AX144- No TX on AM/SSB no RX on AM but RX on SSB

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Min
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AX144- No TX on AM/SSB no RX on AM but RX on SSB

Post by Min »

hi all, I have a uniden ax144 which doesn`t transmit on AM or SSB.
It doesn`t receive on AM or SSB.
When I got this radio I was told the arial was hit by lightning and was connected to the radio.

Any ideas as to what might be wronge and how it can be fixed?

Thanks in advance
Min.
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Post by Min »

Hi all, this is another ax144 radio,It used to work fine but has been stored away for a few years. It transmits on am & ssb. Its receiving signal on the meter on am & ssb but no audio is comming through.
I`ve changed speaker, still nothing. I`ve check mike and its ok. It works on another ax144.
Its got me stuffed. Any ideas as to what might of happened and how I could fix it.
I`d really like to get this one fixed. This is my main radio for now. It has a channel expansion board which I have never seen before. It allows it to go up alot and to go down a ship load.All the channels are in order from 00 to 99. Also tells you which frequency your on when you press the mic.
eg:display shows 66. When you press the mic you`ll see 27. 27.665mhz.

Would be a shame to not fix it.

Please someone help me or give ideas as to what might be wronge.

Thanks in advance.
nomadradio
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Post by nomadradio »

Hmmm. This is the point in the troubleshooting process where I grab for a 'scope probe. For the moment, I'll just guess that you don't have one handy.

Or an external speaker. The internal speaker is switched off when an external one is plugged in. If that switch contact in the external jack goes bad, the internal speaker won't work. But an external speaker will.

First thing to find out is if you can hear a "squelch thump".

Turn the volume control full up. Turn the squelch all the way to the left. Now spin the squelch knob to the right. You should hear a faint, low-pitched "thump" from the speaker. Gotta spin it fairly fast to get this from it.

If you can hear the "thump", this means that the audio power chip and other parts on it are at least partly alive.

If you can't hear the thump, it's time to find out what tools and instruments you have on hand.

As for the "lightning" radio, there is not much hope for that one. Only one way to get that one going again. And that requires removing numerous parts and testing them one at a time.

Unless you have a good tester for capacitors, coils, transistors and diodes, this is a steep uphill climb.

Even with the tools, and spares for ALL the parts inside, this kind of job will prove to be a long haul, before everything is right again.

Repairing a lightning-damaged radio is sorta the radio-repair equivalent of the Rubik's Cube puzzle.

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Post by Min »

hi nomadradio, your right i dont have a scope.
I just tryed turning the volume all the way up and turning the squelch slow and fairly fast and theres not thump of any sort. All i can hear is faint static. Throught the nomal speaker or the extension speaker.
The extension speaker works as i am now partly deaf due to trying in on the pa.
As for what tools i have, pretty much nothing. A soldering iron, multimeter and screw drivers. Also have a scanner and a frequency conter.

I have changed the Volume/Squelch switch with a good working one and its still the same.

I have just read a post that maybe there could be a dry soldier joint on the uPC1242. I have re soldiered all the points and still the same.
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Post by Min »

I have just changed UPC1242H. When I used a different radio I could here myself talking but when I didn`t talk I still had to put my ear to the speaker to hear the static. I could hear myself talk load and clear though.
After the radio being on for about 30 seconds its got no receive again.

Any ideas????
Please help me.
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Min
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Post by Min »

i have just went over all the soldier points near the upc1242h and now when i transmit with my backup radio i can hear myself but only if i put my ear to the speaker and the volume all the way up.

Any ideas???
help me please.
nomadradio
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Post by nomadradio »

Wait a minute, are you saying you can get receiver audio from the external speaker?

Or JUST the PA audio?

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Post by Min »

I did get sound from the speaker, for at least 30 seconds. Then it died again. I can still hear if i put my ear to the speaker though.
I doesn`t work with the ext speaker jack.
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