iRobot Roomba 800 Clicking noise when docked FIX

Written By: jenkie
  • Comments: 12
iRobot Roomba 800 Clicking noise when docked FIX

Difficulty

Moderate

Steps

5

Time Required

20 minutes

Introduction

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    • First check, if this fix applies to you: Remove the vacuum bin and listen if the clicking noise has vanished. If so, this fix will help you

    • The source of the clicking noise are voltage spikes (1-2 milliseconds duration) which are sent to the vacuum bin motor, giving it a short, hearable kick. We will add a soft-start functionality to the vacuum bin motor such that those spikes will have no effect.

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    • Parts you need:

    • one n-FET (I used BUK663) but any n-FET with a voltage rating > 20V , a current rating >10A and a gate-source threshold voltage Vgs<5V should work

    • Two 100kOhm resistors

    • one 10 µF/25V capacitor (careful, has positive and negative side!)

    • Solder everything together according to the schematic

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    • Open the lid of the vacuum bin by removing the four silver screws and carefully remove the lid

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    • Cut the black wire and insert the circuit. Do not forget some large shrinking tube to cover the whole circuit later (not pictured)

    • Add a wire between the gray-wired connection tab and the resistor R2 (white wire in the picture). Add some shrinking tube to the resistor to prevent short-circuits.

    • WARNING: Do not solder the wires when the connection tabs are in the plastic holder - the plastic will melt. Remove the contacts from the plastic before soldering

    • Shrink tube over the whole circuit.

    • You can test the circuit with a 12V or 9V battery/voltage supply. Positive voltage is the grey-cabled tab, negative the black-cabled one. The motor should start with a short delay (1s or so)

    • Reassemble vacuum bin and enjoy the silence.

Conclusion

To reassemble your device, follow these instructions in reverse order.

Author

jenkie

Member since: 12/02/17

366 Reputation

12 comments

This 100% correctly identified my issue with continuous clicking coming from the filter fan. I will add that this happened on my unit even when it was removed from the charger and powered off. However the soft start circuit you created did not work for me. This may be due to incorrect wiring or using the wrong components, but I believe I followed both to the best of my ability. The mosfet I used is the STU13N65M2 n-channel MOSFET (which I believe matches the minimal specs you provided.) Panasonic 10uF 50v caps, and nice 1W 100K ohm resistors. No dice…

Jason Benguerel -

I just checked the specs of that MOSFET, and it differed from the website where I bought it. The Vgs is ~25 volts, so that’s probably where I went wrong. I will update with a working part number if I can find one.

Jason Benguerel -

After further experimentation I discovered I was not correctly identifying the MOSFET pinout and it was miswired. By looking at your physical example I was able to see what I was doing wrong. Maybe add a clearer indication of the MOSFET’s pinout on the schematic if you have a chance.

Jason Benguerel -

Is it working now? It is important that you have a FET with Vgs <= 5V.

jenkie -

Thanks for this fix ! I’m planning to try it in the next few days, this clicking noise is really annoying. And since my Roomba’s dock is next to my computer, I was convinced that the noise was coming from one of my hard drives ! An old broken hard drive of mine made the same kind of noise.

Just one question : the capacitor on the picture is a 10µF/63V, but you say a 10µF/25V is ok in the instructions… which one should I take ? By chance I found the exact same MOSFET in my local store, so no issues on this side.

Michael Magi -

25V is perfectly fine, this value gives you which voltage the capacitor can withstand. Since there are no voltages above 20V in the roomba you are safe with a 25V capacitor.

jenkie -

Thanks works like a charm.

I want to share my experience as it might help others.

Component Details

For the reference I used a RFP12N10L MOSFET instead. Link

The capacitor in the description is described with 25V but it only a minimum supported voltage, the one I used was a 10uF/50V capacitor.

Issues

I ended up connecting it with reversed polarity the first time which burned the MOSFET (internal resistance went from 0,5 ohm to 50 ohm Gate->Drain) this results in the engine not getting enough power and sound wired worked perfectly on the second try though.

It was either the reversed polarity or a too hot soldering iron, I found in the datasheet for the MOSFET that it only could withstand 300 C.

Good luck to anyone trying this.

I kinda skipped contacting support about this, if any one did and had any luck that might be worth sharing as well…

Stefan -

Thanks, worked perfectly!

Now it´s silent at night

C. Johansson -

Great fix man! I made this PCB, tried yesterday and seems to work fine! https://aisler.net/p/XPLBGGHX

Matteo -

Thanks for the effort of making a PCB! The fix is working in my Roomba now for almost 2 years, absolutely no problems.

jenkie -

Great work Jenkie. I just assembled it and it no sounds so far. I used different MOSFTE - BUZ11, that has higher threshold voltage, so I decreased R2 to 10k, but increased the cap to 100uF. Thanks :)

Georgi Nikolov -

Awesome fix! After working from home the last two years, the clicking has been driving my crazy. I finally tracked it down to my Roomba, and this fix has stopped the clicking. The last week has been gloriously click-free.

Aaron Caba -