| Author |
Message |
    
Spike
| | Posted on Friday, December 13, 2002 - 7:33 pm: | 
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Hi! I have a Genral Electric 3-4804D mobile with the pll02a. The radio works in every way, except it does not transmit at all.
The receive is fine, and if I key the mic and whistle, the led glows and varies with modulation, but the meter does't move a bit.
It shows no wattage on the wattmeter, and another radio set up doesn't receive any signal from this rig.
I am no tech at all, but if everything else works, I'm hoping it's something simple.
Any help would be greatly appreciated!
-Spike |
Spike
| | Posted on Sunday, December 15, 2002 - 4:02 pm: |
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Anyone? |
2600
| | Posted on Sunday, December 15, 2002 - 9:30 pm: |
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I don't remember the callout numbers, but this radio has a 10.695 MHz crystal that would lay down and refuse to run, sometimes. The frequency is marked on the crystal. It's at one end of a single-inline 9-pin chip marked "C3001". The chip is just a TA7310 with Cybernet's house number printed on it. The simple test for this is a nearby radio on the same channel. Plug a coax jumper into the 'monitor' radio, and unscrew the shell from the plug on the other end. The tip of this jumper is now a 'sniffing' antenna. If you hear the carrier from the GE when you key it, the problem is NOT with this crystal or chip. If it's completely dead with this test, you can check the 10.695 crystal on a 'scope. Touching the probe tip to one of the crystal pads on the PC board will sometimes "kick" it into running again. If this brings back normal output power, replacing BOTH the chip and crystal usually fixes it.
If you DO hear the carrier from the GE, your problem is DOWNSTREAM from the crystal/chip, like the driver, final or spike diode.
73 |
Spike
| | Posted on Monday, December 16, 2002 - 5:27 pm: |
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Thanks 2600! I'll give it a try.
Thanks again,
-Spike |
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