Ground loop interference with laptop and external monitor

[ianmacd]

If I remove the Power supply to the monitor, the buzzing goes away.

Along with the pic on the monitor .

 

[robodan]

Think i'm going to have to reccomend to the management we provide universal Adaptors to those out in the field already. Any further sales of this product should halt immediatley.

 

[spinlondon]

Along with the pic on the monitor .

It's not the power, it's the feed to the speakers.

 

[spinlondon]

nope, used UPS and still same issue, although UPS is not a particularly great one to be fair

What's it like if you run the monitor on it's own through the UPS?

 

[robodan]

Didnt try that, wont be able to today i dont think.

It is one irritating problem this, with no easy solution.

Toshiba incidentally provide a 2pin AC Adaptor, as well as a 3pin, so I have ordered one to see if this helps.

The thinking is that if it is a Toshiba proved part then will be safe to use and I can give them to the customers with the problem.

 

[agulesin]

Toshiba incidentally provide a 2pin AC Adaptor, as well as a 3pin, so I have ordered one to see if this helps.The thinking is that if it is a Toshiba proved part then will be safe to use and I can give them to the customers with the problem.

2 pin equals 3 pin without earth - looks like we've got ourselves into a loop as well... O)

I've had the same problem since adding an LG LCD monitor to my HP laptop so don't think it's make/model specific. Have been searching for "VGA isolator" on the web all morning but no luck so far.

Also tried making an isolator from 15 M-F plug/socket and leaving the shells isolated but no effect - it's not that simple!

Some useful reading here.

 

[Lurch]

Some useful reading here.

That doesn;t look cheap, put that down as plan B after changing the power supplies to class 2 devices!

 

[mojorebel]

I have been away and missed the threads to this- I suggested a galvanic isolator because the problem of ground loop interference is caused by mains frequency induction (causes the buzzing in the speakers and lines etc on the monitors) - Removing the earth does work this is very iffy - but not as iffy as fitting a a GI (galvanic isolator) (which is contrary to BS7671 ) , GI's are used on ships as they remove the link to earth but restore it under fault conditions. We had a similiar problem connecting a touch screen jukebox to a 8 channel amp the amp suffered from ground loop frequency buzzing- we solved the problem by using an optical link between the Juky and the amp