Mark III died again - UPDATE 25/1/17 -

So my Mark III blue stripe died again over the weekend, reliability has been pretty bad with my amp this is now the 3rd time its broken down, this time similar as the last, had some major crackles and static noise then nothing, and the smell of burnt electrical's - but all tubes seem to be glowing.

I really like the sound of the amp, when its going it sounds unreal but I think I might piss it off and get a fender or Ceriatone JM - SSS or something along them lines. Anyone else have reliability issues with theirs ??

Casey

Other than a bad valve a couple of times, my purple stripe has been super reliable for nearly 30 years over hundreds of gigs and near daily studio use. I am considering a cap job but only because of its age rather than noise problems. The valve problem was also only when I used power valves that were not Mesa tested but claimed by sellers to be compatible.

Has it any mods by previous owners, has it been properly cleaned, checked and overhauled by an amp tech? New set of correct value tubes?

Yea mate - its been modified to use EL34 valves - yes its been to a recommended repairer here in Brisbane by the name of BJ Amps - he is recommended by Pro Audio (the importer) - he has serviced - cleaned - replaced screen grid resistors, valves - some resistor on the board that fried last time (you can view that in one of my posts if you look at an earlier post) and a few other things I just cant remember right now.

I did contact Mesa Boogie about the problems it has - they sent Pro Audio a message to contact me (Which they did) but the only thing that they would do was to completely overhaul the amp components and bring it back to the way it left the factory - the thing is I like the way it sounds now and I don't want to change that - I just want the crackle & pop to stop on start up - its always made this noise - so until that issue is fixed I don't think it will ever be OK or reliable, end of the day I may as well put the money towards a Mark V or a Jp2c >?

casey

Shame. Maybe just got a bad one. Bad luck. I love my Mark 3 but if I ever had to replace it I'd be looking at Boogie again... Mark IV or V, RoadKing or a Lonestar

Do you play through the amp regularly, or just every now and then?

A similar thing happened to me a long time ago.
I used to only play my .50 Caliber a few times a month, and I'd crank it up when I did. It would crackle and hiss, and after a bout 20 minutes, the volume would drop (to almost nothing), and it would sound fuzzy, even on the clean channel.

A tech told me to spray it down with TV tuner spray. It made the amp sound like new again.

He said my playing habits were at fault. Crud was building up around the contacts, and if I played more often, it would burn it off, or some such voodoo.

Try De-oxit, and remove the tubes and spray down in the contacts. It's worth a shot before you take it to a tech again.

Good luck!

Hi Mate

Yea I play it fairly regular, 2-3 times a week, sometimes more (depends on the Mrs - lol) - but it crackles and hisses and mucks around every time I turn it on, just this time it went bang and fried.

I also have a dual recto - but I just cant get that to sound as good for what I play, its a different animal to the Mark III, I think I like the Mark series a lot more, but on the other hand the Mark series cant sound like a recto - so yea I keep it around, but thinking of moving it on aswell.

I'm now contemplating getting a SSS from Ceriatone, its Dumble clone of the Steel String Slinger or a Two Rock, very John Mayerish which is what I have been noodling around with these days - you know that live concert - Where the light is - that Strat and amp combination just sound to my ears a very nice mix, I just wished I had Johns chops and musical arrangement.

Casey

Casey,

immediately I'm thinking same thing as tommyhawke13.
Crud on the board, causing micro-shorts between tracks - usually HV and signal tracks.
Plenty other possibles, but that's my initial expect..

Has it been tried since the big crackle and smell issue ??

If U wanna pull the chassis and bubble/box it to Canberra I'm happy to look at it for U..

PM and we can sort it..

Dave

Yes, Casey.

I am akeen to think like Dave (McBarry) and tommyhawke13 too : a complete cleaning of the amp circuit would be a good thing to do, if you can perform it (it's a long, delicate and accurate job, something like a paleontologist work, nothing to do with just spraying a product here and there or worse: everywhere :x ...). Moreover, doing that, it would help you to detect an hidden / unsuspected default.

A+!

Had a little play around with diagnostics tonight - I pulled the power tubes out and put them in my dual rectifier and the power valves are fine - I searched for loose connections, couldn't find anything- I searched for scorching or burnt things - couldn't find anything- I done a tube roll - still found nothing - I plugged my guitar into the fx return and I had a nice tone but all the front dials don't do anything as they are on the pre amp before the fx circuit - so something to do with the input pre amp side of things -

There is some noise of my playing through the input but it is very low output - but there is white noise that is constant- it still crackles a little when the standby switch is turned on, we checked filter caps but only with a multi meter so not accurate but they seem to build capacity- I don't have any other way to check it - does any of this sound like they know what might be causing the problem??
Casey

I know several cases, where effects loop causes that kinda behavior.

Disconnect everything but your speaker cable. Plug your (100% fit) guitar cable in input. Test. Switch all channels by using push pull pots. Make sure it is not about channels.

"Wake up" loop jacks by using a plug in a manner that would make you look very odd if someone looked (put in, pull out gently but firmly several times as long you can be sure that possible dirt on contacts has gone). If no help, try to use short cable in loop just to test/make sure the problem is/is not in your loop.

I will try the short cable in the loop, but I think it has something to do with the signal path in the preamp as the amp is doing everything that its suppose to do, its switching, loop works, I can hear the gain volume working, I can hear all the push pull pots working etc, the only thing is its not amplifying the sound to the power side of the amp, but all the functions are working, it beats me

casey

Hi Casey, did U get the MkIII sorted ?
Hope so...

G'day Dave


Mate - I haven't - the old man looked at it but he couldn't find anything visually wrong - so I wanted someone in the know to do it. I spoke to the Tech at Pro Audio who was pretty helpful, but he reckons if he does anything he will replace everything 1st (overhaul it). So that's as far as its gone.

Failing all that I was just going to take it back to B J Amps as he is local for me and pretty easy to deal with.

But now I'm thinking of buying a Mark IV instead

Are you interested in the mark III still as it is ???

Casey

I should have said, I have just been using it as a power amp through the effects loop, everything is working in that respect, the EQ works and master volume - but no reverb or presence control. or any of the front knobs.

When I do plug into the front of the amp input - I can hear what im playing etc. But its not amplified - its not very loud - so it has to be the input circuit to the power amp.

casey

When I powered it up after dad done some testing and, I could smell something hot - I seen a little smoke for a short time - but no smoke since then.

I checked all tubes out of the Mark III in my dual rectifier, and all sounded fine - I also done a tube roll as well with no change - so I don't think its tube related, and I don't reckon it would cost much to fix as there really is nothing visually wrong, so maybe dirt - cracked track or trace wire, failing components in the input circuit - yea. but anyway - its tech time either way

casey

Hi Casey, that sucks that it's still not behaving..

Yeah, John at Pro Audio is a really nice guys and knows Boogies v well.. Getting it back to factory would certainly locate the fault.. but at wot cost...!!

I'm not suprised its not showing itself visually as yet - and even if the source of the heated part or a bit of smoke leakage is found, there's no guarantee how far else through the circuit the root cause is..

But I'm a sucker for fixer-upper amps.. problem is I rarely sell them...

A Blue stripe Mk 3 would be kinda cool to keep company with my others though..!!

Is it head or combo and what kinds $'s would U be thinking ?

PM or email if U like so we don't hijack the thread - although I'll certainly post what I find if it make it's way to frigging cold Canberra..!!

Dave

!!UPDATE !!

So I took my boogie back to B J amps here in Brisbane Australia - as was thought he had to pull the board to diagnose the problem - but he found the problem

A big blob of solder had formed either from factory (which he thinks where it was) or a previous repair, this blob was so close to the pins that depending on heat , vibrations, moisture levels etc could actually short on the inside of the preamp valve base. The pre amp valve base is so tiny but this small blob none the less is the culprit



He also shorted one valve in the process so I replaced a set - also in the lead circuit there was a little black component - which I cant remember the name of is - and now all fixed, no crackling - no bad vibes, just awesome awesome tone!!

Casey