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Old 9th Jan 2017, 1:12 am   #21
dagskarlsen
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Default Re: WWII Type "F" MK II Handset question

Mine is ringing.
I have to look at my handsets, it might have been changed due to bat transmitter capsule.
dsk
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Old 10th Jan 2017, 6:55 am   #22
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Default Re: WWII Type "F" MK II Handset question

To late to change spelling from bat to bad

Ill guess this is the original handset:

Cord is bad, transmittier is bad, plug is missing, so I ca not getting this OK unless using newer parts.

dsk
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Old 10th Jan 2017, 8:44 am   #23
Dave Moll
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Default Re: WWII Type "F" MK II Handset question

Yes, that looks about right. Here is one of mine...
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Old 10th Jan 2017, 10:04 am   #24
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Default Re: WWII Type "F" MK II Handset question

Quote:
Originally Posted by Dave Moll View Post
Here is one of mine...
I see your HMT has the 'official' WD modification DLR5 rocking armature receiver fitted. One of mine has, and one hasn't.

Was this mod done post-WWII? 1950s, perhaps?
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Old 10th Jan 2017, 10:31 pm   #25
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Default Re: WWII Type "F" MK II Handset question

Quote:
Originally Posted by Dave Moll View Post
Yes, that looks about right. Here is one of mine...
If the handset has a 'pressel' switch , it is off a Tele D MkV or Tele L. The correct one for the Tele F Mk 1 or 2 has no 'pressel' switch and is similar to a GPO Tele 184 but has the sloping mouthpiece as per the one in Dave's photo. The handsets, being 'unplugable' often got swapped in the field if there was a fault. Happy days using them in the field when I was wearing the R Sigs cap badge. The Tele F was usually mounted in vehicles - there was a metal bracket with a turned up lip which followed the outline of the base with a web strap and buckle that went over the top to stop it moving when the vehicle was in motion.
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Old 11th Jan 2017, 8:50 am   #26
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Default Re: WWII Type "F" MK II Handset question

Actually the one I showed, from my Telephone Set "F" Mk I, has a blanked-off pressel. This is also the case with one of my Mk IIs. The rest have handsets looking nearer in design to the standard handset 164 - though with four separate internal connections rather than the 164's common return, and the sloping mouthpiece rather than a cup.
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Old 11th Jan 2017, 2:08 pm   #27
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Default Re: WWII Type "F" MK II Handset question

The 'Tele 184' looks like a 'Tele 164' but has four connections - two for transmitter and two for the receiver and was the basis for the original handset on the Tele F - fitted with the balanced armature receiver and sloping mouthpiece. I doubt the blanked out pressel was an original fitting but a like 'bodge' in the field. It was the sort of thing our guys did to get out of a fix.
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Old 21st Jan 2017, 6:26 pm   #28
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Default Re: WWII Type "F" MK II Handset question

I connected my phone to my home phone system, and it rings when I call the number. When I pick up the receiver before calling, the dial tone is very very faint. Does anyone know why that might be? Thank you!
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Old 22nd Jan 2017, 3:46 pm   #29
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Default Re: WWII Type "F" MK II Handset question

It is no absolute answer on that question, but you may have a receiver needing adjustments.
The diaphragm shold be close to the magnets, but not touch, distance may be adjusted by turning it upside down, or adding or removing rings of paper. (cut your own, if you need some)

dsk

Picture from Naval Electrical Pocket Book 1953
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Old 25th Jan 2017, 4:31 am   #30
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Default Re: WWII Type "F" MK II Handset question

I flipped the diaphragm disk over (which was much smoother on the other side) and did not screw it down all the way and it was much louder. Thank you!

Now one more question - When a person calls and I answer the phone, I can hear them talk, but they cannot hear me talk. I cannot year myself talk into the handset. Is there something I can do to check this out? Thanks!
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Old 25th Jan 2017, 8:46 am   #31
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Default Re: WWII Type "F" MK II Handset question

First of all, have you installed the battery, 3-4.5V should do, polarity is not important. (picture in an earlier post)
If yes it may be a bad transmitter capsule (Microphone), or something in the wiring, e.g. a bad cord. You should hear yourselves (even with no line connected) The hook switch contains several switches, among them one who switch off the battery when the handset press on the switch. Leaving the handset off may empty your battery. Do not put in a battery voltage of more than 4.5V! The circuit is designed for 3V.

If this not solves the problem you have to measure a bit until we locate and corrects the error. In that case, do you have any instrument, or test lamp glowing at 3V? Have you used this instrument before?

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Old 25th Jan 2017, 8:53 am   #32
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Default Re: WWII Type "F" MK II Handset question

In the Telephone Set "F", as with other field telephones, the transmitter is powered from the local battery, so check that it is supplying the correct voltage. The original transmitter inset is designed to operate at 3V, but a higher voltage may be needed with other, especially if you have a modern electret replacement inset (which needs a minimum of 4½V).

If the set is working correctly, sound (or blowing) into the transmitter should be audible in the receiver even without the set connected to anything else - useful for testing purposes.

edit: DSK posted while I was composing my reply
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Old 29th Jan 2017, 8:18 pm   #33
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Default Re: WWII Type "F" MK II Handset question

I appreciate the helpful ideas in Response to my transmitter problem. I have hooked up D cell batteries in series and verified with my multimeter that one set generates 3 volts and another 4.5 volts. The original wires that connect to the batteries are in good shape. On the handset, with the transmitter out, the contacts that the transmitter sits on read the correct voltage with my multimeter. When I short the contacts together I hear a short tap noise in the receiver. Regarding the transmitter itself, it fails a continuity test (but I don't know if it should). When I hook leads up to the transmitter and the handset contacts I (not being knowledgeable in this area) would expect the multimeter to register some level of voltage fluctuation when I blow or speak into the transmitter since the job of the transmitter is to convert the diaphragm vibrations into electrical signals. But nothing happens. Is there a way to check the transmitter itself out? Thank you!
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Old 29th Jan 2017, 8:24 pm   #34
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Default Re: WWII Type "F" MK II Handset question

The transmitter in these telephones (and indeed in most older telephones) is known as a carbon microphone. It acts as a variable resistor, it does not itself generate a voltage.

The transmitter should not appear as a short circuit (0 Ohms) on an ohmmeter, but it shouldn't be open (infinite resistance) either. I would expect a few hundred to a few thousand ohms. If it is open-circuit, then it has failed.

Often if you connect an ohmmeter to a (working) transmitter and tap the latter, the resistance will change (and stay changed) as you shake the carbon granules up. With an analogue ohmmeter you can often see a change in resistance if you blow or speak loundly into the transmitter.
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Old 29th Jan 2017, 8:56 pm   #35
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Default Re: WWII Type "F" MK II Handset question

Quote:
Originally Posted by cfrlar1 View Post
Is there a way to check the transmitter itself out?
As Tony stated this is a carbon microphone (Telephone people calls it a transmitter) You may see some detail about the transmitters on pages like this:
http://www.schoolphysics.co.uk/age11...one/index.html
http://www.vias.org/albert_ecomm/aec...vices_006.html

The testings you have done limits the possibilities to 1: bad cord, 2: bad contact springs, or 3: bad transmitter element.

1: test by removing the tranmitter, and short the contacts, you should hear a click.
2: try to see if the contact spring touches the main body of the transmitter, and on this unit a contact pin enters the center contact of the capsule.
3: Shake the transmitter, and listen for the sound of rattling carbon granulates, if nothing heard roll it on a cardboard or another uneven surface to try to loosen clogged carbon. Try it again. By my opinion these transmitter elements are not the best ever made, so it may be weak or defect. An OK transmitter should have a current of 20-50 milliamps. You may increase voltage to get this current. If you are trying to put in a carbon transmitter from a regular telephone you may have to adjust the voltage to get the right current. I did put in a different transmitter in mine, one from a door intercom.

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Old 29th Jan 2017, 9:06 pm   #36
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Default Re: WWII Type "F" MK II Handset question

Certainly, from what has been said so far, it would appear that the transmitter (carbon microphone) is dead. Probably, the only way forward is replacement.

As mentioned previously, an electret inset (sold as transmitter 21A - red version) can be substituted as long as the battery voltage is at least 4½V. The reaseon for using the red version is that the outer casing can be removed to allow the inner module to fit in the transmitter housing.
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Old 9th Feb 2017, 1:13 am   #37
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Default Re: WWII Type "F" MK II Handset question

Everyone, I wanted to post an update based on your awesome advice! I initially could not hear any carbon grains rattling around inside the transmitter. Holding the transmitter in my hand wrapped in a cloth, I placed it against the pad of a hand-held power sander and let it vibrate for a few seconds. That worked! I was able to shake it and hear the particles move. Next, I hooked it up with a 3v battery (two 1.5 volt D cells), but nothing. I added a third D cell battery to bring it up to 4.5 volts, and that worked! So now the phone is fully operational. Thank you all again!
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Old 9th Feb 2017, 8:47 am   #38
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Default Re: WWII Type "F" MK II Handset question

I'm glad to know you got it working. I like the idea of the sander (presumably without the abrasive surface!) as a vibrator to agitate the carbon granules.
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Old 9th Feb 2017, 6:28 pm   #39
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Default Re: WWII Type "F" MK II Handset question

New people, new solutions, that is the evolution!
Thank you for that idea!

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Old 9th Feb 2017, 6:34 pm   #40
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Default Re: WWII Type "F" MK II Handset question

Yes, I like the idea of using a sander to shake up the transmitter. Next time I have one that seems caked solid I will give it a go.

One of R. V. Jones's telephone pranks was to get people to sing loudly into the mouthpiece 'as the carbons are seizing up'. Doesn't do a darn thing, of course other than make the victim look like a right idiot.
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