President Grant DX

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booger351
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President Grant DX

Post by booger351 »

Radio Make. President
Radio Model. Grant
PCB number. pc-999 ac
PLL number. mb8719

When the radio is keyed, the recieve indicator does not go out while the tx indicator lights up, and the radio shows no power output on a external meter.
If the roger beep button is pushed in the recieve light blinks when the radio is keyed up and it shows power output on the meter, but sounds like a helicopter, lol.
I have checked the voltages on tr35, and tr36, and everything seems ok there.
I believe it to be a problem with ic4, but i'm not sure.
ANY IDEAS
thanks.
booger351
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Post by booger351 »

found the problem.
.0047 cap on the back of mic jack going from audio to ground was bad, and tr31 and tr32 were GONE!! 32 is a beep oscillator(oh well) and 31 is the mic attenuator, all is good now except the beep, and the guy I fixed it for lives close sooooo. YAY no beep lol.
booger351
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Post by booger351 »

I just aligned this radio and I can only get about 10ma on the driver bias and is supposed to be around 50ma, does this mean the driver is weak or is it something else. I'm getting a 4 watt dead key with swing to about 25.
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Rick
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Re: President Grant DX Bias trouble

Post by Rick »

Check the feed resistor R261 (2R2) its probably o/c.
Rick.
booger351
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Post by booger351 »

r261 shows good 2.2 on the meter.
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Rick
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Re: President Grant DX Bias trouble

Post by Rick »

What dose the SSB TX audio sound?

What is the voltage at the base of the driver in TX on AM or FM and on SSB with no modulation?

What is the max power on SSB and AM/FM?
Rick.
booger351
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Post by booger351 »

The coil in front of the driver was touching one leg of the cap on the front of the driver, not sure if that was it, but I'm getting 50ma on the driver bias now, am power is 25 pep, ssb is around 30 pep.
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