Gme Tx4000

[kerinvalecomaudio]

I have a tx 4000 that receives ok but wont transmitt .The output stage is ok ,it seems to be a faulty vco as the ct601 has been replaced before with a new 2-6pf cap and it has fixed the problem previously .I replaced it again and it has fixed it again but it doesnt seem to fix the problem permantly.When this problem shows up the voltages on the pins to the vco pcb are all ok but no uhf output to the final stages and the frequency coming out of the vco pcb are 461mhz on rx which seem ok as its working but on tx the output is around 488mhz which isn't stable and seems too high .When tuning the ct601 also the tx voltage isn't near the rx voltage .ie you set the vco for 1.5 volts (tp1) on rx and the receiver works a1 and then check the voltage on tx and it could be at 0 or 4volts and no tx . Set the voltage on tx for 1.5v and it is very touchy to get the tx to transmitt and when check on rx the voltage is different again.Has anyone come across this problem .Thanks Ian Wells kerincom@pacific.net.au

[kerinvalecomaudio]

Hi guys .Just a quick add on.Contacted gme and found that some of the earlier tx4000 had faults with the vco (hair line fracktures in the vco board caps) and a new dual pot vco (one cap for tx and one for the rx) is available around $30.00 which we ordered in and installed (take care of removal and installation of the boards as the pins have to be clear of any solder before lifting the board of the motherboard so no damage to the pcb tracks) and we reset the vco voltage and a1 it worked perfectly continously for a week and should still be going well today.The client which was a repeater organisation which had sent this radio back and forward to a local gme agent and last time he had been charged $180 and still no fixing the problem compared thats where they bought it from,so you understand they were not very happy with the agent .I am sorry to hear there are communication businesses out there that will damage the image of one of our biggest radio makers just to make a quick buck.Thanks ian