GP300 VHF Wont Stop Transmitting.

Satelite · Post by **Satelite** » Sat Feb 24, 2007 10:26 am

Hello
I have a GP300 VHF 2ch 146/174 split 5 watt portable.
When you first turn it on it recieves fine but when you key it up to talk back it will key up but wont unkey after you let off of the PTT.
Took it out of the case thinking the rubber actuator might be the trouble = Nope.
Then powered it up out of the case and pressed the PTT button and let off but still continued transmitting.
Unsoldered the PTT switch and soldered in a brand new one ans still wouldnt stop transmitting after you unkeyed.
Tried programming in a known good code plug with the exact model number and split ect = Still wont unkey.
Once it is keyed up and transmits the only way to stop it is to turn the radio off then back on again and it will recieve fine until you key it up then it keeps transmitting until radio is powered down.
Anybody have any sugestions besides a big hammer which im close to considering.

Thank you
Satelite

fogster · Post by **fogster** » Sat Feb 24, 2007 11:02 am

It sounds like you've tried more than I have, but I'm still curious if we might be having the same issue...

When it gets 'stuck,' have you ever tried pounding the PTT-side of the radio against your hand? Not a pretty solution, but it unsticks PTT for me.

I'm just curious because I'd assumed mine was a simple issue of something sticking, whereas you've done a lot more prodding.

(FWIW, mine's an 8-channel UHF.)

Will · Post by **Will** » Sat Feb 24, 2007 8:23 pm

Have you tested the GP300 into a known good dummy load and cable with the proper adapter.

Sometimes a bad antenna or the wrong range antenna will reflect lots of RF back into the radio.

Bruce1807 · Post by **Bruce1807** » Sun Feb 25, 2007 8:42 am

could have crap in the headset adaptor.

Satelite · Post by **Satelite** » Thu Mar 01, 2007 4:27 pm

Update
Yep tried beating the H out of it - Didnt stop txing but i felt better>

Sprayed electronic cleaner into the mike/speaker jacks and air sprayed into the jacks to dry out = no luck= Went back to beating it up >Felt Better

Also as sugested put it on a 50 ohm dummy load and it didnt make any diference = You qeussed it/ I feel better again after beating it up some more.

Im going to use it for parts now that i got a hold of a GP300 16ch with scan and DTMF = Now if i just had a phone patch but it ocupies my time amusing me playing with it.

But i would like to thank everyone for the help.
PS = I dont have to beat the wife = I got a P110 NOW

Satelite

Andreas · Post by **Andreas** » Fri Mar 02, 2007 12:23 am

Remove the power amp from the mainboard and try it again.If the problem is still there it looks like a bad CPU.

Andreas

Satelite · Post by **Satelite** » Sun Mar 04, 2007 2:00 pm

Hello
Tried as sugested = Removing the power amp and replaced with another and it did the same =Still wont stop the tx after being keyed up.
Im going to try for kicks and giggles turning down the wattage from 5 watts to 1 watt and see if that helps .
Thinking Will might have the answer being desense in the radio some how.
Satelite

k2hz · Post by **k2hz** » Sun Mar 04, 2007 4:21 pm

Have you carefully inspected the mic jack and circuit boards for any sign of water damage or other contamination??

It is possible that something is providing a leakage path to the PTT line that is not enough to key it but will hold it on after it is keyed.

I have seen this symptom in many kinds of radios with corrosion or contamination bridging pins on the mic jack or a damaged area on the circuit boards affecting the PTT line.

Andreas · Post by **Andreas** » Sun Mar 04, 2007 10:13 pm

Don´t put the new power amp on it!Try without!

Andreas

richb · Post by **richb** » Tue Mar 13, 2007 6:01 pm

also you couldlook at the dptt line it could be bad. also the unit could be spuring check it with a spec analizer if one is avaible.
this could point you in the right direction.

richb