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Soundcraft Signature 12 MTK Power Supply down (need electronic layout of power supply)

My Mixing console can't power on.

I Open it, and see that one Resistor (R102) et one Condensator are down.

I need the right reference for the resistor (R102), i already change the condensator (100microfarad25v).
I can't determine the right colors fot the resistor. (it's 10ohms or not ???)

So i search the "schéma structurel du circuit imprimé" (electronic layout of the printed circuit board of the power supply".
So i could found the good information about this resistor.

I hope i can fixe this failure.

Sorry for my porr english.

Thanks for your help.




  • alxlucalxluc Posts: 5

    HELP PLEASE !!! Just need the reference of the resistor engraved on integrated circuit: R102 ! (10 ohm ?)
    Thank you.

  • Hello A.L, please contact your local Harman Pro Tech Support for this issue. Or, if you could post a picture of the resistor, the community may be able to help you further.

  • Hi, Thanks you for the answer.

    I ve got these pictures

    1550591324-20190129-150538.jpg - envoi d'image avec NoelShack
    1550591324-r102-1.jpg - envoi d'image avec NoelShack
    1550591324-r102-2.jpg - envoi d'image avec NoelShack

  • If someone could help me or send me the picture of his own power suplly.
    i already change the capacitor.

    I need the right ref of the resistor's colors indication

    • brown / black (?) / brown or gold (?) / Gold
      100 Ohms 5%

    • Brown / black (?) / gold (?) / gold
      1 Ohms 5%

    • Brown / Black(?) / red (?) / gold
      1k Ohms 5%

    I would swap the resistor and test the power supply before calling assistance.

    Thanks you.


  • alxlucalxluc Posts: 5


    You lost a client .

    I fix it... without soundcraft support...

    I never buy another product from your company,

    and won't provide positive publicity.


  • Hey Alxluc,

    i'm having the exact same problem! Could you tell me the details of both parts so I can also make the repair?
    Many thanks!

  • FergFerg Posts: 1

    Hi AL

    I have a Soundcraft signature 12 which is barely a year old and was working fine but now fails to power on , so very interested in your post and your solution any more details available ? re what parts I might need, and if a relative newbie could make this repair

  • My MTK 22 only has 30 hours of usage. R102 is already looking very BBQ. It looks like a 2W 75K carbon, though the purple stripe is almost indistinguishable from brown. My mixer still works and that resistor measures >60k so I think 75k is right. Put four of these back in series/parallel or a larger wattage part.

  • I can confirm it is 75k now that I pulled it out of the circuit. I'll be using two 150k in parallel.

  • alex69alex69 Posts: 2
    Same thing happened to me too.I did contact the soundcraft service at my country ( Greece) and the answer i got is that i have to buy a new power supply (the whole system there) for 100 euro.I am very disappointed and angry with this.
  • hanchhanch Posts: 1

    Just having the same issues with Signature 12.
    @HARMAN_Rob, Since you're the only one from Harman that responded here, is there any response from HQ about this plague?
    So many devices fail on their first year?
    No response from the Support team in the forum?
    Local No assistance from the support team on how to solve it but just buy new modules for almost half the price of a device?


  • AnustusAnustus Posts: 1

    Exact same problem as set_aus.
    Now fixed thanks to this thread.

  • I have the same issue, can't seem source 2w resistors in Australia, any help on sourcing would be appreciated.

  • SweekoSweeko Posts: 1
    edited May 2020

    I own the 12 MTK since 4 years now. The issue was fixed by the manufacture in 2018 officially. 2020... and here we are again, same issue with the Power supply. Thanks for this thread i saved 2 or more weeks and money. Just use 4x 1/2 W 75k resistors soldered in parralel as writen above. I did not change the cappacitor. Works again like at day one.

  • mmmotionmmmotion Posts: 1

    My MTK 12 started whining from the power transformer :(
    One capacitor was also bulging so I hoped that was the cause, but after replacing it, the whine/squeal is still there.

    Any ideas? Part numbers?

  • damirs_mnedamirs_mne Posts: 6

    I'm having the same problem. The resistor is little burned but multimeter reads 75kOhm.Also, multimeter reads 320 volts on primary but nothing on secondary. I get the transformer out from circuit and there is no open circuit on secondary windings. Please help, no service here can fix it and the shipping don't work because of COVID :( so I'm on my own... I will post more info if you have will to help me.

  • damirs_mnedamirs_mne Posts: 6

    I fix it myself guys. The problem was with two caps near the 74kOhm resistor.

  • Djefx01Djefx01 Posts: 1

    Hi damirs_mne, can you give some details on how you fix your mixer?

    Thank You,

  • Just replace caps near that resistor. They probably fail because of the heat coming from 74k resistor
  • yardenakyardenak Posts: 3
    Having the same problem here.
    Can you tell me which one you changed? Everyone seems fine.
  • @yardenak visualy they look like new but their failed... Alxluc marked the resistor near them so look at his post to find them...
  • yardenakyardenak Posts: 3
    Changed the 75k, 10uf, 100uf, and it’s working!!

    You guy’s are the best!
    Harman, you sucks!
  • @yardenak I'm glad to hear that ;)
  • Never again buying a Soundcraft/Harman product. Support your flawed products and issue replacement power supplies at no cost.

  • SandvikSandvik Posts: 1

    Seems I have the same issue as you guys. Is it completely confirmed that R102 is a 2w 75k ohm resistor?

  • yardenakyardenak Posts: 3
    edited August 2020
    Yes :)
    I’ve put a 82k with 10% and it’s work great :)
  • I only replaced caps near it,not resistor
  • appolloappollo Posts: 1

    hello the color code of the r102 @yardenak is it gray red black silver ? it works well ?

  • martinomartino Posts: 2

    Hi all, my Soundcraft MTK-22 has stopped powering up properly - when it is turned on, the consoles' FX panel and LEDS all flash continuously and the console puts out a clicking noise.

    Youtube video here - https://youtu.be/xN9MWL0lRgI

    Is a replacement power supply what I need here? Are they user replaceable?

    Any input appreciated!

  • Having the same problems here too, completely dead mixer, initially when i turned on from the socket it took between 5/10 minutes to come alive which gradually got longer to the point where now it won't do anything, desk is only two years old, opened it up and can see that r102 looks fried, all the other resistors look fine so not sure if its just r102 needs replacing or not, capacitors all look fine from what i can see but again i'm not expert so hard to know. Still can't believe this desk never had a simple on/off switch.

    Could anyone point me in the right direction for the correct resistor to replace r102? Have trawled the net / mouser etc but can't seem to find exact match and don't want to take a chance with a wrong resistor.

    Many thanks

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