Hi Guys, could really do with a bit of help on this one, I have just bought a magnum 257, it Transmits fine (power wise) and receives no problem, but I can't get any audio output, Audio output IC seems fine, so I suspected mic/plug/wire, what I actually found was the mic socket has 13.8v on pin 3, which I thought was the Transmit pin, but it has no voltage on pin 6... which is where it should be....now from what info I can find on the mic wiring of the 257 it should have voltage on pin 6..please correct me if I am wrong..unless magnums have a new mic wiring set up (the radio is the newest version) ...I know the microphones on these radios work like the old k40 speech processors where they charge a small capacitor, is it safe to assume the mic socket is wired incorrectly and put the voltage to pin 6? any help greatly appreciated.
Hello.I have a similar situation on a Magnum 257 HP operating on SSB (AM and FM works fine). If i Transmit it works fine, but when i release the Mic button (after TX), in the bottom side were the RX level should be, it appear somth like a signal level 3 to 5 (constant and continous), but i can't get any reception at all. Only if i turn the TX power level to MAXand i transmit, then it goes back to reception, but not every time. Somtime after TX i need to push the mic button 2-3 times to make it recive somthing, but this wors only if the power level is over 60-70% an i repeat, only on SSB.Can i get some help with this issue?
You will need a full service manual to trace the pin layout, As you have detected 13,8 vdc+ it is not wise to use the pinout bridging method to find the RX pins..if you should choose to do this, use a 21watt auto lamp in series with the bridge. This will help save you from a "big smoker".If the set still has high value
i would take it to a raido tech. The comment from Winkster is valid.....some companies fall very short with after sales service.
GOOD LUCK
Theres a tiny and i mean tiny surface mount resistor on the back of the centre pin which blows causing this fault
The magnum 257 has a power mike. pull it apart and you will see a pot to adjust.They are usually turned low from the factory and need setting to your specs. People who have done it have said all ok and very happy.
I have a 257, I found the mic that comes with it very poor audio output, so I opted for a power mic a astatic which works fine
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I had almost the same problem being that the radio was still new I sent it back to magnum. Let me tell you I still haven't gotten the radio back it's been a month. Magnum sucks I wouldn't buy **** from them ever again. Spread the word Stay away from magnum products!
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