Headphone/microphone hearness for # 19

[Bob Carriere]

But I still have questions....

Bruce thanks for the schematics.....much better than the crude one I drew up .

... I have used DeOxit on the brass contacts but did not seem to clean up much....... I may try the old "Brasso" next with a light touch.

Also I have both the No 1 Lollipop and the Big bulky No 10 fist type.
For the sake of this discussion I will focus on the lollipop type. I actually had a No 1 that was so dried up it was useless.... so I broke up the snatch plug and removed some section of cloth covering to see wiring color and physicaly and visually trace properly....

One more basic observation on the color wiring scheme

Referring to Bruce's schematics... top right hand corner.

When looking at the snatch plug as shown on the schematic...

Pin no 1 is Blue
Pin 2 is Green
3 is Black
4 is White
5 is Red

So is it correct to say power comes from connection A in the control box to pin 2 Green on the snatch plug.... goes through the earphone wired in series and back by means of the Black wire (common/ground) pin 3 and connection C.......?....... so applying power to pin 2 and 3 on the plug should give me sound on BOTH earphones....? which I can't get !!!!

Now for my observations/questions......please be patient....

When I apply power from the earphone cable from the radio to the RH earphone (RH on the schematic) directly to the two screws the RH earphone works. When I apply contacts to the black brass no 3 in the plug and the other to the screw of the RH earphone it works.

If I apply the same source of power directly to the LH earphone it will NOT work.......

I have done the same process to another no 1 and 2 other no 10 with the same results.... only one earphone can be powered.

I can establish contact with the pin no 3 black on the plug on all other 3 set BUT cannot connect power to any of the other contacts and get sound.

Leaving out pin 4 and 5 .. white and red.... I only have 2 other possibilities the blue or green..... but the blue seems to be cut off by the microphone switch..

I cannot understand why I cannot get sound off the LH earphone..... not all 3 sets could not be defective.....

If they are wired in series..... if I applied power to the RH black earphone and to the green wire leaving the LH earphone I should have sound coming out of both earphone..... but I get nothing...?

Why can't I ear sound from the LH earphone when I connect power directly to both screws/contacts of the earphone...? but it works on the RH earphone.

Is my power source from the transistor radio too weak to power both earphones......

Remember I repeated the same negative results on 3 other sets besides the one I took apart....?

I am sure glad not to be working with High Tension wiring as I would be fried by now.

Speaking of fried.... last Saturday when I had friends over to chat about WS 19 sets I showed them a Dynamotor that my Dad had used in the 50s/60s to engrave his initials on his tools using the HT 2 of the Dynamotor. So I fired it up with a CPP-2 power supply and the Dynamotor wirled into life......on 550v you can put the two HT alligator clips together than slowly pull them apart with a nice white/blue steady spark for about 5 or 6 mm before it stops..... I was encouraged to turn if off and put it away.

Awaiting your comments and guidance.

Bob C.

[RHClarke]

Originally Posted by Bob Carriere

...on 550v you can put the two HT alligator clips together than slowly pull them apart with a nice white/blue steady spark for about 5 or 6 mm before it stops..... I was encouraged to turn if off and put it away...Bob C.

It was a good thing Joyce was not home at the time, Bob. Yes, the pretty white spark (capable of welding steel plate) was amusing for the first few seconds, but when you started to laugh manically, we got a bit worried...

Thanks for hosting the session. It was, well, electrifying.

[Bruce MacMillan]

I tested a #10 headset using an ohmmeter and there was continuity between pins 2 & 3. There was continuity across the right hand earphone and the left hand earphone, measured at the screws.

Take your multimeter and use the low ohms range (I trust you have one )

Measure from the common to test points 1, 2 & 3. If 1 is good then there is continuity across right headphone. Go to point 2. If good fine but if open there could be a break in wire between earpieces. If 2 is good then measure point 3.

At each point your should have a low resistance reading. Using the ohmmmeter is a better way to test the headset & cables than listening to CBC.

If the set measures high resistance (open circuit) then scrub down & prepare for surgery. Are the headset's Canadian (Chamois cushions)?

[Bob Carriere]

....back to the work bench to play with the Ohm metre.

Bob C.

[Bob Carriere]

I Bruce.... last question first......

The lollipop No 1 that I am carefully disecting has some kind of black velvet removeable covers....

The other 2 No 10 have the chamois and another relatively new acquisition No 1 also has chamois on the ear pads.

To prevent confusion I will stick to the disected No 1 set.

See the attached picture of my findings..... note that I have added a letter A for the post on the RH earphone....then continued to the other 1, 2, 3 and added a Post plug 2 for the end return to the plug.

...so the left hand earphone seems to be open..!!!

Before I put on the gloves for internal surgery to the LH earphone.......

....when I played the radio through the RH earphone and went on to connect directly to the post 2 and 3 of the left hand earphone NO sound came out.... i.e. infinity readings. Now without taking apart the other earphone sets I got the same results from the 2 No 10 sets.... one earphone plays loud and clear the other is dead.... just a coincidence...?

Two other things I discovered....

One....
I took the microphone apart and applying the power source from the radio to the mic. I can hear clearly the sound coming from the metal mic set.... so that works.....

Two.....
The new relatively new old stock headset from the USA..... has a different black/red tracer cloth covering....with chamois on the earphone No 1 lollipop..... and the earphone works with the radio source.... BUT still only one earphone works...... AND I can trace/play the radio sound BUT by touching the post 2 green on the snatch plug instead of the common black no 3..... no response from the black post 3.....

Final questions.... are there any fuses inside the control box used on the wooden board for training... the control box has the 3 earphone connectors coming out the side and in the parts manual is referred to as .... control unit 3A MK II..

What's next Doctor...??

Bob C.

[Chris Suslowicz]

Originally Posted by Bob Carriere

Final questions.... are there any fuses inside the control box used on the wooden board for training... the control box has the 3 earphone connectors coming out the side and in the parts manual is referred to as .... control unit 3A MK II..

Bob C.

No, the only control units with a fuse inside are the No.1 family (1, 1A & 17). The No.4 does not have a fuse and has the 12V supply wired straight through. The fuse is present to protect the wiring harness against short circuiting pin 10 (+12V) to ground if _only_ a single control unit (1, 1A or 17) is in use and the control unit is switched to either the the IC or B position.

On the headset front, check the earpiece continuity with an ohmmeter, infinity means it's duff, remove and faulty ones (undo the nuts and disconnect the wiring then spring the headband clips to remove the earpiece from the headband), and replace the faulty one with a "known good" earpiece from another headset.

Chris.

[Bob Carriere]

...will disect the earphones tomorrow when the sun shines in the work room.....

Thanks for your help.....stay tuned.

Bob C.