gme gx548 vhf Issue
Submitted by brown364 on Sun, 2017-02-12 23:44
Having trouble with this unit blowing its fuse as soon as handset button is depressed and was keen to know if anyone has had a similar issue. Was thinking of replacing handset if that will solve it or any other advice appreciated. I did take it to a boat mechanic in balcatta (big one) years ago and they suggested to my wife when she picked it up after servicing ,to just use a bigger fuse
Image Upload:
Taffy
Posts: 183
Date Joined: 04/11/10
What size fuse
What size fues are you using ??? most radios draw around 6amps on tx at 25watt (classed as HI power lol)
so a 7.5 amp fuse will work just fine
JohnSorrell
Posts: 137
Date Joined: 28/07/09
Is the unit receiving OK?Have
Is the unit receiving OK?
Have you tried testing the unit in LO power mode (1watt) to see if the fuse blows when you TX?
If OK, then just install a bigger fuse (7.5-10A)...
If not, then it could be a bad antenna connection, water in your antenna or a fault in the rf transceiver.
Gone Fishing...
sunshine
Posts: 2555
Date Joined: 03/03/09
High power isn't 25 watts it is 5 watts
And you should never put an over amp fuse to stop the correct one from blowing....it blows because there is a short circuit ....fix the short !
looking at the vintage of the radio replace it....your life is worth a lot more than a replacement
Taffy
Posts: 183
Date Joined: 04/11/10
Hi Power Is 25watt
Hi Power is 25watt for VHF (Sunshine) maybe your refering to a handheld lol
The Originol fuse for that radio is 6amp
marrisy
Posts: 198
Date Joined: 08/09/11
Does the fuse only service
Does the fuse only service the tx, or is there any other electrical gear after the fuse. I had a similar issue, discovered the gps and sonar were also drawing through the same fuse. And as Sunshine says, if its as old as it looks, what is your life (or kids/friends) worth? Marrisy.
meglodon
Posts: 5981
Date Joined: 17/06/10
Check all connections
Just my two pennies worth I'd start by checking all of the connections to the radio, antenna, speakers Arial etc.
All of them must be very clean, no corrosion or staining etc.
You haven't stated if you can receive on the radio. if you can receive and it only blows the 1 amp fuse when you try to transmit then to me something is shorting in the hand piece as this is when the radio is going to draw the power.
Try a test transmittion on low power setting (if there is one) and then on the high power setting (if there is one).
If the fuse blows at both settings remove the handset check the pin connections in the radio and the hand set. Dismantle the hand set and check the inside connections at the transmit button for contamination by corrosion water and such.
With the Ariel there should be a very small hole at the base of the winding area of the Ariel to let out any ingress of water check this also to ensure it is clear (if in fact it has one)
sunshine
Posts: 2555
Date Joined: 03/03/09
Apologies 25 watts and draws 4.5 amps
At full power so a 5 or 6 amp fuse should be installed. I stand by my original comments on vintage of the unit, better to be safe and update now rather than have it fail when you really need it.
JohnSorrell
Posts: 137
Date Joined: 28/07/09
Hahaha!... Why throw away
Hahaha!... Why throw away $250-400 on a perfectly good VHF transceiver (probably), just because it looks old... open it up and youll find the PCBs looking like new... And so what it blows fuses (probably due to poor installation/terminations/insufficient fuse ratings)
Replace it without proper troubleshooting and youll probably have the same old problem, with the bonus of having a lighter wallet and a working VHF paper weight.
ALSO FYI.... the hand mic has low power circuitry... it has a micro switch to trigger the control IC's to enable the TX circuit and microphone amplifier. Therefore the handset itself has nothing to do with this unit blowing fuses. The fact the fuse is blowing shows the mic handset is working and enabling the tx circuit. Also... The wires inside the microphone cord cable would actually melt if 6Amps@12V passed through them.
Also FUSE rating as per the manual is 10AMPS. (not exact model but close enough, since only difference is the num keys) ..
https://www.gme.net.au/media/1390857/gx558_im_web.pdf
Gone Fishing...
brown364
Posts: 247
Date Joined: 25/08/15
Thanks peeps
I will certainly run through the trouble shooting items and see what I can find. And John , i am with you in the don't through away dept! If I can't work it out with the pointers you fellas have given then I will get it looked at or replaced .At the moment the moment its faulty, not broke!
thanks once again and get out amounts it!
364
JohnSorrell
Posts: 137
Date Joined: 28/07/09
Just a FYI... fuse ratings
Just a FYI... fuse ratings never match the manufacturers power consumption ratings.. For example... this VHF has a max rating of 4.5A during TX at 25W.... so why does it have a 10A fuse rating?! For anyone that has ever installed a winch motor you will question why a 50A motor requires a 100A fuse... I can explain but ... no point.. install a 10A fuse and if you do get a short circuit, as long as you are not using speaker wire to power your radio, the fuse will blow and the cable wont set on fire.
Gone Fishing...
hooty
Posts: 198
Date Joined: 25/05/10
If it's like the newer
If it's like the newer versions unplug the mike and try another one. Common to get water in the mikes, which then blow fuses.
sunshine
Posts: 2555
Date Joined: 03/03/09
Accepting the risk of being shouted down, it is even
Was a ham radio operator for many many years (VK6XI) and built solid state supplies and amps both valve and transistor ......so whilst I am getting old I have not forgotten everything I learned. To draw sufficient amperage to blow the fuse (unless the fuse was old and corroded and depending upon type) then unless there is a dead short before the finals, the transistor providing the transmitting power, then bluntly the cost of a technician to diagnose and fix the problem is highly likely to exceed the cost of a replacement. Simple financial reality of this throw away society. Got rid of most of my test equipment when I relinquished my ham licence or I would offer to try and diagnose the issue.
Dale
Posts: 7930
Date Joined: 13/09/05
"Just because you are a Character, Doesn't mean you have Character."
Mr Wolf
JohnSorrell
Posts: 137
Date Joined: 28/07/09
All good mate .... I also
All good mate .... I also hate the fact that the cost of labour to repair electronics usually turns out more expensive than buying a new unit.. But you have to admit, the cost of the electronics has seriously dropped.. so its really not that bad for the customers.. just sucks for the repair techies and engineers that lose out on work. Also their own fault for having such freakin high wages.
But I can't talk... I have worked as a marine electronics designer / engineer for the last 11 years and when it comes to repairing radios, I feel sorry for the customers that dont request a quote prior to having the work done... ALTHOUGH!!! I did fix an old Simrad NX45 unit a week ago in less than an hour, and the cost to replace would have been over $2.5k so the customer saved not only his GPS spots, but also about $2k if he was to replace with a similar unit.
Also, now that I think about it, if this radio had a sufficient fuse (which we dont know) this whole time... if there was water or a tiny strant of the coax sheild shorting the antenna connector, the fuse will pop when you transmit, then if you don't fix the problem, it will blow the tx amps / transistors. And if thats the case, then no point repairing...
Gone Fishing...
meglodon
Posts: 5981
Date Joined: 17/06/10
You are right on the money
We are a throw away society and as you have said to try to get the radio repaired will cost you an arm and a leg.
I tried to get a GME radio looked at to find the fault and the guy at the counter said "don't even give it a thought" as the cost will be unbelievable.
What has the world come to.