GME TX472D receiving, not sending..

[happykid55]

Hi sorry if this has been covered but i have searched..
Ive had a GME TX472D in the shed for a while and iv'e recently put in the rangie,
I re-wired the antenna, but the radio will not send a clear signal, it can receive loud and clear but when i try to transmit, it makes a static noise when I press the button on the microphone that can be heard on another radio but no voice/sound comes through, then when the button is released the static is heard again. Also the "TX" light appears on the screen when the button is held in.
Could this still be a matter of a bad antenna, faulty microphone? or just a radio thats had it?

Thanks for any help.

[PhilipA]

My guess would be microphone.
have you tried whacking it on a hard surface a few times?

Seeing people at the receiving end hear a signal. strength? and the TX light comes on it would suggest microphone.
Perhaps try another mic if you can.
Regards Philip A

[happykid55]

Tried whacking it, and more of the same.
I've been looking for another mic but I can't seem to find one,
Anybody with a spare I'm willing to pay for it.

[nigelbuilding1984]

hi the same thing happend with mine it was a bad earth on my ariel so i ran a seperate earth strap at the mounting base of the areial now it works clear as day

[happykid55]

Just called GME and they dont make any microphones to fit them anymore, not really a surprise there.
Tried the ariel with a separate earth connection and no luck.. :(
Seriously considering replacing the whole unit which is a bit of a shame.

[PhilipA]

Just for the record, the earth on the antenna is to complete the coax earth circuit to isolate the inner wire from RFI.
It should have no effect on transmission if say the engine was stopped and just maybe cause a heap of static with the engine going.
I think that you may have fixed a poor connection of the actual inner wire at the same time.
I currently do not have the antenna end of my coax earthed as it runs up my B pillar to the console , away from any RFI and I didn't want to break the paint in the gutter.
My 18 year old Uniden transmits perfectly.
Most if not all mobile phone screen antennas are not earthed.

BTW HappyKid? You should be able to get a tech to connect your plug to a new Mic. OR In many cases the twisting of the cable by picking it up etc has just broken a wire where it goes into the mic or at the plug end. Get out the little screwdriver and have a look.
Regards Philip A

[happykid55]

thanks Phil,
I pulled off the back of the mic and all the wires seem to be in the right place in good working order unfortunately.
i wonder if the wires on the inside are generic, and a different mic could just be connected up on the inside to the old cable?

[Sprint]

what plug does it have? 4 or 5 pin round?

[PhilipA]

I pulled off the back of the mic and all the wires seem to be in the right place in good working order unfortunately.

Happykid, we got a bit ahead of ourselves here.
AFAIR , I asked that you advise what the person receiving reported as the signal strength.
It may well be that the amplifier is crook, or the antenna lead is broken.
Maybe go to a specialist shop for them to check it.
I cannot see your location from this pane, but if in Sydney there is a shop at Roseville AFAIR.
Regards Philip A

[ahumbert]

Phillip

Any chance that you can recall the name of the shop as I have a similar problem and haven't been able to locate any repair shops on the north shore as yet.

Allan

[PhilipA]

There doesn't seem to be any record of the communications shop any more. Ah well, things change.
Why not call GME and ask them who they recommend as a service agent?
Quote from Explore Oz.


Try GME Electraphone in Gladesville, there number is (02) 9844 6666 or go to there web site at Welcome | GME (http://www.gme.net.au) by the way i have no affiliation with GME, i just like their products, cheers, Dave.

I found this source of microphones for a TX472S which is probably like a D with a 6 pin microphone.
http://www.who-sells-it.com/images/catalogs/3405/pdf_16879.pdf

While I know nothing about fixing electronic problems , I could test your unit and have a look at the antenna by receiving with mine, if you feel like driving to Avoca Beach.
Regards Philip A

[happykid55]

Happykid, we got a bit ahead of ourselves here.
AFAIR , I asked that you advise what the person receiving reported as the signal strength.
It may well be that the amplifier is crook, or the antenna lead is broken.
Maybe go to a specialist shop for them to check it.
I cannot see your location from this pane, but if in Sydney there is a shop at Roseville AFAIR.
Regards Philip A

I tested the signal only by using a handheld UHF only about 30m away.
Im not sure what you mean by signal strength of the person receiving because all they receive is a static noise when the mic button is released. however on my car unit (the problem one) the signal is loud and clear when receiving from the hand held at that distance. I have used both a largish fiberglass (i think) antenna and a small wire one and the symptoms were the same with each.
Im located near parramatta, I called that GME gladesville office to ask about a replacement mic and they were helpful so ill try again and ask about where a specialist shop might be closer to me.
If their diagnosis is a bad mic then ill replace it.
Thanks for the help so far, and if you think the test that i conducted wasn't sufficient then what would be a better way to do it?

[Basil135]

A quick & simple test is to check your aerial connections with a multi meter.

Take the plug out of the back of the radio, and check between the outside & the centre pin. It should show that there is no connection between the two.

If there is any sort of connection, you have a wiring fault in the antenna.

Next, check for breaks in the cable with the multi meter. Centre to centre should show very little resistance.

At the range you are testing, it is possible that a signal will get into your radio, but if the antenna wiring is faulty, then you wont get one out.

[PhilipA]

Most in-car units AFAIK have a signal strength meter which is a number of climbing bars, just like the one on your mobile Phone. My Uniden does.

If the person receiving reasonably close to you is showing a good signal strength but no audio, then your microphone is probably stuffed.

If the person receiving shows a weak signal strength, then your antenna is not connected properly, your transmitter amplifier is stuffed , or there is something else wrong.
Regards Philip A

[John W]

My radio was doing something like yours. I tracked the fault to being a poor earth (12v) connection to the radio. Obviously for reception the current draw is a lot less than transmission current so it was only during transmission that there was a problem. These partial faults are always a pain in the backside to sort, would have been easier for me if had died altogether.

[Sprint]

what microphone connector does it have?