Ramps 1.4 + DRV8825 - Stepper motors work but are hissing

Hi Everyone,
First of all I apologise if this is a stupid post, it might be that all the information is out there but after 2 days of searching I just cant seem to find it!
I have a second hand Hictop I3 Printer which has been working ok , it has an obscure MPX.3 board which has very little support to be found and doesn't seem to like a few of my planned upgrades.
My new plan was to upgrade to a RAMPS 1.4 board and to that end I now have a robotale RAMPS board and 5 DRV8825 drivers.
Hictop seem to be pretty secretive about their product and so I cant find any specs for the stepper motors, so I measured the ref voltage on the MPX.3 and set the RAMPS drivers the same; 0.8v on X,Y and Extruder and 1v on Z.
When I power the board on its sounds fine but as soon as I move a stepper (any one) that stepper moves fine but starts to emit a high pitched or hissing noise while idle until the printer is reset.
I have tried turning the ref voltage down to 0.45v with no effect. I also tried removing jumpers to limit the micro stepping, down at 1/8 it did sound slightly better but still not great!
I have uploaded a video of the problem here; [youtu.be] this is moving 1mm each time the motor turns, the tone changes as the motor rotates. (it sound a lot louder in real life!)
I have checked the wire pairings are correct using a led between the pairs, and the wiring worked fine on the old board.
Apologies if this is a stupid post but if you can give me a hand it would be appreciated.

Thanks.

Edited 1 time(s). Last edit at 05/26/2017 04:30PM by Readie_s.

DRV8825 are not the best steppers around. They tend to make these hissing noise on 12V boards. You can hack them to work in a different decay mode, so they work better at slow speed. There also is an adapter board called TL smoother ( I believe ) that goes between driver and stepper to overcome these two issues.

Hi o_lampe,
Thank you very much for your reply. I wondered whether that was the case as most people seem to use the A4988 drivers. I will probably try some A4988 myself.
Thank you for your help, I didn't want to spend out on new drivers if the problem was with my steppers or ramps board. Been pulling my hair out trying to work out the problem!

Hey do you have any news?
im having practicly the same problem with about the same scenario. have you tired anything ?
here is what my printer sounds like https://youtu.be/uMm-g5ZPAPU (its abit quiet)
im having the bigest probelm with my z axis. its not moving properly.

Also my motors are getting so hot you coud burn your fingers but the ref voltage on the stepperdrivers is 0.8

-Sammy

Edited 1 time(s). Last edit at 07/01/2017 06:26PM by Speatzle_.

The Vref of the driver should match the current your stepper motors need. ( Usually 80% of max stepper current works best )
You could reduce Vref until the motors get warm but not hot or calculate Vref following this guide.

0.8V means a stepper current of 1.6A. That would suit a 2A stepper.

Hi Sammy,
You problem sounds identical to the issues I was having, although all my axis were working so I'm not sure why your Z axis isn't moving, could be voltage or it could be wiring issues or potentially a dodgy driver (try swapping it with one from another axis).

o_lampe has given some great advice and I would definitely check your voltages with the guide he as provided for you. It does sound like you 0.8vref for every stepper is a bit high unless you have quite high v steppers, my z axis runs at 0.75v now but that will be split between the two motors, all my other steppers are running at 0.35v (bare in mind I give these only as example based on the A4988 driver and are not substitutes for properly following the guide o_lampe has linked).

I am afraid I had to swap to the A4988 drivers, this sorted the problem straight away, you can sometimes hear a very high pitched noise from a stepper motor but this was also happening with my previous setup.
if you cant solve the problem with your current drivers by adjusting the voltages this would be the route I would take.
I have got some Tl Smoothers I was going to try out, If I get a chance I will swap my setup and see if the work ok, unfortunately they take a age to come from China.

Hope you manage to sort it, keep us posted.

Hey thx for the quick response

i increased the ref voltage on my z axis. now its working but sounds horible.
also i tried to turn down the rev voltages of other steppers but then my steppers lose all toque and you can turn them in the oposite direction they are running
also i forgot to mention i'm running 24v so i think the next step is the decay mode hack:24v Low Amperage Operation
When using a DRV8825 board in a 24V system, microsteps can be lost in 1/32 mode if driving a stepper with VREF <0.8v (ie a 1.5A stepper). To prevent this, connect a fine patch wire between pin 19 (DECAY) on the DRV8825 (which is N/C on the stepper driver board) to the /FAULT pin on the carrier. This will supply logic power to DECAY, and put the DRV8825 in Fast Decay mode, appropriate for 24V low amperage systems.
here is the link: A4988_vs_DRV8825_Chinese_Stepper_Driver_Boards
after that i'll play with microstepping. and if i have no luck i'll have to buy the A4988 drivers of ebay.
i'll get back around to poste my results. thx for all your help. it is appreciated.

-Sammy

Note:im awful at english sorry

edit: i also forgot to mention that the drivers defnetly are strange one of them blew up in my face see(it was hocked up correctly):


Edited 1 time(s). Last edit at 07/02/2017 06:03AM by Speatzle_.