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PostPosted: Mon Apr 02, 2012 7:21 pm 
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Bottle Rocket

Joined: Tue Mar 27, 2012 9:38 pm
Posts: 7
I did every mod on this page to my Nomad 100 and let me tell you, wow what a difference. Thanks guys again for the shared info. I'll try to post the pics I took soon.


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PostPosted: Fri May 04, 2012 5:39 pm 
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Bottle Rocket

Joined: Tue Mar 27, 2012 9:38 pm
Posts: 7
Here's some pics after the mods. Thanks guys
Image
Image
Image
Image
Image


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PostPosted: Fri May 11, 2012 11:11 pm 
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Bottle Rocket

Joined: Sat Apr 24, 2010 1:23 am
Posts: 4
I did the FX Loop Mod to 47pf, and the mud mod, and it just woke the amp up, sounds much better.

Very easy to do with good results.

Last mod forme is swapping out the black shadow and putting in a vintage 30.

This amp sounds killer thru my 4x12 with vintage 30s.


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PostPosted: Sat May 12, 2012 5:15 pm 
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Bottle Rocket

Joined: Sat May 12, 2012 5:07 pm
Posts: 3
Hey just lookin for some help here... I performed all the mods on this page and now my Nomad 100 dies after it heats up. I reversed the 47pf mod and thought it was fixed, but soon as it heats up it shuts down to like 1% across all channels, and when I flip the standby on & off it comes right back for a few seconds and then dies again til I flip it. Endless cycle of frustration. Just wondering if anyone else has had this problem?

Thanks in advance, Frank


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PostPosted: Sun May 13, 2012 2:16 pm 
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Mark I

Joined: Thu Mar 26, 2009 7:20 am
Posts: 46
Frank,

Did your amp ever behave this way before modifying? When did you last change tubes? Did you perform any bias modifications? Did your amp work fine for awhile after modification and later start acting up, or did it go wacky right away? My first instinct says phase inverter or fx loop preamp tubes, but that`s a guess at best without actually seeing and hearing the amp.

You might try slaving the Nomad into another amp via FX loop send to see if the amp behaves normally on the preamp section. Or try patching in a signal to the FX return, to test the power amp section. Hopefully you can identify the location of the problem this way, and figure out if it`s something you did wrong or just a bad tube or other component coincidence.

Good luck, and happy hunting.

Pat the Cat

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USA Strat, Les Paul Studio, My 2204 clone, Weber 30w Alnico 12".


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PostPosted: Mon May 14, 2012 11:56 pm 
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Mark IV
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Joined: Tue May 29, 2007 12:58 pm
Posts: 740
Location: Indiana
i sold my nomad channel switching problems, i'm very happy to see my push to self mod had kept going strong. I do miss my mesa, it's tone and have grown tired of both the weight and sound of my MTS head.

_________________
Randall RM100 & Mesa Mark V
2x12 Recto & 1x12 Widebody ported.
Epiphone Z.W. bullseye Les Paul,
Epiphone limited edition Midnight Les Paul
Line 6 M13


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PostPosted: Tue May 15, 2012 1:00 am 
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Bottle Rocket

Joined: Sat May 12, 2012 5:07 pm
Posts: 3
Thanks Pat,

- Never had a problem before the Mods and the amp got wacky immediately after the mods. My biggest fault is that I did all the mods at once without checking the amp after each mod :/

- The tubes were allegedly replaced right before I bought it and the Mesa store here in Hollywood was familiar with the seller and the amp.

- I did no bias mods but I did do :

The "remove 2 caps mod"
The Reverb Mod
The NFB Mod
The parallel to series fx loop mod
The 47pf cap mod which I reversed

Since reversing the 47pf cap to stick the amp now fires up, sounds great, heats up and dies. Then I flip the standby and it comes back for a few seconds. The sound starts crackling and sputtering and the power light flickers to the crackle and sputter of the signal.

When you say to slave the amp into another, can I do that with an orange tiny terror that doesn't have an fx loop?

While its working it sounds awesome so I have to be close...


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PostPosted: Tue May 15, 2012 6:49 am 
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Mark II
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Joined: Thu Jun 09, 2011 1:05 pm
Posts: 57
When you say you reversed the 47pf cap, did you use a polarized cap in that position?

Beyond that, did you use caps that were rated with a high enough voltage? Because it's something that comes and goes and is affected by the standby switch, I'm wondering if it's a bad cap somewhere.


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PostPosted: Thu May 17, 2012 5:26 am 
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Mark I

Joined: Thu Mar 26, 2009 7:20 am
Posts: 46
What I meant by "slave" a different amp into your nomad means basically a line level signal going into your effects return jack. If you don't have anything to try this with, no big deal. I thought it might help to identify the part of the amp that is misbehaving. If you have some spare tubes, I'd try swapping out the tubes one at a time (pairs for the power tubes). It doesn't hurt to try, and it won't cost you anything.

_________________
USA Strat, Les Paul Studio, My 2204 clone, Weber 30w Alnico 12".


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PostPosted: Sat May 19, 2012 11:14 pm 
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Mark III

Joined: Sat Nov 29, 2008 12:52 am
Posts: 340
If you clipped the caps in the power output section, which are sometimes used to prevent ultra high freq oscillations, maybe yours fell victim to oscillation and this is why its acting up. I don't know this for sure, because I've never had the problem, but seems to me this cap clipping thing brings this sort of behaviour on.


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PostPosted: Sat May 19, 2012 11:16 pm 
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Mark III

Joined: Sat Nov 29, 2008 12:52 am
Posts: 340
double post.


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PostPosted: Sun May 20, 2012 11:30 am 
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Donating Member

Joined: Sat Oct 01, 2005 2:27 pm
Posts: 5461
Location: Maui Wowee!
This is really cool! You guys have me totally gassing for a Nomad 55 combo now!
I just sold my Maverick and was looking for a replacement with much more gain.
You just might have saved me from buying a Mark V! :lol:

Frank,
With the Loop mod, the Send jack now has all of the signal passing through it.
Try using a short patch cable from the Send to the Return jack.
If this fixes your problem, put the 47pf cap back in and replace at least the Send jack, preferably both.

Also, double check your solder connections between wires 1 & 2. A bad connection here would definitely cause you to loose signal.
I would be willing to bet that it's the Send jack though.

Replace the jack with a high quality Switchcraft.
Send: http://www.tubesandmore.com/scripts/fox ... m=W-SC-12A
Return: http://www.tubesandmore.com/scripts/fox ... em=W-SC-11

_________________
Elvis said.......
Quote:
Amp techs do get shocked. :shock:


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PostPosted: Sun May 20, 2012 1:23 pm 
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Donating Member

Joined: Sat Oct 01, 2005 2:27 pm
Posts: 5461
Location: Maui Wowee!
Crap!
I was just looking at pictures of the Nomad guts.
If the patch cable works, you might have to order a jack from Mesa to replace the Send jack.
The Switchcraft jack would be really hard to install since these jacks are board mounted.

Another great alternative would be to install a switch that bypasses the switching mechanism in the Send jack.
This switch could easily be installed where the Mix pot was.

I am pretty sure (don't have one in front of me) that this is what the switch would look like (using a simple 2 position SPST switch)

Pin 1 - wire 1
Pin 2 - wire 2
Pin 3 - wire 3

Basically inserting a switch where the pot used to be and wiring it exactly the same way.
One position of the switch would tie the wire (wire 3) leaving the Send jack, before the switching mechanism to the wire (wire 2) that goes to the recovery stage of the Loop.
The other position would make the Loop work exactly as if you had not connected wire 3.

This would be a great way to not have to replace the jack.
If I got this wrong, someone please let me know.

_________________
Elvis said.......
Quote:
Amp techs do get shocked. :shock:


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PostPosted: Mon May 21, 2012 6:57 am 
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Mark II
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Joined: Thu Jun 09, 2011 1:05 pm
Posts: 57
Having done the parallel to series mod on my Nomad 100, I can confirm that you need to run a patch cable from send to return if you are not running effects in your loop. I installed a Push/Pull pot so I can do Series or Parallel so I don't need a patch cable when I'm not running my normal effects loop stuff.


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PostPosted: Mon May 21, 2012 11:44 am 
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Bottle Rocket

Joined: Sat May 12, 2012 5:07 pm
Posts: 3
That's it! The patch cable works!!

I was starting to think it was a tube but this is obviously the culprit.

Thanks guys!!!!

Frank


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