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Carvin MB210 sound cuts in and out when powered up

Discussion in 'Amps and Cabs [BG]' started by Dr_Benway, Oct 11, 2018.


  1. Dr_Benway

    Dr_Benway

    Aug 22, 2018
    Earth
    I have a Carvin MB210 with a 210 extension cab. I love the sound of this thing. I've had it for about two years now. A few months ago i powered it up and there was very little sound. It sounded like it was compressed to death. After fiddling with the knobs a bit it would cut back in with a loud pop and work.

    I heard somewhere that it could be the input jack getting dirty. Sometimes unplugging and plugging a cable back in will make it work. It seems not to be a problem once the amp warms up.

    It seems to happen every time I power it up.

    I can't find anything on the internet about this problem and Carvin is out of business. I love the way this amp sounds so any help would be greatly appreciated.

    thanks in advance
     
  2. sissy kathy

    sissy kathy Back to Bass-ics Gold Supporting Member

    Apr 21, 2014
    Arbutus, MD
    Last edited: Oct 11, 2018
  3. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    Let me correct you here... the Carvin that built his amp no longer services or provides warranty work on amps they built. In their words, they shut down and let everybody go (including all of their parts).

    The "new" Carvin does not repair the "old" Carvin's equipment. I have a customer who tried to receive warranty service and received the "pound sand" response. This is a very, very good customer of mine, so I took care of him because it was the right thing to do even though I didn't make a penny on the original sale, though he did buy me a nice lunch. Fortunately, it was something that I could repair and had parts for, but that was simply his good luck.

    If anybody has Carvin amps or PA gear (in the US) that needs service, I tried and was unable to find anybody willing (or able) to work on his amp. This might be a good business opportunity for one of the resident (qualified) techs on TB.
     
  4. sissy kathy

    sissy kathy Back to Bass-ics Gold Supporting Member

    Apr 21, 2014
    Arbutus, MD
    Dr_Benway and Mushroo like this.
  5. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    While I appreciate your attempt to help, I think you will find the experience more difficult than you think. The more you know, the more you will appreciate my comments.
     
  6. sissy kathy

    sissy kathy Back to Bass-ics Gold Supporting Member

    Apr 21, 2014
    Arbutus, MD
    I don't know anything about any amp, just trying to help someone in need. I don't know if the OP had a schematic before, but he does now.
     
    Last edited: Oct 11, 2018
    Dr_Benway likes this.
  7. Dr_Benway

    Dr_Benway

    Aug 22, 2018
    Earth
    Thank you very much. I have a feeling it might just be dirt in the input, because pulling the cable out and reinserting it seems to fix it and it doesn't happen again until I restart.

    Thanks again!
     
  8. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    Probably not, because the act of inserting the cable would clean the contacts without doubt.

    There is an intermittent connection, the problem is identifying where it is. Since the amp does not contain an effects loop (the most common cause of this symptom), you are left with the other 1,000 (or so) connections to contend with. If you have test equipment and understood how the amp worked, you might have a chance but there are places within this amp that are not easy to diagnose even if you know what you are doing (especially without a PCB map).

    In general, it takes somebody very familiar and experienced with the amp to efficiently diagnose (correctly) and repair, It's easy to diagnose incorrectly, it's done on the internet (and TB) all the time, but incorrect diagnosis is the key to starvation as a service tech.
     
  9. Dr_Benway

    Dr_Benway

    Aug 22, 2018
    Earth
    I get that. And thanks for the advice. I'm checking around town this week to see if I can locate a competent service tech. I've also read about problems with the ribbon cables in this amp.

    It's really quite strange. When I power it up, half the time I get no sound at all until I unplug the cable and re-insert it. Usually I have to do this a few times. It will start to work then crap out. By crap out, I mean it pops then gets real quiet (like the compressor is on full). It sounds quiet and distorted, then if I insert a cable again it starts working. Strange stuff.

    I found an MB10 at a guitar center that I might pick up to have as a spare, in case it's out in the shop for long. Never hurts.

    Thanks again.
     
  10. johnson79

    johnson79

    Jan 8, 2010
    Lancaster, PA
    I had an issue with my GK 400RB cutting out. I narrowed it down to the input jack. I cleaned it and tightened the contacts, but the problem persisted. I quickly realized that it would cut out when I played loud, so I ended up resoldering the connections on the PCB and it's been working 100%. Not saying that's the solution to your issue, but hopefully, your fix is as simple as mine was.
     
    dBChad and Dr_Benway like this.
  11. Dr_Benway

    Dr_Benway

    Aug 22, 2018
    Earth
    Well... i just opened it up and checked all the connections. A few were loose. I put it back together and turned it back on and everything seems to be working again. We'll see what happens. I'm still getting a backup, that I can drop in, if there is another problem.

    Thanks for all your help!
     
    dBChad and johnson79 like this.
  12. sissy kathy

    sissy kathy Back to Bass-ics Gold Supporting Member

    Apr 21, 2014
    Arbutus, MD
    Really? You have a Carvin with problems, that Carvin won't service, and you're thinking of getting another one? They would have to be giving it away for me to get a Carvin at this point.
     
    S-Bigbottom, agedhorse and Mushroo like this.
  13. BassmanPaul

    BassmanPaul Gold Supporting Member

    Aug 25, 2007
    Toronto Ontario Canada
    Sadly I would have to agree and most of the equipment I use came from Carvin.
     
    Bassist4Eris likes this.
  14. BadExample

    BadExample

    Jan 21, 2016
    Injiana
    Internal connections seem to be the archilles heel of Carvin.

    Those schematics give me a headache.
     
    Plucky The Bassist likes this.
  15. kpc

    kpc

    Apr 6, 2011
    I would check the multi pin plug-ins inside (if any). That seemed to be Carvins miss. I had to de-ox-it on my bx500. Never had a problem since.
     
    gitfiddl, Dr_Benway and rwkeating like this.
  16. Dr_Benway

    Dr_Benway

    Aug 22, 2018
    Earth
    Thanks. That's what I did when I opened it up. I've tried it four times without a hitch so far. If it happens again, I'll grab the de-ox-it! Thanks for the tip!
     
  17. KickingBass

    KickingBass Look into it

    I had a similar problem with a Carvin. I eventually was able to sell it to someone on here who was willing to deal with the problem. The problem was with the internal ribbon cables being dirty. I am currently having a similar problem with my Tech21 VT500 and it breaks my heart because that amp is amazing. It will be fine and then suddenly the sound cuts out of my speakers (though not the DI) and then come back after a few seconds. Anyways, check the ribbon cables for corrosion if you can. I would clean mine periodically and it would help but it was too much of a hassle.
     
    Dr_Benway likes this.
  18. iiipopes

    iiipopes Supporting Member

    May 4, 2009
    I gig with an MB-12. Have for quite a few years now. Same amp, different speaker configuration. This doesn't sound good. I had the same issue a few years ago. The delay circuit that supposedly internally checks the amp and keeps the amp from shorting out as it powers up may be bad. I would contact the company and see if in spite of discontinuing the amp/pa side of the business, if they still do repairs.
     
  19. cheechi

    cheechi

    Mar 10, 2015
    I have vintage Ampegs that Ampeg won't service, vintage Peaveys that Peavey won't service, and now I guess you could call them 'vintage' Carvins that Carvin won't service. Granted with the first two it's much easier to find a competent tech if it's outside my ability.

    Warranty doesn't give me more confidence in a product that's proven in the real world, it's there to give confidence in the company. The new Carvin isn't winning any awards for customer confidence but that doesn't magically mean that the good products made by the old Carvin are suddenly garbage.
     
    Dr_Benway likes this.
  20. sissy kathy

    sissy kathy Back to Bass-ics Gold Supporting Member

    Apr 21, 2014
    Arbutus, MD
    I'm not suggesting they are garbaqe. My knowledge of amplifier repair stops at the fuse. If I can't get an amp fixed when it needs repair, I don't want it.
     

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