GM300 and Pin 13

[tomsdad]

I've been playing with a GM300 and a Foxdigi with a view to setting up an APRS fill-in digpeater.

I had the 2 connect via a Meltxer Radio Engineering connector, basically it runs Pins 2 3 7 8 11 13 through to the Foxdigi (which uses the "standard" TT/Kantronics etc) pins in.

The radio powers the interface via pin 13 and all was going well until today I foolishly unplugged the Foxdigi to plug in a TT3 without powering off the radio:x

Looks like I shorted something as the radio is now dead - will not power up. Can it be repaired, is there a "fuse" or other limiting device that can be replaced, or is it for the bin?

Cheers, Steve VK2POO

[jackhackett]

You might have blown the ignition sense fuse which is a 2A picofuse near the accessory connector.
This fuse is connected to pin 10 and feeds voltage to it to power the radio, if you want the radio to be ignition switched you cut or blow the fuse and then feed switched voltage to pin 10.
If you shorted pin 10 by accident the fuse could blow causing the radio to not power up.

Of course there's the possibility that you blew something else.

[tomsdad]

You might have blown the ignition sense fuse which is a 2A picofuse near the accessory connector.
This fuse is connected to pin 10 and feeds voltage to it to power the radio, if you want the radio to be ignition switched you cut or blow the fuse and then feed switched voltage to pin 10.
If you shorted pin 10 by accident the fuse could blow causing the radio to not power up.

Of course there's the possibility that you blew something else.

feck!

I wonder if I can blame Dougal for this

Bit of a Father Ted fan myself;-)

Your Pico fuse sounds like the culprit and and a good place to start - especially as the radio expired without any noice or smoke.

Is it worth getting Mrs Doyle to make a cuppa tea and have a go at replacing it myself, or better of going to the local radio tech and paying him (translation - can a non tech locate and change the fuse?).

73 Steve VK2POO

[jackhackett]

Aw..... go on, go on, go on.....

The fuse is easy enough to find, it's on the logic board close to the accessory connector and looks like this:


The first thing to do would be to determine if it's actually bad. You can measure it with an ohmmeter (with no power applied to the radio), it should read pretty close to zero ohms.

Changing it requires basic soldering skills, the hardest part is removing the old one without damaging the circuit board. Probably the easiest way is remove the board from the radio, use a solder sucker or solder wick to remove the fuse, solder in the new one and trim off the leads, then put the radio back together.

An alternative to replacing the fuse would be to connect power to pin 10 of the accessory connector, if you've got a wire/pin to go in there that might be the easiest way to go.

[Jim202]

Aw..... go on, go on, go on.....

The fuse is easy enough to find, it's on the logic board close to the accessory connector and looks like this:


The first thing to do would be to determine if it's actually bad. You can measure it with an ohmmeter (with no power applied to the radio), it should read pretty close to zero ohms.

Changing it requires basic soldering skills, the hardest part is removing the old one without damaging the circuit board. Probably the easiest way is remove the board from the radio, use a solder sucker or solder wick to remove the fuse, solder in the new one and trim off the leads, then put the radio back together.

An alternative to replacing the fuse would be to connect power to pin 10 of the accessory connector, if you've got a wire/pin to go in there that might be the easiest way to go.

The fast and dirty way would be to just tack the new fuse across the old fuse. Looks like s***, but it gets the
job done without tearing the radio all apart.

Jim

[tomsdad]

Aw..... go on, go on, go on.....

The fuse is easy enough to find, it's on the logic board close to the accessory connector and looks like this:


The first thing to do would be to determine if it's actually bad. You can measure it with an ohmmeter (with no power applied to the radio), it should read pretty close to zero ohms.

Changing it requires basic soldering skills, the hardest part is removing the old one without damaging the circuit board. Probably the easiest way is remove the board from the radio, use a solder sucker or solder wick to remove the fuse, solder in the new one and trim off the leads, then put the radio back together.

An alternative to replacing the fuse would be to connect power to pin 10 of the accessory connector, if you've got a wire/pin to go in there that might be the easiest way to go.

Thanks Jack and Jim - my soldering skills are pretty basic and I do have some solder wick, but what I don't have is a replacement pico fuse - so I think it might be a trip the local radio shop.

Cheers!