since it is a 44V you can unhook the mic and still have receive. see if the noise goes away with the mic unplugged. I had one a few years ago the 1000uf filter cap was weak and letting it make noise. also what meter light is in the radio. some times a LED bulb can cause a problem. the worst ones is the color changing LED's. ever time the color changes it makes a noise in some radios.
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Help with Galaxy CB humming issue.
- Thread starter Radio Face
- Start date
Could be as simple as a bad cap or it might be an issue with the VFO.
I hate it when I repeat an answer but your best bet it to pretend you are doing an alignment on the radio and follow the Sams Photo Facts listed alignment.
If this was a stereo component and it just suddenly start to hum without any trama I again would suspect a bad cap before anything else.
I hate it when I repeat an answer but your best bet it to pretend you are doing an alignment on the radio and follow the Sams Photo Facts listed alignment.
If this was a stereo component and it just suddenly start to hum without any trama I again would suspect a bad cap before anything else.
Someone has installed a color changing led meter light. Hmm? Now that may be something.
Hi folks, just want to bring this to your attention.
The 44V has had two types of Echo boards used...
You can find a lot of the data by Clicking here at CB Tricks
And possibly 3 if the board is a 50C - stolen from an even more obsolete radio - 2517...
One the boards provides single ground sourcing and the other a ground loop between two grounds on the main PCB.
So essentially, the Echo board is shielded thru the main PCB, but uses the shield from the Mic connector - that if the two wires from the mic ever got swapped, the moment the line that shield is on, became disconnected - like Pin 4 - it was supposed to "short" to Pin 1 - but here's the rub...
The MIC connector the 3-pin from the Echo board to the main PCB, then there is another ground that is the keying circuit that is usually left open - pin 3 that grounds to pin 1.
Some fixes I've done simply needed to have the "open pin 4" at the mic jack -shorted to pin 1. It's not always the fix though...
The problem - two different potentials and the Mic's 3-pin Front-Of-The-Board-Mic Key connector - ground versus the ground back towards the Audio Chip and the keying circuit return located BETWEEN the two.
So if you TX and there is no hum, then the Mic is providing the ground shield - if the Hum still occurs when in TX or RX - then the main PCB board ground loop is the culprit and you have to verify all ground from the Mic, to the Echo board(s) (Note
Plural) used and then to main PCB ground.
This is an assembly problem more than an electrical component problem - you may have acquired the radio with the board removed - which is one one situation or you have a different board than the original one installed - a different situation.
Your Mileage may vary, No Warranty is Expressed or Implied, proceed at your own peril...
:+> Andy <+:
The 44V has had two types of Echo boards used...
You can find a lot of the data by Clicking here at CB Tricks
And possibly 3 if the board is a 50C - stolen from an even more obsolete radio - 2517...
One the boards provides single ground sourcing and the other a ground loop between two grounds on the main PCB.
So essentially, the Echo board is shielded thru the main PCB, but uses the shield from the Mic connector - that if the two wires from the mic ever got swapped, the moment the line that shield is on, became disconnected - like Pin 4 - it was supposed to "short" to Pin 1 - but here's the rub...
The MIC connector the 3-pin from the Echo board to the main PCB, then there is another ground that is the keying circuit that is usually left open - pin 3 that grounds to pin 1.
Some fixes I've done simply needed to have the "open pin 4" at the mic jack -shorted to pin 1. It's not always the fix though...
The problem - two different potentials and the Mic's 3-pin Front-Of-The-Board-Mic Key connector - ground versus the ground back towards the Audio Chip and the keying circuit return located BETWEEN the two.
So if you TX and there is no hum, then the Mic is providing the ground shield - if the Hum still occurs when in TX or RX - then the main PCB board ground loop is the culprit and you have to verify all ground from the Mic, to the Echo board(s) (Note
Plural) used and then to main PCB ground.This is an assembly problem more than an electrical component problem - you may have acquired the radio with the board removed - which is one one situation or you have a different board than the original one installed - a different situation.
Your Mileage may vary, No Warranty is Expressed or Implied, proceed at your own peril...
:+> Andy <+:
If the sound of the noise fluctuates in step with a color-changing LED, that settles it.
The fix is simple. Take the ground wire loose from where it's soldered to the front-panel circuits. The original meter lamp's ground wire is not suitable to use for color-change LEDs.
Or just cut the ground wire. Strip the end and splice a wire long enough to reach the big filter cap towards the rear of the main pc board. On the solder side of the pc board, directly under that cap, solder the end of the new ground wire to the ground foil under that big cap.
Usually fixes this fault.
73
The fix is simple. Take the ground wire loose from where it's soldered to the front-panel circuits. The original meter lamp's ground wire is not suitable to use for color-change LEDs.
Or just cut the ground wire. Strip the end and splice a wire long enough to reach the big filter cap towards the rear of the main pc board. On the solder side of the pc board, directly under that cap, solder the end of the new ground wire to the ground foil under that big cap.
Usually fixes this fault.
73
I did notice that the noise stops when I key the mic. I will unhook the LED and see if that helps. I notice that there is a sound that fluctuates with the LED changing colors but that is a different sound than the humming if that makes sense?
he is talking about the main board ground. . hook it up towards the rear of the radio where the large cap ground lead is soldered to the board. before worring about the hook up point make sure that is the problem
they have 2 different flashing LED's. on a slow flashing one and the other is fast flashing.
on the ones I have used one would make a noise almost constantly and the other only when the color changed.
1st just unsolder one leg of the light and see if that stops your noise problem. if not you will have to move on.
they have 2 different flashing LED's. on a slow flashing one and the other is fast flashing.
on the ones I have used one would make a noise almost constantly and the other only when the color changed.
1st just unsolder one leg of the light and see if that stops your noise problem. if not you will have to move on.
look at the parts layout of the link I left you here. top right corner is a cap marked C195.. flip the radio over and look where the neg leg of the cap solders and that will be the location Nomad is talking about.
http://www.cbtricks.com/radios/galaxy/dx44v/graphics/44v_3600-14b_top.gif
http://www.cbtricks.com/radios/galaxy/dx44v/graphics/44v_3600-14b_top.gif
Wow, forgot about that 5V zener - that can screw things up real quick...Dimmer function.
That can rectify the noise from those built in free running oscillators...
But did they even work?
WILD - reminds me of those being used in a Mic a friend wanted me to mod for him - and it precipitated from that...
:+> Andy <+:
That can rectify the noise from those built in free running oscillators...
But did they even work?
WILD - reminds me of those being used in a Mic a friend wanted me to mod for him - and it precipitated from that...
:+> Andy <+:
I did notice that the humming stops when I key the microphone. Also, I tried the stock microphone on it today and it doesn't make the humming? What are your thoughts?
- No one is chatting at the moment.
