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 Post subject: Gonset Communicator II mic
PostPosted: May Sun 19, 2019 11:03 pm 
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Joined: Jan Tue 29, 2019 11:18 am
Posts: 4
Hello folks
I have received a Gonset 6m transceiver and I get no audio through the mic
I have tried a 900ohm carbon mic and also a cb dynsmamic mic with no success
I wired it ground to sleeve and mic to ring leaving tip with no connection

I guess the is no PTT as i have seen no wires connected inside on the back of the mic connector

Any Idea? How does the Pa work? Do I have to switch to Transmit mode to get sound from the speaker?


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Last edited by EA3IAV on May Mon 20, 2019 8:22 am, edited 1 time in total.
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 Post subject: Re: Gonset Communicator II mic
PostPosted: May Mon 20, 2019 1:44 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 3635
Location: Monterey California USA
Some Communicator II's have push-to-talk, some do not. Probably most do not. In which case you have to place the lever switch into transmit, and also push the PTT button on a modern microphone. A nuisance.

There is a slide switch on the back of the transmitter for carbon or hi-impedance microphone. That has to be in the correct position and the mic gain control set properly. 900 Ohms sounds strange for a carbon element, maybe it will be OK.

I don't understand your question about PA. The speaker is not in use while in transmit or in the PA mode. You can plug in an external speaker to that phono jack on the rear apron of the transmitter and use the "PA" function (Public Address, not "Power Amplifier) to test your microphone and wiring, which is done by NOT turning the transmitter filament switch on. But you will still have to adjust the modulation level control when actually transmitting.

Hopefully you have already overhauled this radio. The perforated top of the cabinet lets lots of dust and debris in and it packs up the tank coil and the tank components over many years. Washing it all out with residue-free electronic cleaner is usually necessary.

_________________
WB6NVH
California Highway Patrol Radio
Bell System Mobile Telephone History
http://www.wb6nvh.com


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 Post subject: Re: Gonset Communicator II mic
PostPosted: May Mon 20, 2019 5:29 am 
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Joined: Nov Sat 07, 2009 11:37 pm
Posts: 2116
Location: Sayreville, NJ 08872
A carbon mike with a 900 ohm impedance sounds very high. How do you know it's 900 ohms? Most carbon mikes have an impedance in the range of 30 to 50 ohms.

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Pete, WA2CWA - "A cluttered desk is a sign of genius"
http://www.classicradiomanuals.com


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 Post subject: Re: Gonset Communicator II mic
PostPosted: May Mon 20, 2019 8:03 am 
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Joined: Jan Tue 29, 2019 11:18 am
Posts: 4
I was told that the mic was carbon type. It comes from an army handset made by IRET and present on some radios like the RUP-15

Image
I have seen that this carbon mics need an external power source. I guess this is already accomplished inside the Gonset by switching it to Carbon possition.
Instead, I may try to use a Crystal mic I I find one!
Do you think this would work? http://vi.raptor.ebaydesc.com/ws/eBayIS ... spheader=1

Yes I have been replacing some filter caps, resistors and tube capacitors. This is what I enjoy the most ;)
I am having problems with the squelch, not working at all. I guess I have to play with the resistor on the side of its potentiontiometer.

Thank you for your help


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 Post subject: Re: Gonset Communicator II mic
PostPosted: Jun Wed 19, 2019 6:14 pm 
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Joined: Jan Tue 29, 2019 11:18 am
Posts: 4
I have teplaced every tube on the transmit section except the 6v6 (I didn’t find it yet) and the magic eye
Now there output is 5w and after playing eith some mics I managed to get some sound out of the radio using a clansman rt320 handheld mic capsule.
I have stumbled upon a new problem. Seems like after replacing all tubes now the magic eye is almost gone. It is barely visible. It was quite bright before changing the rest of the tubes. I guess that there is more drain now. Id there a eay to give more light to it?

http://www.radiomanual.info/schemi/Surp ... 49_sch.pdf


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 Post subject: Re: Gonset Communicator II mic
PostPosted: Jun Wed 19, 2019 7:02 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 3635
Location: Monterey California USA
Did you check the voltage at the eye tube? Supposed to be around 250V at point II. There is a 1.2 Meg resistor across the eye tube socket that in most designs is usually hidden inside the socket cap, but I don't know where it is in Gonsets. They drift up in value or open.

You may have noticed that there is a safety hazard with these radios, in that the only ground return is via the antenna cabling's shields when the chassis sections are out of the cabinet.

At the moment I suspect you have a wiring error, honestly. An eye tube that was bright before isn't suddenly going to be dim after changing some capacitors and tubes. I do not know why you changed all the tubes, which is going to be a waste of money. I suppose because you do not have a tube tester? Surely all the tubes didn't need replacement. If you have audio and the 6V6 isn't a blue flashbulb, it is OK for the time being.

_________________
WB6NVH
California Highway Patrol Radio
Bell System Mobile Telephone History
http://www.wb6nvh.com


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 Post subject: Re: Gonset Communicator II mic
PostPosted: Jun Wed 19, 2019 7:44 pm 
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Joined: Jan Tue 29, 2019 11:18 am
Posts: 4
Hello! I took all tubes because at a ham fest they were like 8$ and I have no way to test tubes. I tested every resistor and cap. Inside the magic’s eye socket there is a 1 M resistir that was fine. Changing tubes was my next step.
I have tested voltage on the magics eye socket here it is what I got


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 Post subject: Re: Gonset Communicator II mic
PostPosted: Jun Sat 22, 2019 7:51 am 
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Joined: Nov Mon 02, 2009 7:01 am
Posts: 3491
Location: Lincoln City, OR
Greetings to EA3IAV and the Forum:

If you measured the eye tube voltages with the tube out of its socket as implied in your photo, the measurements don't really mean anything. You have to measure tube voltages with the tube in the circuit.

With all power removed, you can use an ohm meter to locate where all the wires in the eye tube wire harness appear and measure the voltages there... except that you will not be able to measure on the other side of the 1 Meg resistor.

Normally, if the eye tube was bright and now is dim, the B+ is being pulled low for some reason.... be careful to operate the radio for only short periods until you find the cause or serious damage may result.

The squelch circuit works by taking a sample of the discriminator audio, running it through a high-pass filter and rectifying the result. The resulting bias is used to cut off a tube in the receiver audio chain. If your receiver is running continuously un-squelched and the control has no effect, by all means, check the resistances in the circuit, but you will probably need a scope to find the problem.

Be sure that the replacement tubes you installed are actually good.... it is possible to replace old working tubes with "new" tubes that are in worse shape than the old ones. Best to substitute tubes one at a time and observe the results rather than in wholesale lots.

Good Luck,

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Jim T.
KB6GM


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