Markbass LMII power problem!

[craigrock]

Hi all, brand new user here, though I've searched these forums as a lurker a few times over the past year as I have gone on a gear hunt.

I'm a fairly new bassist: made the switch from years of guitar just over a year ago to join the band I am currently playing in. I didn't have a bass or amp at the time. I bought a decently loud practice amp with a 15" speaker at first but quickly needed to upgrade as we had begun getting some decent gigs.

I found the following rig on craigslist, and after reading up on the gear decided to buy it second-hand:

LM II head > Bag End D10BX-D cab (the 18" deep 2x10)

It has been a great rig; that is, until the LM II recently shorted out while I was playing. After trying to unplug and turn it back on a few times, I took it to a local amp genius who determined that the fuse right under the IEC power input is blowing as soon as it is turned on. Replacing the fuse did not work, as the new fuse would blow as soon as the power switch was turned on. He tried to get some support from Markbass but all they would say is that he needed to have me bring it to an authorized dealer. Since he is unfamiliar with Markbass he didn't want to start trying anything crazy, so as of right now I am pretty stuck with trying to find a solution.

Since I bought this used it is obviously not under warranty. I have emailed Markbass service twice and have not received a response. The only "authorized distributor" listed on the Markbass site is GC, and they do not fix amps.

I LOVE the sound I can get through the LM II and really want to get this fixed. I don't think I would buy one new due to the lack of service from Markbass on this (I have heard great things about Genz-Benz and am shopping for a good lightweight G-B head...thinking of the 6.0 now).

Does anybody have any potential troubleshooting ideas on this? Any help would be greatly appreciated...I miss my LM-II tone!!!

Thanks!!

-Craig

[GrowlerBox]

Try a PM to Peter Murray (find him in the members list) -- he's the Markbass rep on TalkBass.

[craigrock]

Thank you very much!!

[rodl2005]

Keep us posted as to your outcome please

[figuredbass]

The instantly blowing fuse may be a sign that a power transistor has blown out. However, you really have no choice but to have Markbass repair it as the LMII circuit schematic is not publicly available.

[craigrock]

figured...yes, that's exactly what my local amp guy said. He said at least one transistor is blown, but he couldn't get any schematic from Markbass and so couldn't fix it. I PM'd Peter, waiting on a response. Luckily I have access to a sweet Genz-Benz head for my gigs tonight and tomorrow; after that we don't have anything booked until after we finish our EP so I have a little time to get my LM-II back up and running. It's such a great little amp, and perfect for the tone I am going for within our band.

I will definitely keep you all posted. And thanks again Growler...

[BassmanPaul]

PM me with a proper email address and I'll send you a little something.

[felixthecat64]

I was playing a gig last night and my Markbass just cut out. The power light remained on, but the speaker our and the DI went dead. I power cycled the amp and it came back to life. This happened three times over the course of the night. Has anyone else had this problem?

[BassmanPaul]

What speaker cabinets were you using and what are the impedances???