148gtl made in china my rx/tx light is not working as well as transmit and recieve, any help would be great .what works is my channel display and meter lights also very fanted noise on speaker also hear that clicking noise when i keyup.
-
You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
148 gtl rx/tx led issue
- Thread starter kaos513
- Start date
check what Robb left you and see if you have 8 volts in and out of the band switch. should have 8 volts into the switch and then 8 volts out to aM, SSB modes. this is the switch for AM, LSB and USB. the in wire will have 8 volts constantly and as you turn to each other leg the voltage will move from AM, LSB and then USB.
China radio has a 9-Volt 3-terminal regulator. Schemo says "KIA7809". It's IC4, It's bolted to the side rail of the chassis, about midway front-to rear on the same side as the audio-power chip.
The leg towards the rear of the radio should have your full power-supply voltage. 13.8 or whatever your power supply is set for. The leg to the front of the radio should be 9 Volts DC. Center leg is ground.
If you don't have close to 9 Volts on the lead towards the front of the radio, the regulator may be bad.
On the other hand, if the side rail is hot right behind this chip, there is an overload to ground pulling down the output from the regulator.
Maybe.
73
The leg towards the rear of the radio should have your full power-supply voltage. 13.8 or whatever your power supply is set for. The leg to the front of the radio should be 9 Volts DC. Center leg is ground.
If you don't have close to 9 Volts on the lead towards the front of the radio, the regulator may be bad.
On the other hand, if the side rail is hot right behind this chip, there is an overload to ground pulling down the output from the regulator.
Maybe.
73
Fairchild is just one of many brands who sell that part.
If it passed on your transistor tester this leaves two possibilities.
1) Your tester is broken.
2) You did not interpret the test result correctly.
It's not a transistor. It's an integrated circuit with about 30 transistors, diodes and resistors on one silicon chip inside.
And it could be I'm wrong. The input and output pins are connected to a power transistor in the regulator's circuit. But not directly.
Gotta try that with one of my transistor testers. Could be that it will "fool" the tester and report a good transistor.
But it's not a transistor. It's an entire regulator circuit with a reference zener, error amplifier, temperature compensation, and overload-shutdown protection.
But the best test is to see if you get 9 Volts DC from the front-facing pin while the radio is powered up.
Still waiting to hear how that test turned out.
73
If it passed on your transistor tester this leaves two possibilities.
1) Your tester is broken.
2) You did not interpret the test result correctly.
It's not a transistor. It's an integrated circuit with about 30 transistors, diodes and resistors on one silicon chip inside.
And it could be I'm wrong. The input and output pins are connected to a power transistor in the regulator's circuit. But not directly.
Gotta try that with one of my transistor testers. Could be that it will "fool" the tester and report a good transistor.
But it's not a transistor. It's an entire regulator circuit with a reference zener, error amplifier, temperature compensation, and overload-shutdown protection.
But the best test is to see if you get 9 Volts DC from the front-facing pin while the radio is powered up.
Still waiting to hear how that test turned out.
73
while all of the suggestions are good ones, i'm wondering if his VCO coil is just out of adjustment.
this would cause the RX/TX light to stay green when the mic is keyed, and the radio would not have any receive.
kaos, is this what is happening, or is there no illumination on the RX/TX light at all?
LC
this would cause the RX/TX light to stay green when the mic is keyed, and the radio would not have any receive.
kaos, is this what is happening, or is there no illumination on the RX/TX light at all?
LC