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PostPosted: Sun Feb 19, 2017 3:41 pm 
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Bottle Rocket

Joined: Tue Mar 01, 2011 3:47 pm
Posts: 11
Hi guys

I just bought a mark ii c+ and love it. It was shipped to me ground, and took a week to arrive, so I assume I was riding on a truck for a week. It worked well for about 2 days. Then the crackles started. At first it would crackle at startup for about 10 minutes, then after about 3 hours. Then it would only crackle at startup and after an hour. Eventually it crackled every time it was powered on. I bought new tubes and installed them. No differemce. I should also mention I swapped the speaker.

So I took it to my usual repair guy, and here's what he did - 1. Gave it a good once over, including fixing a loose/falling apart solder joint in the V1 socket. 2. Swapped V1. It didn't crackle at his shop. Of course I got it home, crackled immediately the next morning. Called him back then took it back. He then 1. Swapped both power tube sockets. 2. Re-tensioned the preamp tube sockets. 3. Gave all the tube sockets a good cleaning. 4. Replaced one cap. Not sure which one.

He had it on at his shop for two hours with volume at max through his own speaker cab - not a single crackle. I thought it was fixed - after an hour of use began to crackle.... took it to a local big repair shop. The guy there didn't seem like he knew what it was either....

So I'm looking for either a diagnosis I could call this guy with to help him, or a good boogie repair shop in Chicagoland. Help!!!!


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PostPosted: Sun Feb 19, 2017 6:06 pm 
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Donating Member

Joined: Tue May 05, 2015 9:07 am
Posts: 76
Location: Chicago
When the c+ I bought last summer got damaged during shipping I took it to Chicago Amp Works.

_________________
Mark IIc+ HR combo x 2
Mark IIc+ HR wide head
Mark IIc+ DR combo
Mark IIc>c+ HR head
Mark IIc>c+ DRG combo
Mark V 25
Mini Rec


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PostPosted: Mon Feb 20, 2017 12:16 am 
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Mark II

Joined: Tue Nov 29, 2011 2:52 am
Posts: 56
I had similar problems with crackling, If you look at the thread of mine "Mark III died again" you go to the last page and check out what was wrong with mine, sounds very similar - it ended up being a blob of Solder under the V2 pre amp valve socket - had to pull the board to see it, but that in fact was the cause of the crackle. Mine would do it on start up - and sometimes when loud palm muting heavy riffage playing at volume - anyway - I don't know if that will be your problem, but It was mine, worth a look anyway

Casey


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PostPosted: Mon Feb 20, 2017 10:52 am 
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Bottle Rocket

Joined: Tue Mar 01, 2011 3:47 pm
Posts: 11
HI kc - I looked on here (seems to be lots of these problems with the older mark series?) but didn't see your thread. And you're right, this sounds like the same type of problem. I will definitely tell my tech about it. I have compiled a list of possible culprits - the tech is gonna hate me!

and xdg - the 100 watt with reverb no graphic EQ iic+ is the one I was looking for! if you ever want to sell one locally in Chicago without having to ship (damage!) it, please please please write me a private message. I looked for one online for months and got sick of looking and got this 60 watter. It's not enough power (yes i know its a lot) but I need LOUD clean clean. Really, please write me.

Thanks for the help so far guys - any more help would be greatly appreciated!


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PostPosted: Mon Feb 20, 2017 3:31 pm 
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Donating Member

Joined: Tue May 05, 2015 9:07 am
Posts: 76
Location: Chicago
I won't be selling any of my c+'s anytime soon. It took years to find another HR combo. I'm actually looking for another HR to add to my collection. The guy I bought my DR combo from last fall still has 5 c+'s. And I thought I had a problem! :)

_________________
Mark IIc+ HR combo x 2
Mark IIc+ HR wide head
Mark IIc+ DR combo
Mark IIc>c+ HR head
Mark IIc>c+ DRG combo
Mark V 25
Mini Rec


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PostPosted: Mon Feb 20, 2017 3:58 pm 
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Bottle Rocket

Joined: Tue Mar 01, 2011 3:47 pm
Posts: 11
xdg999 :D 8)

Enjoy!!


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PostPosted: Mon Feb 20, 2017 7:48 pm 
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Mark II

Joined: Tue Nov 29, 2011 2:52 am
Posts: 56
http://forum.grailtone.com/viewtopic.php?f=27&t=71553

try that one

casey


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PostPosted: Wed Feb 22, 2017 5:43 am 
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Donating Member

Joined: Thu Jul 09, 2009 1:41 am
Posts: 375
Location: Canberra, Australia
That sounds def intermittent and equally poss electronic OR mechanical in aetiology..

U/someone NEEDS to narrow down the error area ie: V1, V2, V3 etc etc etc etc.. and which channel.. or both...
Some random thoughts without chassis on my bench...:
Assuming all voltages are in spec and STABLE, without ripple, at least verify a preamp or poweramp source. This is imperative to not waste a lot of time and/or money. Or both.
If power, clean the hell outta board and sockets. Check leaky coupling caps. Check screen grids not breaking down (not uncommon with heat and age or a dying 6L6 frying them..)
If pre, check failing carbon comps, (CRO +/- chopstick/tapping), crud ANYWHERE from input jack forward. Check all earths ESP jacks. Again, leaky coupling caps - spurrious DC can crackle but constant gives humm..
Check DC BETWEEN tracks.. - one of my Mk II's and my Kitty Hawk M1. Complete bastard to find..
?Failing LDR's? CRO will show quickly and easily..

Re KC's solder blob - the IIc sockets come UP through the board. No blobs. AND board is 99% single side

And usual checks - fx jacks, crud in pots, DC on pots, dry joints esp in high heat areas, rev jacks, eq sliders..
The list is long hence narrow the area ASAP..
There's some ideas to drive yr techs a bit crazy.. They'll have their own methods but I've seen all of the above..
As always, pls post results for future readers..

Cheers, Dave

_________________
Mk I,export,GEQ,cream
Mk IIA,export,rev,cream
Mk IIB,export,rev, tweed tolex !!
Mk IIB,export, rev,GEQ,simul, black
Mk III head,rev,GEQ,cream
Kitty Hawk M1 head
Fender 75, export, 1973,15".
Fender 6G6A Bandmaster 1962
Fender AA763 Bandmaster 1964


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PostPosted: Wed Feb 22, 2017 5:29 pm 
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Bottle Rocket

Joined: Tue Mar 01, 2011 3:47 pm
Posts: 11
Will do, thanks Dave!


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PostPosted: Fri Feb 24, 2017 12:51 pm 
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Dual Recto

Joined: Tue Feb 07, 2006 11:21 pm
Posts: 2823
Location: North Alabama C+ Mafia-Kingpin
A slightly broken ground strip fom one of the pots will drive you crazy also. 8)

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"One of these days, I'm gonna change my evil ways....... one of these days.


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PostPosted: Fri Mar 03, 2017 6:03 pm 
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Bottle Rocket

Joined: Tue Mar 01, 2011 3:47 pm
Posts: 11
hi guys -

its back and its working! i'm excited. its sounding great.

he told me there were a bunch of solder joints that were suspect (didn't tell me where and i was so excited to get it back I didn't ask...) and changed some plates having to do with v1 and v2. Again, kinda excited and don't know much about plates.

If anyone needs this info i can call back and ask - just PM me.

Again, thanks for the help guys!


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PostPosted: Fri Mar 03, 2017 6:14 pm 
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Donating Member

Joined: Tue May 05, 2015 9:07 am
Posts: 76
Location: Chicago
That's good to hear. Enjoy!

_________________
Mark IIc+ HR combo x 2
Mark IIc+ HR wide head
Mark IIc+ DR combo
Mark IIc>c+ HR head
Mark IIc>c+ DRG combo
Mark V 25
Mini Rec


Top
 Profile  
 
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