October 25, 2012

Kenwood Chef speed control problem


Symptoms:
Speed control is not working, it would go from Stop to Full Power once turned on.


To gain access to electronic module, flip the unit and remove the lever locking mechanism.



Mark the cable position so that you do not forget, and unplug.

















Remove clips on the white cover and gain access to the electronic module. It is quite simple and the likely issue is the TRIAC. Order and replace this.

The TRIAC is BTA208-600B. I bought mine from x-on.com.au. They are only $1 each and I bought 3 of them as spare, shipped for $20 to Melbourne.

Link: Triac BTA208-600B

Once replaced, the speed control works properly :)





16 comments:

  1. Thank you very much for this detailled description.
    my kenwood is the same as yours (kenwood chef km300)
    My problem was a little bit different, as the speed control worked but only from 50% to 100%. from start to 50% on the knob, i would have 50% power.
    I did change the Triac as on your drawing, then another capacity. and finally I tested all resistance, and it was R3 (470khoms) that was dead.
    changed it and worked fine.

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  2. KM300 when switched on went up to full speed and then reduced to a crawl.
    Speed board changed but no difference.
    When starting to remove motor for inspection I noticed that one of the very fine wires on the smallest plug on the speed card had broken, it looked as though it had been trapped. I reconnected with a fine solder joint and heatshrink cover, replaced all parts and mixer then worked fine.
    I think these two fine wires (white) must go to some sort of speed sensor under the end cover of the motor.

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    Replies
    1. Thanks! In my case the wires were intact but the feedback sensor at the end of them was not working properly due to the fan becoming dislodged. My answer is below.

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  3. Hi, I've got the same problem as you with my kenwood major titanium. Therefore I ordered the TRIAC is BTA208-600B, after arrival I replaced it with the old one but it still doesn't work. Can you perhaps help me or give me alternative options how I could fix it? Can I perhaps contact you to give more information if needed?

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  4. Ours is ok until you get to setting 4 afterwards you cannot make it go faster on a higher setting

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  5. All I want to do is change all the plastic parts from one kenwood chef to another, I can manage everything except the speed control. How do I do it???!!!

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  6. This comment has been removed by the author.

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  7. Try the following if the triac alone doesn't fix the issue, in addition to the Triac, replace the following... 2 x 4.7K 2W metal film resistors (the two large resistors to the left of the above picture), and the 16V 220uf Cap (substitute a 220uf 25V).

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    Replies
    1. Good day to you sir,
      Do you happen to have a link to where I could purchase said resistors? I am unable to find them using your description alone on the internet...

      Thanks in advance..

      Delete
  8. This works great. I actually repaired a Kenwood Chef KM001 with it. The actual TRIAC part number is different in the KM001 - it is BTB16 - 600CW - but since i had already ordered the BTA208 as mentioned above it tought I would stick it in an see how it went. Works perfectly for the moment! Slightly different way to get to the circuit board: Lift the top of the machine open as during normal use, turn it on its side and look for 2 screws very deep up in the back. Get these screws out (strangely one was a phillips head and one a star screw..... ) then stand it up and remove the sharp pin which is part of the locking mechanism. Pull the plastic cover downwards to reveal the motor. Disconnect the 3 electric connections, gently bull down on the speed control knob to remove the assembly. Find the triac, break it off the 3 pins and then unsolder the pins. Bend the new triac arms to suit, solder in and reassemble! Thanks again to all the gurus out there.

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  9. Thanks for posting this! TRIAC replacement on my KM330 solved my speed problem- although I did have to have two shots because my first soldering was not great!

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  10. Good day to you sir,
    Do you happen to have a link to where I could purchase said resistors? I am unable to find them using your description alone on the internet...

    Thanks in advance..

    ReplyDelete
  11. you could also try a BT137600E TRIAC. This Triac worked perfectly on my Kenwood Chef KM 210 speed control. Also replaced the 0.1uF Capacitor. The PH 71719 (m8732) triac is unobtainable.

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  12. hi, kenwood km001, no low speed ; changed triac and 220uf condenser although the later tested ok; resistors test ok and so x2 anti spark filter; any suggestions will be appreciated

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  13. Hi...am having a steady speed issue on my KM800 Kenwood Mixer. The speed simply fluctuate without adjusting the speed knob. It sometimes went up to maximum which makes all the ingredients in the bowl flying!!!! I have surveyed almost all electronic shops but to no avail. Can you suggest me the equivalent Triac which is also compatible?

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  14. Hi there I have a KM331 with what I think might be this very problem would the layout be the same? And would an one know the best way to get into the gearbox so I can replace one of the gears or is this a specialist job?

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