THIS TRANSCEIVER HAS AN ISSUE(S)
It is very important that those interested in this transceiver to read EVERYTHING in this detailed description so that you can gain an idea of what needs to be done!
Looking on the bright side, the fault is easier to "track down" than an intermittent (the unit is stone cold dead!)
Perhaps of more interest is the complete front panel assembly, easy to remove and replace an existing TX4000 front panel that is either damaged or the screen has seen better times or even just for the pull off knobs!
HISTORY:
In a previous life I was heavily involved in professional communications (Maritime) and on a personal level, Amateur radio (ex VK2DWF and now relinquished for some years) so of course I collected radio equipment and to a certain extent still do "just for fun" but these days I am "over it all" and have been working through a box of radio equipment sitting in the storage units.
GME Electrophone were ground breakers in their day, Australian designed and manufactured UHF radio equipment (right here in Sydney) and what's more, considered to be very reliable and good quality equipment.
The TX4000 was well known by communication enthusiasts and travellers, and this equipment from GME wasn't just a "one hit wonder" with the later TX models (4200, 4400 etc) continuing the companies reputation for very good quality equipment.
Built in (preset) selcall function along with all the usual features expected of a consumer grade, analog UHF CB transceiver.
If you are looking for a transceiver that you can power up and start talking immediately to your fellow "crazies" (or as many are on UHF CB, they often just utter strange gurgling sounds or hurl profanities at each other) this equipment is NOT FOR YOU!
If however you have "some" technical abilities in relation to radio equipment (fault diagnosis, some test equipment and soldering skills - particularly when dealing with SMD technology), this may be a "fun thing" to play around with.
From my own point of view, this was always going to be a "part out" piece of gear, that front panel assembly in particular is very easy to remove and disconnect the connectors and transfer to another TX4000 - trouble was I did not ever get another TX4000 that was not working!
I had a few TX4000's back in the old days (around the 1990's) and this was the only one that had an issue. All of the fully functioning TX4000's have now found new "shacks" or 4WD's to live in.
Please read on for the details of this GME Electrophone TX4000 mobile transceiver ...
GME ELECTROPHONE (AUSTRALIA) - COMMUNICATIONS TRANSCEIVER
Designed & made in Australia
Model: TX4000
Analog FM UHF Transceiver
Frequency range: UHF CD band 476 - 477Mhz
RF power output: 5W
Internal speaker fitted
Basic front panel push button & rotary controls i.e Volume, Channel Up & Down, Four Function buttons (Scan, Squelch level etc)
LCD display
PL259 Antenna connector on a short tail
External Speaker connector
DC (nominally 13.8V) is supplied directly into the transceiver (no DC plug/socket)
ITEMS NOT SUPPLIED:
A microphone is NOT supplied but is available as a separate item HERE
Mounting bracket and thumb screws are NOT supplied
DIMENSIONS:
175mm wide x 180mm depth x 55mm height
WEIGHT:
1.25Kg
COSMETIC CONDITION:
USED
CLEAN
NO physical damage to the thick steel (two part) main body or the front panel
NO knobs or buttons missing
Display screen is clean, no damage is apparent and unscratched
Inside the unit is very clean on both sides of the main PCB
DC lead is just a short tail, bare wire terminations (there is no fuse/holder fitted)
Both the top and bottom steel sections of the outer body have normal scratching and marks, understandable in a harsh mobile environment.
TESTING:
This is the part that really matters!
I only had a 12V supply at hand for testing and at a low current capability but at least it enabled me to make some basic tests.
Same goes for an antenna, just a simple 'whip' antenna used for testing, not that it really mattered ... see below
Power ON (rotate the front panel knob) and the NOTHING CHANGES!
Dead as a parrot in the pet shop (Monty Python reference)
I have a current meter inline with the supply and it does not budge from zero - no current is being drawn at all.
I checked the voltage right at the PCB and yes, the supply is present.
At this point I am not about to go on a fault diagnosis trip, that will be up to the new owner (or just part it out - I do know for a fact that the front panel works fine as some time ago I did an exchange with another TX4000 and there were no problems at all - the fault lies on the main PCB.
Some hurdles to overcome here ....
As far as I can determine, NO schematics are available. I don't have them in my service library and online didn't help at all either.
The construction of the TX4000 main board is a double sided board with a hybrid of thru hole components and SMD components. So you will need to deal with those tiny little chip components used in SMD architecture.
I like the multiple connectors used to connect the front panel assembly to the main board, this makes for removal of the front panel a snap - easy as.
Those connectors are keyed so you cannot accidently reinsert them the wrong way around!
I looked around the main PCB for an onboard fuse or fusible link but found none.
No obvious signs of component stress (cooked looking or even just heat related "burning")
I do notice two carbon resistors and a small signal diode added on the underside (SMD side) which look to be a modification made some time in the past. I do not think these are the cause of the no power issue - life would have been a lot easier with a schematic!
So, it is here that my investigation ends ....
NO POWER NO CURRENT DRAWN AT ALL and of course the display is completely dead, as is the loudspeaker (not even a "click" at power on)
So there you have it, a nice "technically advanced" (for the 1990's) UHF transceiver from GME Electrophone, an Australian iconic communications equipment manufacturer.
It has been sitting in my box of communications equipment for years, now it wants to give another TX4000 a new lease of life or better still, be bought back to life itself!
