LMII cuts out

Silas Stingy · #1 08-01-2011, 08:23 AM

Hi chaps, I wonder if any of you can help. My Markbass LMII is occasionally shutting down, the power light remains on but there is no output from the speaker or DI. The clip light is never on when I play, the fan is operating correctly, the amp is clean and tidy inside and I'm running a 8ohm Ashdown cab.
I've checked out other threads on this and they have mentioned the speakon output is a little dodgy on the amp and it would appear that the same can be said of my amp. From now on I will connect via the 1/4" and see how it goes. I was just wondering if anyone else had experienced the DI shutting down as well as the amp section due to the faulty speakon? I guess what I'm asking is does the DI shut off if the amp goes into protect mode? I'm hoping this isn't something more sinister!

BassmanPaul · #2 08-01-2011, 10:47 AM

The fact that the amp has a speakon has no bearing on the DI. If the amp shuts down and at the same time the DI does too your amp has a problem and needs to go to a tech.

RickenBoogie · #3 08-01-2011, 11:05 AM

+1 to BPauls's advice, a good amp tech can sort you right out. You might try cleaning the effects loop jacks with some De-Oxit first.

Silas Stingy · #4 08-01-2011, 12:13 PM

Thanks guys. I think I'll take your advice and get the thing checked out. Nothing worse than an amp that's waiting to surprise you. Typically I sold the Ashdown last month so no backup, you live and learn

**JxBass** · #5 08-01-2011, 02:20 PM

Quote:

Originally Posted by Silas Stingy

Thanks guys. I think I'll take your advice and get the thing checked out. Nothing worse than an amp that's waiting to surprise you.

Kudos to presenting well the symptoms, setup, and tests before posting. It got you worthwhile, succinct advice.

ErnieD · #6 08-01-2011, 04:22 PM

do try the 1/4" jacks into the effects send/return on the LMII, with or without De-Oxit. I've done this and suggested this to a few TBers and they were amazed the problem went away.

Now, I've only done this to a GK-1001 back in the day but others have tried it on their different brand amps and its' worked. Only takes a few seconds and just might fix it cost free. I've since bought a can of DeOxit and use it on amps, basses as needed, works great.

I too experienced the dodgy speakon jacks using off-brand speakon cables on my finicky LMII. A 1/4" or true Speakon connnector works best. Let us know what you find.

rodl2005 · #7 08-01-2011, 09:54 PM

There was posts re this- the LMII cutting out in the LMII mega-thread.
Mine did it ONCE. After that,I did what ppl suggested in the thread, & that was Only use a 1/4" plug style speaker lead outta the LMII dual purpose speakon-speaker out.
So, I only used 'old fashioned' 1/4" speaker leads out of my LMII & I've never had a problem since-3yrs or more, gigging it once/week.

will33 · #8 08-01-2011, 10:05 PM

Sounds like the speakon may be prone to short or at least bleed some.....not that I'm an electrical guru or tech or anything but the problem is obviously at the output connection or the board/traces it's connected to if the 1/4 doesn't show these problems.

rodl2005 · #9 08-01-2011, 10:15 PM

Yep, something like that. I'm NO tech, by a long shot. But my LMII hasn't shown ANY flaws at all & has not ever cut out again since that one time.

Thurisarz · #10 08-02-2011, 03:57 AM

I have the same problem, but reversed, my 1/4" is dead. My LM250 has the same symptoms as the OP wrote about.

The problem is i have no Speakon cable to try it out with. I will buy one and come back to you with an update!

rodl2005 · #11 08-02-2011, 04:50 AM

Yeah please do! I'd be interested to hear the outcome of this.
As I said, I've had no probs since, & this was probly 3 yrs ago.
Come to think of it, I have used speakon speaker leads a few times since-with no probs. But I try to remember to have a 1/4" lead for use with the LMII.
KEEP us informed.

Russell L · #12 08-02-2011, 06:31 AM

Been gigging my LMII with 1/4" for three years with no probs so far. I was thinking about getting a SpeakOn, but now I wonder.

Silas Stingy · #13 08-03-2011, 10:12 AM

Just a bit of an update on this. I emailed MB with the symptoms, DI cutting out etc and had a prompt response telling me to first try a new speaker lead. The only other I have is the 1/4" ,thought I'd give it a try in rehearsal. I've also cleaned the FX in/outs2 as RB suggested, after 2 hours of playing the amp was operating as normal. Let's see what happens at a gig (other than me getting my arse kicked if the amp dies again

)

Thurisarz · #14 08-09-2011, 11:01 AM

Ok heres an update, i bought a good quality speakon cable but the problem remains! Tried to use the effects loop, doesn't work!

I'm tempted to get the amp just cleaned up with DeoxIT, but since i'm a n00b with all things electronic i'm afraid i will damage the amp.

How should i use it or should i take it to a tech for clean up?