Delta 1 , now I know what you are talking about. Oldtech can have it. I appreciate the offer but I am loaded down with radios.
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Another PC122XL TX Problem
- Thread starter Low_Boy
- Start date
Andy i can adjust SM power from 0 to 8 watts. The caps you mentioned have been changed. I do not have a cap on the solder side like in your picture. Let me re cap the rest of the radio and we will go fr there.
That cap is a tone mod for the ex-XYL - she didn't appreciate the shrill-ness of the small speaker in it - so I added a cap to help with the tone so she could hear better.
Good luck on this - I hope it is something simple...
Good luck on this - I hope it is something simple...
I do not have many more left to change. About 6 I think. So far changing the 3 that were not changed in the PLL section did nothing. With no limiter tapping on the Mic will swing it right up but after doing this or saying test 3 or 4 times it poops out after waiting a bit it will swing back up but only for a word or 2. Possibly something getting hot.
We can now rule out electrolytic capacitors all have been changed. Still the same thing I get modulation when saying Au, and then modulation falls off for the dio part of audio. Can turn dead key to 8 watts and the PA works and sounds great. Any more ideas?
Take a pic or two - need to see the Mic section and AM Regulator because the AM regulator, in the back - may have some broken traces - that may mean a broken resistor so you may need to do some more voltage checks.
Audio would work better if AM carrier was lowered to 3 watts - you'll get plenty of swing too - and swing equates to the level of quality the AM regulator is - if audio "clips off" there may be an issue with the audio to bias mixing going on - because the Mic amp may be perfectly fine.
The communication from the mic amp to the am regulator may be bad - damaged.
:+> Andy <+:
Audio would work better if AM carrier was lowered to 3 watts - you'll get plenty of swing too - and swing equates to the level of quality the AM regulator is - if audio "clips off" there may be an issue with the audio to bias mixing going on - because the Mic amp may be perfectly fine.
The communication from the mic amp to the am regulator may be bad - damaged.
:+> Andy <+:
I have been testing with 3 watts of dead key and limiter still removed. Running out to cut the lawn now that things are dry outside and will post pictures when i get back in.
Thanks.
Thanks.
Waited until 2:45 pm lawn was still a bit wet but it got cut anyway. This pic. is from my phone
If not good enough I will take another with my camera. I cleaned up some factory flux
It looked pretty bad.
If not good enough I will take another with my camera. I cleaned up some factory flux
It looked pretty bad.
Rubbing alcohol and an old trimmed down tooth brush will knock off even the most stubborn solder flux deposits and render it spotless.
What did you use?
What did you use?
Yes infact took it out in the beginning it checked good. I put it back in then decided to replace it when I replaced all the caps. So it is new.
There's not much else I can think of at the moment - it appears the radio works, I just can't locate the cause of the voltage rise for cutout - except a bad solder joint, or broken part.
Going ovr this, you say,
AM power is adjustable - so VR 10 appears to be ok,
That can affect Q36...but you'd have no control of carrier power then....
First syllable is heard before cutout...
Are the Mic wires routed correctly?
You know there are two spots and the Pin 2 one goes closest to R159 R161 and that should be your WHITE wire.
BLACK wire goes right next to it towards the center of the board that next circle right by it.
Now, the element you have is dynamic, means it's a coil with some resistance to it - so it will IMPEDE a voltage flowing thru it.
I'm wondering if the Mic jack pin 2 is not quite right - yet...
Referring to CB/PA switch which tells a diode to ground or not - D44. So if the CB/PA switch is bad, speaker would route audio to PA jack and you'd hear RECEIVE thru it, and MIC Audio if D38 works right.
IF D44 works correctly - the PA would work, and you'd have receive. But if PA was on all the time between the two - we may have to recheck D44 in continuity thru that switch - for if it grounds all the time, that's a no-no.
Because of power sharing in the mic line, if the other side of the CB/PA switch was working right, your speaker would work, but audio would get killed.....
So look at PA audio - why? A resistor of 1.5K or less is used, and it can "suck" all the audio to it but have no where to go - killing your audio because the CB/PA switch isn't right...you mute the Audio Amp chip on TX because that is working right...speaker side or not - TX light is on and you're on the air.
Again, go over the pics I sent of my front panel board, make sure your switches and foil to ribbon cable traces are clean - take you time - I hope for the best...
:+> Andy <+:
Going ovr this, you say,
AM power is adjustable - so VR 10 appears to be ok,
That can affect Q36...but you'd have no control of carrier power then....
First syllable is heard before cutout...
Are the Mic wires routed correctly?
You know there are two spots and the Pin 2 one goes closest to R159 R161 and that should be your WHITE wire.
BLACK wire goes right next to it towards the center of the board that next circle right by it.
Now, the element you have is dynamic, means it's a coil with some resistance to it - so it will IMPEDE a voltage flowing thru it.
I'm wondering if the Mic jack pin 2 is not quite right - yet...
Referring to CB/PA switch which tells a diode to ground or not - D44. So if the CB/PA switch is bad, speaker would route audio to PA jack and you'd hear RECEIVE thru it, and MIC Audio if D38 works right.
IF D44 works correctly - the PA would work, and you'd have receive. But if PA was on all the time between the two - we may have to recheck D44 in continuity thru that switch - for if it grounds all the time, that's a no-no.
Because of power sharing in the mic line, if the other side of the CB/PA switch was working right, your speaker would work, but audio would get killed.....
So look at PA audio - why? A resistor of 1.5K or less is used, and it can "suck" all the audio to it but have no where to go - killing your audio because the CB/PA switch isn't right...you mute the Audio Amp chip on TX because that is working right...speaker side or not - TX light is on and you're on the air.
Again, go over the pics I sent of my front panel board, make sure your switches and foil to ribbon cable traces are clean - take you time - I hope for the best...
:+> Andy <+: