Lights turn off, display is dead, can't be shut down but preset changes are still possible via footpedal

  • Hi,


    I own the Kemper Amp for four years now but never had this problem before: Last night during a gig the display went dead (first time greenish look with strange sings, the other times blank white) and all the lights went off. The unit couldn't be shut down normally, only by pulling out the cord. I could change the presets via footpedal (Behringer FCB normally). After restarting the unit everytime things looked ok for around 10 minutes then the lights and display showed the same problem again.


    Has anybody had the same problem and how can it be solved?:rolleyes:

  • Try turning pure cab off?

    Kemper PowerRack |Kemper Stage| Rivera 4x12 V30 cab | Yamaha DXR10 pair | UA Apollo Twin Duo | Adam A7X | Cubase DAW
    Fender Telecaster 62 re-issue chambered mahogany | Kramer! (1988 or so...) | Gibson Les Paul R7 | Fender Stratocaster HBS-1 Classic Relic Custom Shop | LTD EC-1000 Evertune | 1988 Desert Yellow JEM

  • I did, exactly the same symptoms. Front panel died due to humidity condensation inside the chassis. Sending the Kemper to Germany and £500 repair (replacement) fixed it.


    Contact support.

  • Try turning pure cab off?

    Hm I thought that was pretty funny, but it seems like I'll have to leave that out of my stand up routines for now.

    Kemper PowerRack |Kemper Stage| Rivera 4x12 V30 cab | Yamaha DXR10 pair | UA Apollo Twin Duo | Adam A7X | Cubase DAW
    Fender Telecaster 62 re-issue chambered mahogany | Kramer! (1988 or so...) | Gibson Les Paul R7 | Fender Stratocaster HBS-1 Classic Relic Custom Shop | LTD EC-1000 Evertune | 1988 Desert Yellow JEM

  • Sounds like the power supply for the Main LCD Display and the Led Driver IC's most likely a [ 7805 voltage regulator ] could be the problem.

    Considering the unit is still running leads me to believe the problem is localized. I do not have a schematic for the KPA but 7805 regulators are very commonly used for these purposes. Another cause could be that one of several of the led driver IC's that are connected to the Main LCD Display Power Supply could also be the culprit too ! If one were to fail it can pull the entire Display power supply down as a result. In that event typically the failed IC WILL BE VERY HOT TO THE TOUCH ! If you want to attempt to spare yourself the 500 euro expense. Find a local electronics repair man and demonstrate the failure to him and see if he can quickly find the issue with a little power supply probing, finger testing and logical deduction.

    Note: I do not represent Kemper nor am I affiliated other than an owner like you.

    But...... I am quite knowledgeable in digital electronics .

    Good Luck :)

  • Mr. Nightlight, Great advise if money were no object.

    Going on the premise this customer doesn't have $500.00 Euro to burn on something that a pc repairman most likely can fix within 1 hr of bench time and $10.00 in parts seems like something that makes sense to try before shipping it off and waiting .

    Here are some variables that may change your opinion.


    1. This customer has owned his KPA for over 4 years.... ding ding ding... does this tell you something ? As in can we say OUT OF WARRANTY !

    So it doesn't matter if a chimpanzee looks it over first as it makes no difference at all if it cant be fixed locally then it would need to be sent back !

    There is a good chance it can be fixed locally... IMO as being dully qualified as one whom has designed such devices.


    2. Electronically speaking there is nothing complicated or special about the design of the Kemper. It is no different than a personal computer !

    It has high quality pcb's [circuit boards ] using high quality flexible ribbon cables to connect them. One skilled in electronics and PC repair would have no problem checking power supplies and diagnosing particular IC failures even without a schematic. This isn't nuclear science ?


    But I respect your opinion ... Maybe you can pick up the tab for this guy ! Then I would have to say Kemper Fi ! Hooray for him and Fugg You !


  • Indeed, 500 pounds or euros or dollars is a really high price. If you read carefully, the user who paid that had his unit replaced. It was not a simple repair job.


    That said, have you heard of anybody who has successfully repaired a Kemper, in your humble opinion and all that? I'd be delighted to hear about it and the guy that did it for cheaper than Kemper would be greatly in demand from all of us.


    Or are you just talking out of some kind of belief or faith, iyho and all that.


    For the record, I have heard of no one, on this forum or otherwise, who has successfully had his Kemper repaired. With some manufacturers, if they spy any attempted repairs, they may refuse to repair your product thereafter.


    It is an expensive device to me. If I had to pay $500 to repair it, I would for the record.


    PS: try to be polite, or I will be far more rude than you'd like to imagine. E.g. Or are you just talking out of some kind of belief or faith, iyho and all that.


    We are just discussing this. OP will do what is necessary, I am sure.


    Edit: perhaps a mod like Kemper Support #1 or Burkhard or DonPetersen can clarify what Kemper Amps' policy is on repairing Kemper's where third party repairs have been attempted.

  • I have the same problem with my KPA. This all be the third time I have to send it in for repairs. The first two times, LEDs were out on many of kmbs. Sent it for repair, worked fora while and then more LEDs went out. Sent in for repair and came back. Now, the KPA works from anywhere from 5 minutes to 20 before the screen goes white and as the OP says, the only way to reset is pulling the AC chord out. I finally installed a Bluetooth switch so I don't have to reach behind the KPA where the AC plug is a PITA to reach.


    My unit was one from the first batch back in Feb 2012. So, slightly out of warranty.


    Has anyone got a definitive answer of what is causing this and how to repair. I'm not going to ship it again for repair.

  • I have the same problem with my KPA. This all be the third time I have to send it in for repairs. The first two times, LEDs were out on many of kmbs. Sent it for repair, worked fora while and then more LEDs went out. Sent in for repair and came back. Now, the KPA works from anywhere from 5 minutes to 20 before the screen goes white and as the OP says, the only way to reset is pulling the AC chord out. I finally installed a Bluetooth switch so I don't have to reach behind the KPA where the AC plug is a PITA to reach.


    My unit was one from the first batch back in Feb 2012. So, slightly out of warranty.


    Has anyone got a definitive answer of what is causing this and how to repair. I'm not going to ship it again for repair.


    Wow, that sucks. You should definitely contact Kemper Amps and let them know you're not happy this is happening after two repairs. Some people who I've seen on these forums haven't had issues even once despite owning their units for over five years.

  • Hey I am trying to help this guy save a few bucks and time ... That is all ... Ohh and as far as the KPA hardware is concerned there is Nothing Special !

    Its Kemper's code that is very very special !

    I'd like to correct Nightlight's disinformation about my official position as it concerns the Christoph Kempers, accomplishments.

    I challenge you to find any quote where I diminished any of Mr. Kempers awesome accomplishments specifically the KPA.

    I will admit to questioning the programming abilities and logic of the people charged with writing the control surface code and the Midi implementation which to my knowledge Christoph is not specifically one of them.

    Are you one of them????

    As a matter of fact I have much more experience in Control Surface design and coding along with specific expertise in writing efficient Midi interrupt handlers and main loop service routines !

    I can say without any doubt that there is no excuse for any Midi product these days suffering from Midi Overflow Issues or CPU Stack overflow problems.

    Sound familiar????

    For the record... and to stimulate synapses and dendrite activity in your sleeping brain.

    Christoph Kemper's profiling algorithm is nothing short of pure genius which places him in good company of the likes of Les Paul , Leo Fender , Jim Marshall and Mike Battle.

    So Kemper FI! and especially to you personally FUGG YOU!

    Edited 2 times, last by SgtPepper ().

  • Kemper has replaced whole front panel for me, not the unit. It will likely work for another 5+ years and the repair has a warranty. I didn't think they charged me too much (neither I care). Personally I don't have time to play around with unauthorized repairs which may or may not work.


    If it dies again, I'll not hesitate to replace/repair it again.


  • You're basically talking through your ass like a billion other people on the Internet.


    You show me one freaking example of someone successfully repairing a Kemper by themselves.


    I love the high and mighty attitude: "No excuse for poor coding".


    Get real, you freaking retard. Anyone can see through your freaking sham, you goddamn poser. This has been your attitude from day one.


    Maybe go tell your mother stories about your tech prowess?

  • So Kemper FI! and especially to you personally FUGG YOU!

    What's going on with this? What are you trying to accomplish here?

    But...... I am quite knowledgeable in digital electronics .

    So you say. But those who are, have no need to say except to stroke the ego. It does not give any credibility to your posts. If your advice is good, it's good. No one cares how knowledgeable you claim to be except you.


    By the way, I agree with your general advice. I think that if you're strapped for cash, and know someone capable, they could very possibly fix the KPA with little trouble. Depends on the cause of course. But this is no way to make your point.

    IMO as being dully qualified as one whom has designed such devices.

    Ok, like what? I'd love to know what you have designed. That actually would lend credibility to your posts.

    For the record... and to stimulate synapses and dendrite activity in your sleeping brain.

    Ok, at this point I'm 99% sure you have several different fedoras, and a closet full of My Little Pony shit.

    Disclaimer: When I post demo clips for profiles, there will be some minimal post-processing, unless stated otherwise. I normally double-track hard L/R, and add to the main buss a small amount of EQ and a limiter/comp set pretty light as well. Sometimes I get test profiles in advance of release, though 90% of my clips will be from packs I have purchased.

  • I love the high and mighty attitude: "No excuse for poor coding".


    Get real, you freaking retard. Anyone can see through your freaking sham, you goddamn poser. This has been your attitude from day one.


    Maybe go tell your mother stories about your tech prowess?

    Let's see some code Sarge! That'd shut this loudmouth moron up.



    And maybe nightlight would back off too. :D

    Disclaimer: When I post demo clips for profiles, there will be some minimal post-processing, unless stated otherwise. I normally double-track hard L/R, and add to the main buss a small amount of EQ and a limiter/comp set pretty light as well. Sometimes I get test profiles in advance of release, though 90% of my clips will be from packs I have purchased.