Vibrating G String Posted October 15, 2011 Share Posted October 15, 2011 Hi, I was playing at a gig through my trusty LMII and to hear one cabinet soloed I pulled a speaker cable from the back of the amp while I was playing and plugged it back in. Shortly after that the amp was dead quiet though signal was still flowing out the DI in back and into the PA but not to either cabinet. I futzed with it a bit and then after turning it off and back on it worked again. Is there some kind of circuit breaker/protector in there that I tripped or might I have more serious problems? Quote Link to comment Share on other sites More sharing options...
Pete Academy Posted October 15, 2011 Share Posted October 15, 2011 Are you using jacks or speakons? Quote Link to comment Share on other sites More sharing options...
chrismuzz Posted October 15, 2011 Share Posted October 15, 2011 I've never experienced that.. But once I put my F1 through a cab that didn't have a high enough power handling... As luck would have it, the fan hadn't come on on the head (an intermittent problem on F1s I think, easily fixed by blowing into the hole to get it moving ). Which meant it was running a bit hot, and shut itself off. I turned it off and on and was fine. So it's probably a thermal protection type thing Quote Link to comment Share on other sites More sharing options...
pete.young Posted October 15, 2011 Share Posted October 15, 2011 [quote name='Vibrating G String' timestamp='1318669031' post='1404898'] I futzed with it a bit and then after turning it off and back on it worked again. Is there some kind of circuit breaker/protector in there that I tripped or might I have more serious problems? [/quote] Yes - there is protection circuitry which cuts out the power stage if the amp overheats or the power fluctuates - I'd say that you have most likely triggered this by unplugging and plugging stuff in with the power on. As you've found out, it's generally not a good idea to connect and disconnect speakers from amps with the power switched on. Quote Link to comment Share on other sites More sharing options...
Vibrating G String Posted October 18, 2011 Author Share Posted October 18, 2011 [quote name='Pete Academy' timestamp='1318669247' post='1404904'] Are you using jacks or speakons? [/quote] Hi, I was out of town for a few days sorry for leaving you hanging. I used jacks. Quote Link to comment Share on other sites More sharing options...
Vibrating G String Posted October 18, 2011 Author Share Posted October 18, 2011 [quote name='pete.young' timestamp='1318674368' post='1405004'] Yes - there is protection circuitry which cuts out the power stage if the amp overheats or the power fluctuates - I'd say that you have most likely triggered this by unplugging and plugging stuff in with the power on. As you've found out, it's generally not a good idea to connect and disconnect speakers from amps with the power switched on. [/quote] Thanks, that's what I was hoping to hear. Quote Link to comment Share on other sites More sharing options...
Vibrating G String Posted October 18, 2011 Author Share Posted October 18, 2011 [quote name='chrismuzz' timestamp='1318670322' post='1404921'] I've never experienced that.. But once I put my F1 through a cab that didn't have a high enough power handling... As luck would have it, the fan hadn't come on on the head (an intermittent problem on F1s I think, easily fixed by blowing into the hole to get it moving ). Which meant it was running a bit hot, and shut itself off. I turned it off and on and was fine. So it's probably a thermal protection type thing [/quote] I've heard a number of complaints about bad fans on MarkBass amps. They look like standard computer type fans, I'd bet there's a higher quality model we can swap in. It's a great amp at a great price and putting a few dollars into modding it would be reasonable for me. Quote Link to comment Share on other sites More sharing options...
Linus27 Posted October 18, 2011 Share Posted October 18, 2011 I have had this happen to my MarkBass combo. Quote Link to comment Share on other sites More sharing options...
chrismuzz Posted October 18, 2011 Share Posted October 18, 2011 The only issue I have with my fan is that I have to take a few seconds to check it's on. If it's not, I blow into it to get it going. Did consider sending it back when I discovered the issue a few months after purchase but I didn't want to let go of it as being without it for x amount of time wasn't worth it Quote Link to comment Share on other sites More sharing options...
Pete Academy Posted October 19, 2011 Share Posted October 19, 2011 [quote name='Vibrating G String' timestamp='1318972373' post='1408541'] Hi, I was out of town for a few days sorry for leaving you hanging. I used jacks. [/quote] My mate had problems with a MB speaker cab. Turns out there was a minor problem with the speaker jack. Might be worth trying speakons. Quote Link to comment Share on other sites More sharing options...
Monckyman Posted October 19, 2011 Share Posted October 19, 2011 I`ve done this while hot-swapping cabs on my LM 2. It`s a normal protection feature. Just reboot the amp. As to the fans, they are standard computer issue and they can be replaced with silent running ones in under 20 minutes and for a few pounds/dollars. MM Quote Link to comment Share on other sites More sharing options...
Linus27 Posted October 19, 2011 Share Posted October 19, 2011 Thanks Monckyman Quote Link to comment Share on other sites More sharing options...
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