bamboscha Posted July 5, 2021 Share Posted July 5, 2021 Hi all, I'm having some problems with my Little Mark III. It's an Italian made one from 2013. I know the proper thing to do would be to send it off to that place in Sheffield that do the Markbass servicing, but I thought I'd call upon the collective genius of BC just to try to get an idea of what's going on. So here's what I know..... It's making hissing/crackling/popping noises. Left long enough, these develop into a loud, sustained, high-pitched scream. It's rather unpleasant. The problem is intermittent. I switched it on yesterday and left it on for a few hours and the problem did not arise. Today, I switched it on again and within 10 minutes, the noises began. The noise happens regardless of the position of the gain and master knobs, even both off - I don't think it's a dirty pot issue. It's definitely the amp, not the cab, as it's done it with two different cabs. It's not the power in my house. It's done it to me on a gig. A very posh hotel gig, in a room full of millionaires, halfway through The Girl From Ipanema. Very embarassing. As I mentioned above, it's at it again today. So I did the only thing I haven't yet tried - turned it off, disconnected the speakon to speakon cable, reconnected with a jack to speakon and turned it back on. It's been fine for the last half hour. Anyone had similar problems? I'm guessing if it's something on the main board then it's going to be an uneconomical repair. Is it destined for the bin? Quote Link to comment Share on other sites More sharing options...
BassBunny Posted July 5, 2021 Share Posted July 5, 2021 I guess you may have answered your own question in that the possible answer is a faulty speakon socket on the amp or a faulty cable, which I' m not sure that's likely. The other thing to try is shoving a jack plug in and out of the effects loop jack sockets. A squirt of switch cleaner on the jack plug could help. Sending to Real Electronics will likely cost to £200+. I can give you the full charges if you want them. A decent amp tech should be able to change the speakon, if that does turn out to be the problem. If you can leave it on using the jack output for the equivalent of a gig should confirm one way or another. Quote Link to comment Share on other sites More sharing options...
bamboscha Posted July 5, 2021 Author Share Posted July 5, 2021 @BassBunny thanks for the reply. By all means PM me the charges, I'd be interested to know. 3 hours later it's still fine coming out of the jack socket, although yesterday I had it on for at least two hours, probably more, coming out of the speakon and it was also fine. Having said that, it's always been difficult to get the speakon to lock in properly so maybe it IS a faulty socket. I've owned it from new and looked after it very well. I'm not bad at soldering, I reckon I could fit a new speakon socket myself. Now, which bits of the amp is it I'm not supposed to touch in order to not kill myself?? 😂 Quote Link to comment Share on other sites More sharing options...
BassBunny Posted July 5, 2021 Share Posted July 5, 2021 Intermittent faults are the worst in the world to diagnose and what you have said about it running for 2 hours using Speakon, it might not be cut and dried. Try the effects loop trick first and then test again with the Speakon. The effects sockets are renowned for oxidising causing all sort of weird faults. The costs from Real are £35 to diagnose the problem, which you get back if you go ahead. £69 fixed labour, £18 courier fee to send it back + parts + VAT. I am pretty sure they don't repair to component level. I was quoted £150 for a main amp board for an SA450 which would have made it an uneconomical repair, so I didn't bother. 1 Quote Link to comment Share on other sites More sharing options...
Bigguy2017 Posted July 5, 2021 Share Posted July 5, 2021 As suggested clean the FX send + return jacks. It sounds more like a intermittent dry joint coming and going with warm up Do a thorough visual inspection looking for bad soldering, leaking or domed capacitors, loose connectors etc. To localise, try powering it on with the cover off and tapping / poking with a wooden chop stick. Tap the components and connectors. Flex the PCB. If you do reproduce the fault then reflow the solder joints in that area. 1 1 Quote Link to comment Share on other sites More sharing options...
Jakester Posted July 6, 2021 Share Posted July 6, 2021 17 hours ago, BassBunny said: Intermittent faults are the worst in the world to diagnose and what you have said about it running for 2 hours using Speakon, it might not be cut and dried. Yep. After trying everything for a weird volume issue that had been going on for years, I sent my Combo Amp II (basically a LMIII) to Real. They couldn't find anything wrong with it. As a precaution I agreed to all the pots being replaced as they said there wasn't anything else it could have been. Used it twice since then so I'm hoping that cured it.. a pretty expensive trip if not! 1 Quote Link to comment Share on other sites More sharing options...
bamboscha Posted July 8, 2021 Author Share Posted July 8, 2021 Thanks again for the advice guys. On Tuesday I flicked it on again, still coming out of the jack output and within 10 minutes it began with the interference-style noises, so at least I can rule out the Speakon socket. My next step is to try the fx loop as you suggested, but I'd really like to do it while it's making the noise so I can see if there's an audible effect when I link the send and return sockets. Trouble is it stopped doing it before I could lay my hands on a cable. I've had it on for hours yesterday and today and it's been fine. Bloody thing! Quote Link to comment Share on other sites More sharing options...
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