Mesa Nomad Pots have dead spots, what's up with that?

[SteveB]

Hi

Just got a beautiful Nomad 45 112 from a guy who bought it new and never took it out of his living room...and never played it judging from how clean it is...however, there are a few pots with "dead spots" in them, but there is nothing in the feel of the pot or travel that feels wrong but the sound, be it volume, tone or whatever it is controlling just hits a dead spot, then carries on with a modified, strange reading after that.

Unfortunately the output volume and solo volume pot are both affected by this disorder. I wondered for a while if cleaning them would help, but I found a thread somewhere saying that this is a known problem. Something about plastic shafts on the pots. Anyone had that issue and dealt with it using anything but pot replacement? Just wondering if putting some control cleaner in them would help...but afraid they are somehow broken inside. Funny since they are nearly new.

And of course, I will need to deal with the no-arrow or number control knobs...wonder what they were thinking with those...tney are totally useless. I read a post somewhere tonight where the guy said Mesa was giving him new pots AND new knobs F-Series style with the little white line for visibility. Must try that but nobody could be THAT generous, could they? I have about 5 bad pots.

Anyway, all that is secondary to how it sounds! My goodness, this thing is quite amazing. Almost comes close to my channel switching Twin for sweetness and versatility at half the size and 2/3 the weight.

Thanks for any and all advice available on those pots. The guy I got it from said he bought it new 4 years ago. I got the tags, manuals, all in the Mesa envelope from him with the amp. Pretty sweet even if I did pay too much for it...those tones ...omg.

[Garydean]

It sure wouldn't hurt to clean them real good with De-oxit first. I've found on a few occasions that the casing tabs will separate from the wafer. Simply bending them back in place will snug up the pot and make them work again.

Gary

[Mark Black]

First look carefully at the pots and see if the backs are loose - happens all the time when controls get bumped during transport. If the backs are loose the wiper won't make good contact. Could be as simple as pulling the pot out far enough to get to it and re-crimping the ears that hold the back on. Shouldn't even have to desolder them.

If the backs aren't loose call Mesa and tell them what you have going on - they may send you free replacements since this is a known issue. There may also be other pots of the same bad batch in there that are still working but should be replaced. The Mesa tech can probably talk you through what to look for to pick them out. Probably it will be as simple as finding all the ones with the same color phenolic as the bad ones and getting the part numbers off the backs.

Even if you have to pay for them replacement is pretty much the only option (if these are the bad ones) due to the way they go bad. Inside the pot there is a plastic disc which is rotated by the pot shaft. The wiper contacts are mounted by small plastic posts on the disc which are melted over to retain the contacts. The melted part of the posts break off and allow the wiper contact to flop around or simply have reduced pressure against the resistance track.

Every manufacturer falls victim to a bad batch of parts now and then.

I like the Nomads too - good sounding amps.

Good luck!

[Enzo]

And let me also say to look at your controls to see if the back cover seems to be loose on the funny ones. A bump on the knob pushes the back out. The back cover is what holds the wiper assembly in position over the resistance stripe.

[SteveB]

Talked to Mesa today on the bad pots

Talked to a Mesa Customer Service guy today who offered to sell me new pots for my 'New Old Stock' Nomad 45 for a buck fifty each. I told him the amp probably has more play time in the last day with me than the last 4 years with the PO, which makes me really feel MESA ought to go good for them at no charge to the new owner (me)...hmmm. Entitlement or what...

By the way this guy probably didn't get a clue of what he could get out of this amp til I bought it - he never read the manual and his other amp is a 2x12 Marshall combo which is probably as far from this Nomad as you can get.

Don't know if he ever got a decent tone out of the Nomad but he just about fell down when I put a Strat with Classic Stacks on it and wailed away for a few minutes tweaking tones (I have a Studio Caliber DC-2 so know how touchy Boogies are about settings) - maybe with the too-many-choices of tone thing and all, he got scared of the dead zones in the pots and panicked.

Anyway, I sure hopedBoogie will replace all the pots for me gratis and I can do my part and just solder them in...doesn't look that way yet but we'll see. It's almost a shame to even open up the amp, it has never had a screw turned on it.

And to boot, at a buck fifty each, how good can the pots be! Assuming that high end manufacturers like M-B would only use the best components could be a mistake, eh...

Apparently according to the Mesa chap, there was a 'bad batch' when they built some of the Nomads - and again, wouldn't that be their issue? I also mentioned to him the possibility of the pot backs getting bumped loose though considering the new condition the amp is in it's unlikely.

He said just replace them wholesale, so I will open the amp up anyway to check them out and hopefully they are just mechanically failed; however 2 of the 3 on the back controlling reverb-per-channel are also failed, and I don't understand how anyone could have bumped them inside that back area, so strongly suspect crapped out pots with the OEM fault (hmmm.....melted plastic, a great substitute for micarta and brass - NOT) as was so clearly described by other contributors...thanks for the clarity, bros.

Gonna keep chewing on this and will update on progress....

By the way they also sell those F series/Lonestar knobs for $1.35 each to fix the "can't see the flippin' pointer" situation with the stock knobs...think I'd rather have something more like the mini skirted knobs on the DC-2 if they fit the same shafts. Got to check that too...yikes. Too many amps, too little time....

Cheers and thanks,


Steve B

[Rick Erickson]

And to boot, at a buck fifty each, how good can the pots be!

Would you feel better if they charged you more? <LOL>
Seriously - I don't know of any major manufacturer that is using the "best" pots available. Do you think CTS pots were the best Leo Fender could have found?
Mesa had a problem with the construction of some pots they were using. I don't recall the exact nature of the defect, but the new pots fix this problem - they aren't the same construction - so at least they (Mesa) are addressing the issue and not just sending you more junk parts to install. $1.50 ea. is a bargain. Be glad they will even sell them to you. I deal regularly with manufacturers that force the general public (and independent service shops) to buy at Retail from their authorized service centers or parts distributors.

RE

[SteveB]

I know, just whining...

Hey Rick, of course you're right, even to do the whole amp (think it's 25 pots) is pretty cheap compared to retail prices. And none of the other Mesa gear I have owned was ever anything but good quality....BTW this Nomad sure sounds nice and is worth it...I smile every time I hear that clean channel...much better and more versatile than my DC-2 Studio cal.

Cheers

(Hangin my Head in Vancouver)