This old Galaxy has good carrier but no modulation
A friend of mine broght his radio to me said the radio keys up but no one can here him, I put it on the power supply and hooked it up and sure enough no modulation, which chip is the audio chip? I looked and it could be c133, or tr34 or tr53, but I am curious, because I don't know where to start. hope someone has fixed this before, thanks,
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Deadkey is slang it is CW or Carrier wave which is RF power produced before modulation/audio is mixed in which stimulates PEP wattage slang being SWING WATTS. A Watt Meter is used to measure it which is often a combination device Wattage/SWR/Modulation meter.
It sounds like you had a cold solder joint. Leaving it in the sun probably temporarily corrected it. I would take it to a tech to have all the solder joints corrected, unless you are handy with a soldering iron. The problem will most likely come back.
All you have to do is pull the top cover off, which will show the bottom, or trace side of the board. Using a soldering iron, make sure any solder joint that doesn't fully look soldered and make sure the solder is fully covering the joint. If need you may have to add solder.
As for the frequency counter going nutty when you modulate, Don't worry about it. There is nothing wrong. Because when you modulate you are modulating the carrier signal you are changing the signal so the counter will interpret that as a different freq because it cannot differentiate. Freq counters are for use with carrier only. As long as the carrier shows correct, it is right.
That linear will be good for 100 watts of clean power. It has two MRF455 transistor which are 60 watts a piece. The cb will drive it with the carrier or dead key reduced to about 1.5 to 2 watts but i suggest that you read the linear's power while adjusting dead key not exceeding the 100 watts pep with voice.
An NPC mod would be a good addition to get the modulation up with a low dead key.
Before you start the projection make sure you antenna system is in good condition high SWR will smake you linear in a hurry.
In factory condition 949 galaxy with a 3.8 carrier it will drive a 667v TexasStar. It is a low drive linear that will end all disputes as to who has more power. 8 out of 10 birds that escape will die of cancer withiin 72 hrs. Ok could not help myself. I would not suggest that unless you just want to damage other peoples receive. The v is for variable power. Hope this was of help.
You may have a dead meter.
Modulation is audio's affect on swing wattage or pep. Notice that needle moving more with your voice.
Dead key or carrier wattage is without your voice enhancing the power only with mic keyed.
I can only assume that the chipset you are referring to is an ic chip audio or pll which must be working if you are receiving audio.
Check your mic cord................ transmit and modulation and even your receive volume can be affected by the cord/mic plug solder joints or broken wires here.
http://www.cbtricks.com/radios/galaxy/dx33hp2/graphics/dx_33hp2_sch.pdf this is a similar radio the General Lee, Connex 3300hp and Galaxy hp2 share boards i believe dont hold me to that thou.
To do it correctly you will need a Scope so that you can see when the Audio equals the RF Transmit power if it is Less it is not efficient. If it is more it is Over Modulating and splattering and not giving you intelligible transmitted signals. The best way is to get an old copy of the Radio Amateurs Handbook from the late 50s to the early 60s they have a circuit you can build to watch Modulation on an FR Carrier that will do exactly what you want.
This sounds exactly backwards, you should have a carrier on AM with some forward swing, on SSB (sideband) there should be no carrier & all modulation (forward swing). Could you have the settings mixed up or has somebody put a modulation kit in your radio & messed something up or maybe one of the knobs has been removed & not replaced correctly ? Just a couple of things you might look into.
sounds like your audio chip is gone. When you say it shows carrier signal is it just showing dead key or does it show modulation when you talk? 85% chance its audio chip without having it in front of me i couldn't tell for sure.