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andypag · 02-11-2021, 00:15

Over the last month my VHF volume has been getting quieter and harder to hear.

What are the likely causes and remedies?

Joh.Ghurt · 02-11-2021, 04:48

I would guess it could be corrosion on the antenna connector up the mast.

CaptTom · 02-11-2021, 05:18

I was going the other way; corrosion or moisture in the speaker or speaker connections.

I guess it depends on the symptom. To me "quieter" suggests that the signal is still received and as clear as before, but the volume is lower.

Is it the built-in speaker, or one plugged into the device?

thomm225 · 02-11-2021, 05:26

First question would be how old is your VHF?

It could be something as simple as a dirty volume potentiometer.

You know like on your old stereo where the fix would be to turn it back and forth a few times to "clean" it a bit then the volume would come back up.

Stewie12 · 02-11-2021, 09:24

If it is the volume control it would probably crackle as you moved it. Switch cleaner would fix that , but you would have to open the radio up. Probably a job for a professional.

oleman · 02-11-2021, 12:22

Simple troubleshooting would be to get another transceiver and plug it into the system to rule out/in the antenna and antenna environment. I assume it is on a mast and a PITA to access. Also will rule out/in VCC and Ground issue. Is the speaker in the handset, famous for getting beat around.

Good luck with your comms.

Bycrick · 02-11-2021, 13:51

Audio volume has nothing to do with received signal strength on FM radios. Corroded wires in the speaker circuit almost always show up as "no sound" although I did once-open-a-time see corrosion around the speaker voice coil. The friction reduced the movement of the cone, and thus the sound. My first guess would be something in the audio amplifier circuit has changed value. An old Icom 705 showed similar symptoms until the audio amp IC finally failed catastrophically.

GreenWave · 02-11-2021, 14:45

Quote:

Originally Posted by Bycrick

Audio volume has nothing to do with received signal strength on FM radios. Corroded wires in the speaker circuit almost always show up as "no sound" although I did once-open-a-time see corrosion around the speaker voice coil. The friction reduced the movement of the cone, and thus the sound. My first guess would be something in the audio amplifier circuit has changed value. An old Icom 705 showed similar symptoms until the audio amp IC finally failed catastrophically.

100% this. If the voume is clear and just lower level then it isn't the antenna or the volume switch. Something is reducing the voltage/current driving the speaker most likely.

billgewater · 02-11-2021, 15:33

My spouse accuses me of going deaf. Could it be that . . . .

SeanPatrick · 02-11-2021, 17:24

Quote:

Originally Posted by billgewater

My spouse accuses me of going deaf. Could it be that . . . .

Ha! This was my first thought, too. Reminds me of when I visited my old elementary school and was baffled as to why they had lowered the ceilings.

andypag · 02-11-2021, 23:52

Thanks everyone. It's not signal issue as the button-press-beeps are also quieter. Somewhere on the amplifier circuit. I figured it was a failing capacitor somewhere.

I opened it up. All the caps looked fine. Contacts to speaker were fine. Speaker impedance 16ohms (although this was while it was still connected so not sure that's a valid measurement).

But there were some white residue patches on the circuit board. So rinsed it all with isopropyl alcohol, cleaned it up with cotton buds and it seems to be working correctly now. Will give it a longer test tomorrow.

Seems strange to have water intrusion as the radio is inside at the chart table and the case seal was really good.

Hopefully that's a permanent fix.

BrianGJS · 03-11-2021, 18:09

The first thing I would do is plug in an external speaker if there is a jack on the back of the radio. I have had to replace a few speakers in VHF radios and if the external one worked an internal speaker replacement generally worked. Digikey is a good source for speakers.

flightlead404 · 03-11-2021, 19:50

Quote:

Originally Posted by billgewater

My spouse accuses me of going deaf. Could it be that . . . .

No joke, it could be. I'm only 55 but am frequently rebuked for yelling at people (especially when I'm excited) or having the TV etc on too loud.

Too many years around loud engines, firearms etc

A hearing test might be valuable.