12 Volt TV buzzing when on mains hook up - Motorhome Forums, Motorhome Discussion, Motorhome Chat

User Tag List

 
LinkBack Thread Tools
post #1 of 7 (permalink) Old 18-07-2012, 20:45 Thread Starter
Senior Member
 
Join Date: May 2005
Posts: 659
Thanks: 0
Thanked 1 Time in 1 Post
12 Volt TV buzzing when on mains hook up

Hi folks

As we're not often on hook up I'd not noticed this problem until a couple of weeks ago.

The TV used in my MH is a 12 volt version operating through a regulated 12 volt supply (black box 12v dc to 34v dc input regulated to 12 volt dc output).

This works beautifully when run purely off the leisure batteries (i.e. no 240v hook up). However, when the 240 volt mains hook up is connected, firstly I lose the sound on the TV and then it appears the voltage regulator starts buzzing.

Obviously, by switching the 240 volt circuit breakers off, everything is back to normal.

Anyone out there had this problem or know how to rectify this problem?

Keith (Sprokit)
sprokit is offline  
Sponsored Links
Advertisement
 
post #2 of 7 (permalink) Old 18-07-2012, 20:50
Senior Member
 
Zebedee's Avatar
 
Join Date: Oct 2007
Location: Worcestershire
Posts: 23,180
Thanks: 31
Thanked 128 Times in 101 Posts
Hi Keith

Yes, we had a very similar problem, but I doubt if I can give you much direct help.

Our charger unit is a Sargent EC325 (from memory) and when I asked them about it they were aware of the problem, and said it was very uncommon. They fixed it free of charge, but I did have to send the unit back to them.

Don't know what you would have to do for your unit, but possibly a similar cure. It was definite interference from the charger unit.

Dave
Zebedee is offline  
post #3 of 7 (permalink) Old 18-07-2012, 21:12 Thread Starter
Senior Member
 
Join Date: May 2005
Posts: 659
Thanks: 0
Thanked 1 Time in 1 Post
Quote:
Originally Posted by Zebedee
Hi Keith

Yes, we had a very similar problem, but I doubt if I can give you much direct help.

Our charger unit is a Sargent EC325 (from memory) and when I asked them about it they were aware of the problem, and said it was very uncommon. They fixed it free of charge, but I did have to send the unit back to them.

Don't know what you would have to do for your unit, but possibly a similar cure. It was definite interference from the charger unit.

Dave
Thanks Dave

But are you talking about the Sargent unit buzzing? There's no noise from the region of my Elektrobloc unit.

Perhaps I didn't make it very clear, its the TV 12 volt regulator box which starts buzzing on hook up.

Any other ideas?

Keith (Sprokit)
sprokit is offline  
 
post #4 of 7 (permalink) Old 18-07-2012, 22:39
Senior Member
 
gaspode's Avatar
 
Join Date: May 2005
Location: Exiled in Surrey
My Motorhome: Rapido 7066DF
Posts: 13,707
Thanks: 53
Thanked 269 Times in 220 Posts
Personal Aire
Quote:
Originally Posted by sprokit
Any other ideas?

Keith (Sprokit)
Hi Keith

Throw the regulator box away, you almost certainly don't need it.

We have a similar problem with buzzing through the TV sound when the solar panels are working hard, I know others who have similar problems. I assume it's due to the regulator pulsing, probably your charger pulses at some time in its charge cycle? I have a switch on the solar panel output so in the unusual instance of wanting the TV on when the sun is shining I just turn the panels off.

I've used no end of 12v TVs running directly from the van 12v supply and never experienced the slightest problem, most TVs will tolerate voltages well above the nominal 12v and if your battery is at less than 12v - well you shouldn't be using the TV anyway should you?

Help someone out when they're in trouble and they'll remember you when they're in trouble again.
gaspode is offline  
post #5 of 7 (permalink) Old 19-07-2012, 00:21
Senior Member
 
Zebedee's Avatar
 
Join Date: Oct 2007
Location: Worcestershire
Posts: 23,180
Thanks: 31
Thanked 128 Times in 101 Posts
Quote:
Originally Posted by sprokit
But are you talking about the Sargent unit buzzing? There's no noise from the region of my Elektrobloc unit.
No Keith - I didn't make it clear enough either.

This was sound from the TV speaker, with a slight visual disturbance on the picture was well. The buzzing started as a slow ticking, gradually increased in frequency until it was a buzz, then tailed off again.

From memory, each period of fizzing/buzzing lasted about 8 seconds and there was about a 20 second silence before the next cycle began. More irritating than a constant buzz, which could probably have been mentally "tuned out" to some extent.

Sounds like it's the same as what Gaspode has described. Ours is now virtually cured, though there is still a very faint buzzing to be heard during silent periods of a programme.

Dave
Zebedee is offline  
post #6 of 7 (permalink) Old 19-07-2012, 09:39 Thread Starter
Senior Member
 
Join Date: May 2005
Posts: 659
Thanks: 0
Thanked 1 Time in 1 Post
Many thanks guys.

Ken, I have leads I can use to make a direct feed to the TV rather than through the voltage regulator - I'll give it a try.

Dave, again thank you, if the plain lead doesn't work I'll see what can be done with the Elektrobloc.

Keith (Sprokit)
sprokit is offline  
post #7 of 7 (permalink) Old 19-07-2012, 18:26
Senior Member
 
Join Date: Mar 2011
Location: Mayenne, France
Posts: 1,369
Thanks: 0
Thanked 1 Time in 1 Post
Is it a 12v telly plugged into a 12v socket and only buzzes when on hook-up?
If so, I have experienced the same problem and it was a dodgy connection at the 12v socket. I can usually sort it by wriggling the 12v plug a bit.

Not very scientific but it works for me
Scattycat is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Motorhome Forums, Motorhome Discussion, Motorhome Chat forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome