radio noise

[dean hanson]

Bill;

I was having problems getting my rear battery to charge in the Avion and
thought I would have to run another isolated wire direct. Further
investigation found a 30 amp fuse that looked good was really burned out.
There is no noise from my converter but with the coached on shore power and
the new fuse plugged in, the rear speakers (with the radio off) both hum
like the sound of a battery charger. That drove me nuts until I found the
source. Something is in those speakers to make that happen.



Dean C. Hanson 75 Avion

Fremont, Ca. 94536

(510) 657-9600

 

[terry1]

Not in the speakers, in the amplifier connected to them. What you are hearing is the reverse leakage current through the transistor amplifier that
powers those grounded speakers. Indicates a wave of AC current on the charge circuit or weak reverse voltage characteristics of the amplifier.
--
Terry Kelpien

ASE Master Technician

73 Glacier 260

Smithfield, Va.

 

[1976GMC]

I'm getting the same noise in all of my speakers. PO connected the stereo system to "Hot at all times" wire on the engine battery. Several times in
the past my engine battery got drained completely (had to start using the booster battery circuit). I think the battery drain is related to the
static noise in the speakers. For now, I just disconnected all of them and made a note in the "Fix this when you have time" list.
What is the best way to deal with this issue? Does it indicate a bad amplifier or the stereo system that needs to be replaced?
--
Vadim Jitkov
'76 Glenbrook 26'
Pullman, WA

 

[d c *mac* macdonald]

Many "12 V" devices in today's world are actually "HOT" all the time but are switched "ON" by internal circuitry. If one or more of those devices in the apparatus goes shorted (or even just leaky), it WILL drain the battery and fairly quickly, at that.

D C "Mac" Macdonald​
Amateur Radio K2GKK​
Since 30 November '53​
USAF and FAA, Retired​
Member GMCMI & Classics​
Oklahoma City, OK​
"The Money Pit"​
TZE166V101966​
'76 ex-Palm Beach​
k2gkk + hotmail dot com
________________________________
From: Gmclist on behalf of Vadim Jitkov
Sent: Thursday, October 11, 2018 13:27
To: gmclist
Subject: Re: [GMCnet] radio noise

I'm getting the same noise in all of my speakers. PO connected the stereo system to "Hot at all times" wire on the engine battery. Several times in
the past my engine battery got drained completely (had to start using the booster battery circuit). I think the battery drain is related to the
static noise in the speakers. For now, I just disconnected all of them and made a note in the "Fix this when you have time" list.
What is the best way to deal with this issue? Does it indicate a bad amplifier or the stereo system that needs to be replaced?
--
Vadim Jitkov
'76 Glenbrook 26'
Pullman, WA

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[1976GMC]

Do you know what is "acceptable" current bleed on a "typical" CD/Radio unit? My guess if it bleeds due to internal circuitry malfunction it will be
above nominal stand-by amp flow.
--
Vadim Jitkov
'76 Glenbrook 26'
Pullman, WA

 

[terry1]

Standby current needs to be less than 10 ma for a month long storage with enough power left over to start the engine. 20 ma will shorten that time to
a week. YMMV, and weak batteries need not apply. Simple radios/cd players, etc. should be about 4 ma or less by themselves.
--
Terry Kelpien

ASE Master Technician

73 Glacier 260

Smithfield, Va.

 

[thomas phipps]

In the current MFJ catalog, on page 32 are several choices for RFI suppression chokes. Looking at ham radio stuff again. They have a web site. Put
'rfi' in search block. Many different options, cheap enough to try. Any interest, I came bring some to International Rally in Florida.
Tom
--
2012 Phoenix Cruiser model 2552
KA4CSG

 

[thomas phipps]

Check Amazon also. RF chokes are there, as well as RFI suppression.
Tom
--
2012 Phoenix Cruiser model 2552
KA4CSG