Hum on one side only

ozzynet

I am getting hum on one side of the driverack pa.
The transformers were buzzing initially, so replaced these.

If I connect the dr to the amps without any input connectors, the system is fine.
When I connect the desk to the pa a hum starts on the left side. Have tried swapping leads and hum is still present.
Have also tried reversing the left and right leads around and hum is still on the left output.
DR is setup 2X3. Have also tried setting it up to utilize the mid outputs but there is still a hum on the left side.
Have substituted the DR for a lower priced piece of equipment and the hum disappears. Therefore the DR is inducing the hum.

Any help will be appreciated.

Also is there somewhere in the UK that services these?

Dennis

Have you tried engaging the pin 1 lift switch on the back of the unit? Where is the unit located in relation to your audio amplifiers and/or mixer power supply?

Dennis

ozzynet

Yes I have tried the ground lift, if it was a ground problem, then it would happen on both left and right channels.
I am presuming that it is a filtering problem on the circuit board.
Is there any service places in the UK, failing that has anyone got the schematics for the PA

Dennis

All I can come up with is the UK distributor-

SOUND TECHNOLOGY
LETCHWORTH POINT LETCHWORTH GARDEN CITY
HERTFORDSHIRE SG6 1ND EN6 3JN UNITED KINGDOM
Tel. 01462 480000
Fax. 01462 480800
E-mail: info@soundtech.co.uk
www.soundtech.co.uk

They should be able to answer your questions. Maybe Gadget will jump in here with info I don't have.....

Dennis

ozzynet

Thanks for that, but tried getting the new transformers from them, and they only will supply to dealers, so had to order through LMC to get them.

Need schematic for this or a service centre in UK to get this fixed.

Gadget

Well.. I'd suggest Tech support...
http://www.dbxpro.com/contact_tech_support.php
Gadget