Mayfair FT-111 Earpiece Repair

[DMcMahon]

The cable has parted company with the little earpiece that came with my Mayfair FT-111.

Has anybody ever sucessfully got inside one of these earpieces and been able to reconnect the broken wires ?

David

[TonyDuell]

With some of them, the case of the earpiece is in 2 parts pressed together. A thin blade in the crack between them will separate the parts. Then the diaphragm slides out and you can remove the magnet/coil assembly. If you're lucky there will be 2 obvious solder pads on the underside of that to connect the wires to.

[Station X]

I have a bag full of vaguely similar NOS earpieces. You're welcome to a couple FOC. You pay postage.

[Silicon]

Those earpieces were generally available in two types.

A low impedance moving coil version and a high impedance crystal version.

[Station X]

I'll check their impedance.

[Reelman]

There was also a rarer medium impedance version which tended to look a little "posher" . The low impedance ones usually had either a 2.5mm or 3.5mm plug. I've never been impressed with the sound quality and have always meaned to try a modern ear bud to compare.
Would love to find any type with the tiny 2 pin plug as used on the Russian and Micronic sets.

Peter

[DMcMahon]

Armed with confidence from Tony's post I will try and split the earpiece and hopefully do a repair. I have tried quite strong pulling and twisting but no movement.

Somewhere I have several other earpieces so in no desprate need of a replacement if my attempted repair falls through, so thankyou very much for your kind offer Graham but hold fire on that at the moment.

David

[Reelman]

You should be able to separate at the gold ring but it may be glued so try prising all around. I did it myself years ago so it can be done. The older Crystal earpieces had a screw panel to give access to the solder pads. Although the modern ones look very similar to their ancient counterparts I notice that the panel is now no longer removable and the ear bit no longer unscrew for cleaning!

Good luck David!

Peter

[Station X]

Originally Posted by Station X

I'll check their impedance.

The ones I have are all low impedance. The DC resistance varies a bit as some earpieces have longer leads than others. I'd say they're nominally 8 ohms.

[DMcMahon]

Using blade from Stanley knife managed to split/prise open the earpiece.

The earpiece measured OK at around 6 Ohms so remade the ends of the 2 wires and soldered them back on and measured 6 Ohms again at the 3.5mm jack plug.

Fitted two 1.5V C size batteries into the Mayfair and powered it up for the first time.

Was not expecting much because it was sold as "not working" but no details of what that meant.

Tried three 3" tapes and got some hiss/hum at high volune settings but no recording Playback sound, unsure if there were any recordings on these tapes so tried a fourth tape and this did have recordings on it that played back, but sounded far too fast (but no idea what machine the recording would have been done on).

All sound was only heard on the internal loudspeaker, nothing heard from the earpiece, rechecked the earpiece resistance and found it open circuit, opened it up again and found one of the wires had broken off, so resoldered it back on.

Retried earpiece listening again but no sound, you guessed it, a wire had broken off again at the earpiece. The wire is very fine and when soldered very easy for it to break when moved/stressed, so next repair attempt may try gluing the wires to reduce stress on the soldered connections.

Even thogh the tape control is working, there are several issues :-

1. Playback speed is quite erratic in real time (appreciate that the speed will vary over time due to it being rim drive.

2. Not sure if the manual adjustable speed control is doing anything to the speed.

3. During Play when Stop is pressed, often tape does not stop although any playback sound does stop, the tape motion does stop when Stop is pressed a second time.

4. Rewind works but tape is quite bouncy acrosss the spools and sometimes quite squeaky.

5. During Rewind, often pressing Stop does not stop the tape motion properly, it stops but straight away carries on playing the tape (but no playback sound) .

6. The tape looks to be sitting too high up on the Take Up spool.

Currently cannot find the correct microphone so have not yet attempted recording.

David

[DMcMahon]

Third attempt at soldering the earpiece wires seems to be holding up and the earpiece is working well.

Found the Mayfair microphone and microphone recording works well (remote start button also works) but the Playback sound sounds quite slow (only tried my voice speaking so far) must check the battery voltage when it is running and maybe try and check the actual tape speed. The manual tape speed adjustment definately does not appear to do anything.

The instructions say that the earpiece/earphone can be plugged in during recording to monitor the recording, but in practice the earphone must be plugged in (to disable the speaker) otherwise get loud feedback howl, even when the microphone is well away from the unit.

Another operational defect is that whenever the batteries are inserted the tape mechanically starts playing (no sound) maybe related to defect 3 & 5 above, must try some contact spray cleaner on the switch bank.

David

[G6Tanuki]

The flex used on those earpieces only had a rather sparse number of strands; these had a tendency to fatigue-fracture in the few inches close to the earpiece where the amount of repeated bending/twisting was highest, and so it was my usual thing to cut back the flex by several inches before re-soldering it.

[DMcMahon]

Thank you good input, during the repairs I have cut back maybe around 1", if it breaks again I will cut back further.

David