Troubleshooting external VHF speaker

tymonk · 11 Apr 2024

Hello. The external speaker on my Standard Horizon GX1100S VHF stopped working, briefly came back to life, and seems to have stopped altogether now. The manual only mentions a short circuit as a potential reason which I will check for but this seems unlikely (there is no continuity between the wires).

How can I best troubleshoot this? Should a voltage be measurable across the wires? I imagine this would only be so if sound is being transmitted. Would static noise with the volume turned up and squelch down suffice for this?

Would like to exhaust all options before I buy a new external speaker (or a new VHF...) Thanks in advance.

KompetentKrew · 11 Apr 2024

Surely just a bad connection at one end or the other - inspect and wiggle the connectors thoroughly.

If that doesn't show anything obvious then dismount the speaker and use electrical tape to mount it right next to the radio - find some spare 6" wire to connect it.

The radio's manual says the external speaker is 4Ω - probably any 4Ω speaker will do. I bought a Visaton 2128 water-resistant speaker for my B&G VHF, although I haven't fitted it yet. £20.

EDIT: you can probably get a cheap non-waterproof 4Ω speaker to test with for £5.

tymonk · 11 Apr 2024

Thanks for the suggestions.

Refueler · 11 Apr 2024

I have an old small speaker ... I use that with croc-clips to test speaker lead and if any output ..

tymonk · 14 Apr 2024

Connections all seem fine but oddly I can measure continuity between the 2 wires that come straight from the VHF. This would suggest a shortcircuit inside the VHF... Does this sound familiar to anyone or any ideas/suggestions? Thanks.

Daverw · 14 Apr 2024

You cannot check the output connections with a normal meter, I short circuit will also most likely blow the internal amp that feeds the speaker

William_H · 15 Apr 2024

The speaker will be described as a 4 ohm speaker. That is the impedance to AC. The DC resistance as measured by a multimeter will be around 1 or 2 ohms. So measuring resistance at plug to radio might make it appear to be a short circuit but is correct. Using a multimeter on ohms scale across the wires either at the speaker itself or at the radio end usually produces an audible click. (a 1.5v battery will do same thing) Yes the fine wires in the speaker coil can fail from corrosive atmosphere requiring speaker replacement but do check out plug in top radio (common fault area) and wires them selves. ol'will

Refueler · 15 Apr 2024

tymonk said:
Connections all seem fine but oddly I can measure continuity between the 2 wires that come straight from the VHF. This would suggest a shortcircuit inside the VHF... Does this sound familiar to anyone or any ideas/suggestions? Thanks.

Metering will be non conclusive ... just look at replies you have about it ..

The only sure way to check - is to try another known working speaker ... even if its not same OHMs rated ... its only a quick test ..

wonkywinch · 15 Apr 2024

Daverw said:
You cannot check the output connections with a normal meter, I short circuit will also most likely blow the internal amp that feeds the speaker

Only if the amp was designed more than 40 years ago. Almost all modern amp/output stages can handle short term shorts.

KompetentKrew · 15 Apr 2024

And also use a pair of fly leads, 1m or less, just spare wire that you find somewhere, to rule out the run of wire though the boat and the connectors.

This is at least as likely as anything else, and by using fly leads you rule it all out (or prove) in moments.

Troubleshooting external VHF speaker

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