The Workbench

Re: US Beolab 4000 blown with UK voltage

Stoney3K — Tue, 08 Dec 2009 10:42:16 GMT

Die_Bogener:

The main transformer i dont remember... maybe some wire bridges or a new transformer.

I'd suspect the main transformer to have a set of windings for either 110/115V or 220/230V, the latter of course using twice the windings of the former. On a lot of A/V devices (not neccessarily B&O), the 110V live is connected to the primary center tap, where the 220V live is connected to the top winding, sharing a common neutral at the bottom. 110/220 operation is then selected through a switch. Buying separate transformers for the EU or US/JAP models would be logistically challenging, and therefore make the model more expensive for no apparent advantage.

The main transformer can usually handle quite the peak current, so your first course of action would be to check the fuses as said above. You can check for just a blown fuse by using an ohm meter (or multimeter on ohm or diode setting) across it. If it shows a low value, near zero, the fuse is good. If it shows an open connection (shown as '1 ' on the display), the fuse is dead.

Re: US Beolab 4000 blown with UK voltage

Die_Bogener — Mon, 30 Nov 2009 13:54:33 GMT

Is there still a red light?

If not, the small standby transformer could be gone. Can be replaced with a new board for the standby unit, or the transformer itself can be replaced. There is also a small fuse T63mA for the standby transformer. Test it with an ohm meter on the power cord. If resistance is open, then the fuse is blown... or the transformer. The US version has 2 fuses (F3+F4), europe just 1 (F5) !

The standby transformer board can easily be modified for 220V. Just remove F3+F4 and plug in F5. That's all for the standby.

The main transformer i dont remember... maybe some wire bridges or a new transformer.

Re: US Beolab 4000 blown with UK voltage

9 LEE — Sun, 29 Nov 2009 06:59:22 GMT

Firstly - don't feel too bad, your partner isn't the first to do this and won't be the last.

However, every single case i've known of this has led to the replacement of the frazzled components inside.. I've know Pentas, BeoLab 1's and a couple of classic items go this way, but maybe someone has internal knowledge of the 4000's.

Good luck - and welcome to BeoWorld by the way

Lee

US Beolab 4000 blown with UK voltage

kierondara — Sat, 28 Nov 2009 23:32:53 GMT

I purchased a set of Beolab 4000 bookshelf speakers in New York and enjoyed them thoroughly. They were of course rated for a 110 V mains supply. I brought them back to UK and planned to use them with a suitable step-down transformer to convert the 240 V UK supply to 110V.

My partner however inadvertently plugged them directly into the mains and reported that they worked for a few minutes and then stopped...

Now they are "dead" when connected to a 110V supply. Have they been irreparably destroyed? or is there (please!) just an internal fuse that has blown and needs to be replaced?