thumbo Posted June 17, 2008 Share Posted June 17, 2008 Earlier this evening I was switching my Markbass TA503 between 2 different cabs to hear the difference in them. I was being very careful with turning the amp off before taking out any speaker cables but it seems that all this switching it on and off has caused a problem. When I turn the amp on now, no lights come up on the front, I can hear and feel the fans spinning but it's not outputting anything. I think this is something to do with a protection circuit but I can't be sure. I know that these amps don't really go wrong so I've been struggling to find any troubleshooting or info online. I've emailed Mark Bass to explain the issue. Any thoughts? Thanks Quote Link to comment Share on other sites More sharing options...
Basszilla Posted June 18, 2008 Share Posted June 18, 2008 I had the protection circuit go on my MB amp before. It was as a result of a very long jam in a very warm room with poor ventilation. By the time I got home and let it cool down it worked fine much to my suprise. That's the only hiccup i've ever had. Quote Link to comment Share on other sites More sharing options...
thumbo Posted June 18, 2008 Author Share Posted June 18, 2008 (edited) I had that happen once with my old LMK, it just cut out for a while to cool itself down then worked fine again after about 20 minutes. I thought that my TA503 had done that but unfortunately it hasn't switched back on since :-( I just hear the fans spinning away. I'm pretty gutted because I've only just got my Bergantino cab. Markbass weren't much help they said that "it's impossible to diagnose a problem through email". Edited June 18, 2008 by thumbo Quote Link to comment Share on other sites More sharing options...
BOD2 Posted June 18, 2008 Share Posted June 18, 2008 Fuses ? Since the fans are spinning the fuse in the mains plug is OK. If there's a fuse below where the mains lead plugs in then this is probably OK too (although it would depend on it'e exact location in the circuit). Are there any internal fuses that can be replaced by the user ? Quote Link to comment Share on other sites More sharing options...
thumbo Posted June 18, 2008 Author Share Posted June 18, 2008 Hi Bod, I've checked the fuse just below where the mains lead plugs in and it's fine. I have been wondering about internal fuses. I'll have to research this a bit more. Quote Link to comment Share on other sites More sharing options...
thumbo Posted June 18, 2008 Author Share Posted June 18, 2008 (edited) I've just had a good look through the manual again, no mention of internal fuses but it's not exactly the most detailed manual in the world. No troubleshooting or anything in there. Edited June 18, 2008 by thumbo Quote Link to comment Share on other sites More sharing options...
BOD2 Posted June 18, 2008 Share Posted June 18, 2008 How easy is it to open it up and have a quick look ? Any fuses should be fairly obvious and if they're glass-bodied you can tell if they've blown easily enough. A quick visual check of any connectors inside the amp wouldn't do any harm either. Also, doesn't that amp have a preamp valve inside ? If so then it might be worth reseating that in its socket. Quote Link to comment Share on other sites More sharing options...
thumbo Posted June 18, 2008 Author Share Posted June 18, 2008 It should be quite easy to have a glance inside it. It's been living in a rack since the day I got it but if I remember rightly there's just a panel on top of Mark Bass amps that can be easily unscrewed and lifted off. I'll have a glance over the connectors tonight, there's 2 pre-amp valves in it I think so I guess there's no harm in reseating them to see if that's the issue. Thanks Quote Link to comment Share on other sites More sharing options...
thumbo Posted July 2, 2008 Author Share Posted July 2, 2008 I have just got this amp back from Proel (mark bass distributor), it had to have it's "power block replaced". I don't know what that means but that's what it says on the repair report. Thankfully it was under warranty as all Mark Bass amps have a 2 year warranty. Now, I must give it a thrashing with my Berg NV610!! Quote Link to comment Share on other sites More sharing options...
Sugden Posted July 2, 2008 Share Posted July 2, 2008 Markbass major problem seems to be their power blocks everytime I hear about one going wrong its the power block. Might be me though my LMKII went back for it to be replaced as well. Tell you what though I had to talk to alot of people before they admitted it was covered by a 2 year warranty for markbass, obviously they have started reading the warranty cards they send out with the amps they sell. But they do a fantastic service got my amp in 2 and a half weeks with xmas slap bang in the middle. Plus the maddest thing is they call you back when they say they will Quote Link to comment Share on other sites More sharing options...
Basszilla Posted July 30, 2008 Share Posted July 30, 2008 (edited) I managed to kill my MB amp last night. The sound went but the power light stayed on. 5 mins later it's almost bursting into flames. Smoke shooting out of the vents like nobodies business ha ha. Thing was, I never drive it to clipping point and I don't really push the power section 'that' hard either!!! Oh well, it was good while it lasted. It's only 3 years old though I wouldn've thought it'd last a lot longer than that. I'm wondering if there's any point at all in contacting Proel/MB about it. Edit: I took it apart to see what had happened and I'd done some serious damage to the PCB, talk about chargrilled!!! Loads of components had melted etc... I took a series of photos of the innards, so i'll email them to MB at some point and ask them about their supposed miniscule component failure rate. Edited July 30, 2008 by Basszilla Quote Link to comment Share on other sites More sharing options...
yorks5stringer Posted July 30, 2008 Share Posted July 30, 2008 Goods have to be fit for purpose, the fact it almost burst into flames is a safety issue: I would be talking to Proel who I have always found to be very helpful. Quote Link to comment Share on other sites More sharing options...
Basszilla Posted July 30, 2008 Share Posted July 30, 2008 Yeah, you're right. I've just shot them an email about it so we'll see what comes back... Quote Link to comment Share on other sites More sharing options...
escholl Posted July 30, 2008 Share Posted July 30, 2008 [quote name='Basszilla' post='251208' date='Jul 30 2008, 12:11 PM']I managed to kill my MB amp last night. The sound went but the power light stayed on. 5 mins later it's almost bursting into flames. Smoke shooting out of the vents like nobodies business ha ha. Thing was, I never drive it to clipping point and I don't really push the power section 'that' hard either!!! Oh well, it was good while it lasted. It's only 3 years old though I wouldn've thought it'd last a lot longer than that. I'm wondering if there's any point at all in contacting Proel/MB about it. Edit: I took it apart to see what had happened and I'd done some serious damage to the PCB, talk about chargrilled!!! Loads of components had melted etc... I took a series of photos of the innards, so i'll email them to MB at some point and ask them about their supposed miniscule component failure rate.[/quote] yikes. that should never really happen in properly designed equipment. health-and-safety lawsuit much? Quote Link to comment Share on other sites More sharing options...
stingrayfan Posted July 30, 2008 Share Posted July 30, 2008 [quote name='Basszilla' post='251208' date='Jul 30 2008, 12:11 PM']I managed to kill my MB amp last night. The sound went but the power light stayed on. 5 mins later it's almost bursting into flames. Smoke shooting out of the vents like nobodies business ha ha.[/quote] I love a BBQ - could you chuck a burger on for me please? Quote Link to comment Share on other sites More sharing options...
aerkat Posted September 5, 2008 Share Posted September 5, 2008 [quote name='Basszilla' post='251208' date='Jul 30 2008, 12:11 PM']Edit: I took it apart to see what had happened and I'd done some serious damage to the PCB, talk about chargrilled!!! Loads of components had melted etc... I took a series of photos of the innards, so i'll email them to MB at some point and ask them about their supposed miniscule component failure rate.[/quote] Hi, I'd be interested to know what happened when you contacted Markbass? Do you have a theory as to what went wrong with your amp? I've just invested in an SD800, so I'd like to avoid spontaneous combustible events if at all possible! ...And did you replace like with like or buy something new? Thanks! kat Quote Link to comment Share on other sites More sharing options...
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