into or speaking into the transmitter briefly intensifies the crackling.
-Tom from Oakfield, Wisconsin --  My CO CLLI & switch: OKFDWIXADS0--GTD-5 EAX

"Problems are merely opportunities in workclothes." -Henry J. Kaiser

Offline TelePlay

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Re: Is AE sealed transmitter capsule repair possible?
« Reply #3 on: April 15, 2017, 09:37:38 PM »
And don't toss them. You can set them aside in case you need the carbon granules. This small vial of supposedly transmitter carbon granules has been on eBay for 20 days now as a BIN, hasn't sold. But the price gives you an idea of those little particles are worth, in general.

     http://www.ebay.com/itm/222453829586

There is at least one topic somewhere on the forum about removing the caps, "fixing" the carbon and resealing it. Must be at least 5 years ago it was posted.
            John . . .

              

unbeldi

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Re: Is AE sealed transmitter capsule repair possible?
« Reply #4 on: April 15, 2017, 09:39:19 PM »
One method I have been wanting to try, but haven't yet, is to seal the transmitter into a small plastic bag, and then place it into an ultrasonic cleaner for a long treatment.  The metal encapsulation may be too much of a mechanical shield, but perhaps the sound waves are still strong enough.

Offline TelePlay

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Re: Is AE sealed transmitter capsule repair possible?
« Reply #5 on: April 15, 2017, 09:47:27 PM »
Interestingly enough, blowing into or speaking into the transmitter briefly intensifies the crackling.

I was doing some audio work on transmitters and recorded these rough wave forms of different transmitters from 0 to 5000 Hz. Keep in mind that a lot of the visible changes are due to the speaker response over that range, the speaker profile shows in the recorded waves as well as the transmitter response.

I'm showing this here because I had on transmitter, a Stromberg Carlson, that was toast and you can see it produced nothing but static over the full scan range. Kellogg, SC and F1 transmitters were tested in this image. So, you are correct in that observation. A toasted transmitter will produce static but will not convert sound to voltage, the center wave form.
            John . . .

              

Offline TelePlay

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Re: Is AE sealed transmitter capsule repair possible?
« Reply #6 on: April 15, 2017, 09:57:01 PM »
One method I have been wanting to try, but haven't yet, is to seal the transmitter into a small plastic bag, and then place it into an ultrasonic cleaner for a long treatment.  The metal encapsulation may be too much of a mechanical shield, but perhaps the sound waves are still strong enough.

Tried that, didn't work. Without the liquid solution being in direct contact with the capsule, it is basically shielded by the plastic/air gap.
            John . . .

              

Offline Jim S.

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Re: Is AE sealed transmitter capsule repair possible?
« Reply #7 on: April 15, 2017, 10:03:31 PM »
A vacuum sealer might take care of the air gap.
JMO,
Jim S.
You live, You learn,
You die, you forget it all.

Offline KaiserFrazer67

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Re: Is AE sealed transmitter capsule repair possible?
« Reply #8 on: April 15, 2017, 10:10:27 PM »
And don't toss them. You can set them aside in case you need the carbon granules. This small vial of supposedly transmitter carbon granules has been on eBay for 20 days now as a BIN, hasn't sold. But the price gives you an idea of those little particles are worth, in general...

There is at least one topic somewhere on the forum about removing the caps, "fixing" the carbon and resealing it. Must be at least 5 years ago it was posted.
At least I'd be able to do something constructive with them.  I did manage to fix my Kellogg Redbar's transmitter that way, but that particular kind was easy enough to open up and re-seal, since they're designed to be repaired internally.

Incidentally, my Kellogg's transmitter was crackling excessively because the little fabric patch holding the granules in place wasn't doing its job, and the granules got out into the main part of the transmitter cavity:  http://www.classicrotaryphones.com/forum/index.php?topic=17028.msg184199#msg184199  I'm wondering if something similar has happened with the AE 41s.  I'm guessing the general concept behind their construction must be similar.

I don't know if the 81s and 810s I have are working just because they're newer, or if they were designed to overcome some of the same problems I'm having with the Type 41s.
« Last Edit: April 16, 2017, 12:27:47 AM by KaiserFrazer67 »
-Tom from Oakfield, Wisconsin --  My CO CLLI & switch: OKFDWIXADS0--GTD-5 EAX

"Problems are merely opportunities in workclothes." -Henry J. Kaiser

Offline TelePlay

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Re: Is AE sealed transmitter capsule repair possible?
« Reply #9 on: April 15, 2017, 10:14:12 PM »
A vacuum sealer might take care of the air gap.
JMO,
Jim S.

Don't think so. Ultrasonic cleaners work by sending sound waves through the liquid and when them come into contact with a surface, that is where the micro bubbles are created from the energy and their collapse is what jars the debris/dirt loose. If the bubbles are cavitating on the surface of the bag, no energy or vibration would make it to the capsule much less into the carbon. Actually, putting the transmitter directly in the liquid would clean the metal surface but do little for what's inside.

Something that provides macro vibration, such as a high wattage speaker concentrated on the capsule would have more effect on the entire capsule and not just the surface - same as rapping or tapping but massive and over a long period of time.
            John . . .

              

Offline Jim S.

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Re: Is AE sealed transmitter capsule repair possible?
« Reply #10 on: April 15, 2017, 11:06:46 PM »
I had an old Signal corp telephone tester.
ISTR that it had 135 VDC  to zap  the transmitters with.

JMO
Jim S.

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You die, you forget it all.

unbeldi

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Re: Is AE sealed transmitter capsule repair possible?
« Reply #11 on: April 15, 2017, 11:13:13 PM »
Don't think so. Ultrasonic cleaners work by sending sound waves through the liquid and when them come into contact with a surface, that is where the micro bubbles are created from the energy and their collapse is what jars the debris/dirt loose. If the bubbles are cavitating on the surface of the bag, no energy or vibration would make it to the capsule much less into the carbon. Actually, putting the transmitter directly in the liquid would clean the metal surface but do little for what's inside.

Well, what you are describing is the action of ultra-sonic cleaning.
We don't want to clean, but simply provide vibration.  Clearly the ultrasound penetrates for some distance, you can hear it at several feet distance.  There is no reason the sound should not penetrate the sample.  The question is whether it is sufficient or even effective in principle.

Offline KaiserFrazer67

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Re: Is AE sealed transmitter capsule repair possible?
« Reply #12 on: April 15, 2017, 11:58:10 PM »
I appreciate everyone's input; thank you.

However, the problem with these doesn't seem to be the granules being caked together and needing to be knocked loose; I can hear them when I gently shake the capsules, like salt in a shaker.  I'm thinking the opposite situation may be the problem:  that they have gotten loose from the area where they are supposed to be in the first place, and are now not only roaming around inside the sealed transmitter cavity, but also considerably reduced in quantity in the area where they're supposed to be concentrated in the first place.  That was exactly the case with my Redbar transmitter capsule (see my link to that thread above).  Thankfully, since the Redbar one could be completely disassembled, I was able to fix the problem (for now) once I was told (by reading a similar thread) where and how the granules are supposed to be contained.

The AE 41, however, is a completely sealed unit.  I can (barely) grab the small silver center contact cap with a pliers, and discovered that it won't unscrew, but it can turn (see teeth marks on it in the photo below).  However, I can also hear what I assume to be carbon granules scraping along the inside of the crimped area when I do this.  It sounds just like sand or grit grinding and scraping between two surfaces, and the only thing in there would be the granules.

So my only recourse IMO would be to uncrimp or cut it (probably easier from the grille side), open it up and save the granules for use in an early-type fully-serviceable transmitter.
« Last Edit: April 16, 2017, 12:35:59 AM by KaiserFrazer67 »
-Tom from Oakfield, Wisconsin --  My CO CLLI & switch: OKFDWIXADS0--GTD-5 EAX

"Problems are merely opportunities in workclothes." -Henry J. Kaiser

Offline TelePlay

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Re: Is AE sealed transmitter capsule repair possible?
« Reply #13 on: April 16, 2017, 12:03:18 AM »
Well, what you are describing is the action of ultra-sonic cleaning.
We don't want to clean, but simply provide vibration.  Clearly the ultrasound penetrates for some distance, you can hear it at several feet distance.  There is no reason the sound should not penetrate the sample.  The question is whether it is sufficient or even effective in principle.

I would certainly agree with that. I'm thinking of the ultrasonic cleaner I use which is a one quart tank and a relatively low power generator operating at 40 KHz. A more powerful generator at a lower frequency that is capable of being operated in air might do a very good job of vibrating the metal capsule and it's carbon contents. A hand held sonicator with a tapered to a near point working tip placed directly on the capsule would do that. However, those run around $850. Then again, one of those switchboard buzzers might be enough to vibrate the granules apart. My ultrasonic cleaner did not work.
            John . . .

              

Offline TelePlay

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Re: Is AE sealed transmitter capsule repair possible?
« Reply #14 on: April 16, 2017, 05:22:33 PM »
The AE 41, however, is a completely sealed unit.  I can (barely) grab the small silver center contact cap with a pliers, and discovered that it won't unscrew, but it can turn (see teeth marks on it in the photo below).  However, I can also hear what I assume to be carbon granules scraping along the inside of the crimped area when I do this.  It sounds just like sand or grit grinding and scraping between two surfaces, and the only thing in there would be the granules.

Your AE transmitter is similar to my toasted 4-35 SC except the center post on the SC is not like the AE. It seems the SC transmitter was assembled by crimping a ring around the front of the transmitter, locking the front grill to the body. There is not other way to take the SC apart and from the photo of your AE, it seems to have the same type of ring crimped around the front. When shake the SC, I can not hear the carbon inside.
            John . . .