Help!

Sorry to bother you all with a non-musical query, but I'm really stuck, and the Mudcat ALWAYS comes up trumps!

I've got a Brother HL-1030 Laser printer, and very nice it is too, or it was until this week.
Recently it has been printing 'dirty' copies. The control panel told me to replace the drum, so I did. At £85.50 + 17.5% VAT it's an expensive do.

No change.

The online help told me to replace the toner cartridge, so I did. At an additional £46.50 + VAT I'm now not too far off the price of a complete new printer.

Still no change.

The Brother website tells me to call out a Brother engineer...this will be VERY expensive. The local Brother office here in Manchester can't advise.

Any ideas anybody?

I guess there'll be some sort of high voltage bias twiddler on the PCB, but I can't locate anything without going for deep surgery.

BTW, I'm familiar with high voltage (1kv+)techniques, and have a reeasonable amount of test kit (meter, 'scope, etc.)

Thanks.

John