Beating Noise emanating from the Printer Brother MFC8840D

k then amplifer is the culprit.

It's locked up because of a thread jam. See this page for more info.
http://welcome.solutions.brother.com/BSC/public/us/us/en/faq/faqh/000000/000000/000068/faqh000068_000.html?reg=us&c=us&lang=en&prod=hf_es2000teus

Loosen the two small screws under the flash on the swivel head. Turn flash on. You may need to twist the head just slightly. Flash bulb moves back and forth in the swivel head when zooming. If you dropped the flash, this may have jarred it from the track. I had the same problem with mine, and the above solution fixed it. Zoom works again and no clicking noise. Let me know.

One reason why the cartridge is making a clicking noise is that there is a washer and spring missing from the inside of the cartridge

if this is the case you will need to buy a new cartridge as it can not be solved until the washer and spring are put in

The beep noise three times indicates taht there is an error or one of the buttons are stuck.

Please turn off the Brother and press down on each button.

Check your oil pressure!! Sounds like a loud lifter or maybe valve

For a possible fix to the Brother HL-2140 squeal/squeak/noise problem open the printer at the other side from the paper tray and toner cartridge door. You should see a little black roller rod along with some white wheels.

The noise may be coming from the contact between the wheels/rollers which pull paper toward the output tray on top after it has been printed.

Check and clean/wipe the wheels and black rod, especially in the center area. Hopefully the noise will now be reduced/eliminated.

Cheers, Stephen

This can be all that is pleased , main reason there is defect of lubrificant there where this it is necessary, recommend you to apply to nearest service.

Sounds like you lost the High Voltage. The beating sound is the power supply trying to start up. After a predetermined time it will quit to protect the set. This is a very common problem and typically not that much to repair. If you are not an electronics repair technician you should find a reputable repair shop and enlist their services. I would not think the cost should exceed $150.00 to repair. Good luck.