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Galaxy Saturn (not turbo) loud power supply hum/buzz? Nelp?

Posted: December 23rd, 2020, 8:18 am
by adamf

Hi all, I have a Galaxy Saturn (not turbo) and this evening when I went to transmit there is a pretty loud buzz/hum. When I am not transmitting I can hear it a little when volume is turned down but when I transmit it's fairly loud. On AM it's loud and on SSB it's low until I modulate and gets louder as the output increases with modulation. I did not opened the radio but I will try to tomorrow so perhaps someone may be familiar and tell me what to look for? I know to be careful and I am fairly handy. Thanks for any help. Adam

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Added 14 hours 1 minute 6 seconds after previous.
Hi, so I opened up the radio and when I transmit the power transformer is buzzing, if I press on top of it to stop some of the vibration it lessens, can it still be the bridge rectifier? If not does anyone know what I can do? Thanks, Adam

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Hi all, I am not the best at this, can I do a simple test on the power transformer? It has 2 wires in and 2 wires out. On the 2 wires in I should get 120VAC give or take, yes? On the wires out BEFORE the bridge rectifier what should I see approx for VAC output? Thanks, Adam

Galaxy Saturn (not turbo) loud power supply hum/buzz? Nelp?

Posted: December 23rd, 2020, 11:18 am
by MDYoungblood
Most times the hum or buzzing sound is caused by the capacitors in the power supply section are going south. since you still have enough output to transmit, it is probably just one but it would be best to replace them all because of the age of the radio. Don't have a schematic so I can't say the test points for 120acv or the side of the rectifier that should be 13.8dcv.

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Greg

Galaxy Saturn (not turbo) loud power supply hum/buzz? Nelp?

Posted: December 23rd, 2020, 12:27 pm
by adamf
Hi Greg, I would up taking out the transformer etc and replaced it with a switching supply, works very now and quiet! Thanks, Adam

Galaxy Saturn (not turbo) loud power supply hum/buzz? Nelp?

Posted: December 23rd, 2020, 12:41 pm
by MDYoungblood
adamf wrote: December 23rd, 2020, 12:27 pm Hi Greg, I would up taking out the transformer etc and replaced it with a switching supply, works very now and quiet! Thanks, Adam
That is actually the best thing to do, and I think Mega-Watt is still a sponsor here. I believe this one will fit,

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Greg

Galaxy Saturn (not turbo) loud power supply hum/buzz? Nelp?

Posted: December 23rd, 2020, 1:18 pm
by Bozo

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