Hello,

Recently i have been facing this problem with my Beosystem 9500. Everytime i switch on to Phono, there is a loud humming (50hz?) coming from the speakers. The records play normally, but the humming takes over the music. The power supplied for Beocenter and Beogram are from the same source. In addition, when i press Stop on beocenter while the record is playing, i hear a "cracking" sound from the speakers. I don't know how to describe it better but it's pretty much the same sound you hear if you unplug an auxiliary source (eg. iPod) without muting the speakers first.

Any ideas what's wrong?

Thank you in advance, sincerely

Olli
 

try separate power sources, see below...

power

Check the DIN plug of the Beogram - I wonder if the connection to the casing of the plug has become loose. Does it hum if you disconnect the Beogram?

Agree with Peter. Sounds like ground continuity between the beogram and beocenter.

No, it doesn't hum if i switch on to Phono with Beogram DIN disconnected, so that is propably the problem. I tried to move the connector a bit when it's connected but didn't make any difference on the humming so the wires inside the connector's casing could be completely loose. I'll open the connector and check the wirings.

Ok, i opened the casing and problem was with some parts of ground wiring touching other wires. The grounding wires were still attached to correct pin but as the peeled wires were not soldered completely to keep them in one bunch, some of the grounding wires were touching other pins as the din-cable twisted.

I also noted that the connectors on BC9500 are somewhat badly designed. All the DIN-connectors are positioned so that when you connect a cable, all the weight of the cable pushes against cable's connector and creates tension to the wires soldered to pins. I bought a third party DIN5-3,5mm adaptor and it has a "flexible part" after the connector to reduce this tension, as the default cable on Beogram doesn't...

Thanks for your help guys!
 

Result!

A good tip to prevent a re-occurrance of the wires shorting (courtesy of member Craig) is to filll the din plug casing with silicon sealant before reassembling.

 

Chris.

I have a small problem with humming aswell. My Beocenter 9000 keeps this low frequency humming all the time. Loud enough so you can hear it. I guess it is the transformer. Is this rather a feature of this system or can something be done to make it stop. Also when I pull the powerplug off the socket or put it back there is a loud bang from the speakers.

I agree that sounds like the transformer. Obviously the best way to fix this is to replace the transformer but these are not readily available. Quick trick! I had a Beomaster 3000 that hummed and the table it was on seemed to amplify this. Two cut up squash balls made 4 half spherical isolating feet and this reduced the perceived hum so I couldn't hear it!

Yes, the table seems to amplify the low noise. I will try to damp it somehow. I think changing the transformer would be too difficult. Thanks for the tip about the squash balls! Anyone got ideas what the bang from the speakers is about ,when pulling the power-plug off