Horrendous feedback type sound N112

[LaVern Skarzenski]

Hello All,
I have a Peavey Nashville 112 purchased new in 2003, label on front says Made in USA. It is setup in my music room and doesn't get moved or tore down anymore. I am having a problem that started about 6 months ago with a terribly loud, ear piercing feedback type noise when ever the Mids are turned on. As long as I turn them off (Counter clockwise) all the way it doesn't occur. It started out as only occasionally, but now it's to the point where I cannot have them on at all. I have tried various settings on every knob on the front panel and nothing changes. I have tried both the single cord volume and the double chord. I have tried guitar to volume pedal, pedal to amp. Everything I have read in the past about spraying the pots and cleaning the jacks with electronic cleaner. I have sprayed pot shafts from the outside with 'CRC QD Electronic Cleaner', rotating them, and did the same with the jacks by spraying and then inserting and removing a cable end but to no avail. Perhaps this is not the correct way to do it, so can somebody tell me what else I may do to alleviate this problem, short of shipping it to a repair shop, or is that the only thing that will work? Perhaps there is a better way to clean them. Thanks.

[Jim Palenscar]

Change the mid pot

[LaVern Skarzenski]

Thanks for the reply. Is that something that requires any high skill electronics? I take it one must pull the top end out and some soldering would be required? I've made several lap steels and did the soldering required for them.
LaVern

[Gil James]

Pretty common occurrence on these amps. The first time it did it to me, I about had a heart attack! I think my left ear was permanently damaged! My solution was to turn the gain and master all the way down, then rotate the mid knobs ferociously, ending them up in the correct positions, then slowly increase the gain. After about 2 or 3 tries it stopped. Then I put a piece of tape over those knobs. Lol. All I ever use it for is on one steel, so I've never had to change em. And didn't want anybody else fooling with them. It's never done it again. If you use it for other instruments,I'd take Jim's advice.

[LaVern Skarzenski]

I just took a look at it and first off I cannot make out how to disconnect the reverb tank. The connections don't look like any of the "molex" connections I've seen online. I did see a video on cleaning the pots where he removed the "head" on a Bandit 112, and it looks like the pot removal and replacement might be out of my league. I have a 112 Bandit and that doesn't sound too bad, perhaps that will be my amp for a while. Would like to find a Peavey dealer nearby that's certified for repairs. Thanks for the replies.

[Stephen Cowell]

You can change the Mid pot (it's a specific dual pot) or you can yank the Mid chip to stop the squeal. Same thing happened to my N1000.

[Ken Fox]

Unless you have very good skills with desoldering you may easily destroy the traces on the board. There are 7 connections to be desoldered. 4 are the mounting bracket and 3 easy to burn up electrical connections for the pot itself
I would send it to Peavey or a local electronics repair shop

[LaVern Skarzenski]

Unless you have very good skills with desoldering you may easily destroy the traces on the board. There are 7 connections to be desoldered. 4 are the mounting bracket and 3 easy to burn up electrical connections for the pot itself
I would send it to Peavey or a local electronics repair shop

Thanks Ken, I see there is a certified Peavey repair center in Erie , 45minutes away. I will definitely not attempt this myself.

LaVern

[Lee Baucum]

I just had a flashback to many, many years ago when some of us had our ears blasted by our Nashville 400 amps.

I believe it was the Mid-Shift pot. One little turn and it sounded like a bomb going off.



I wonder how many of those tanks are still in operation out there. Practically indestructible.

~Lee

[Richard Sinkler]

I just had a flashback to many, many years ago when some of us had our ears blasted by our Nashville 400 amps.

I believe it was the Mid-Shift pot. One little turn and it sounded like a bomb going off.



I wonder how many of those tanks are still in operation out there. Practically indestructible.

~Lee

Yup. My NV400 mid shift pops so loud that the city starts blasting the air raid sirens.

[Dennis Saydak]

What a coincidence to come across this thread just when I'm dealing with a really bad crackling mid pot issue. I'm absolutely amazed to have this problem since I'm essentially a “set it and leave it” kind of guy. My amp has only been moved once since I bought it new back in 2007; that was to install the chip mod package that I got from Mr. Fox. That was a relatively simple task as the parts were easy to access. However, that is not the case with pot replacement. Given how common this problem seems to be, I have to wonder exactly why?

To gain access to the solder side of the circuit board, there are 8 pots and 6 jacks that require removing their knobs and retaining nuts, plus three small screws. That's means a lot of careful work to not break anything or bend a shaft. My mid pot knob didn't want to come off easily. I had to pry it off and I made a notched tool from hard maple for that purpose which, worked like a charm.

To answer the above question about disconnecting the revb connector ....... That wasn't necessary for me. Instead, I gently bent up the cable wires (see attached picture) at the connector block, which allowed me to slip it through the hole in the chassis, wires intact. I also removed the two cable clamp screws on the side of the cabinet holding the revb cable for some extra work space slack.

Anyway, here's a couple of pictures of the “innards” for anyone thinking about doing this kind of service work themselves. BTW, I do have the necessary experience and tools to tackle the job myself. Obviously, proceed at your own risk and with appropriate caution.

Revb Connector.JPG

NV112.JPG

[Dave Magram]

LaVern,

Before you replace the mid potentiometer, which seems to me a big job with a high risk of damaging the circuit board,, you might try just squirting some DeOxit Electronics Cleaner/Lubricant inside it.

I believe that the mid pot is the only one without an access hole(!), so what I did when I had a similar problem several years ago, was lay the amp on its back on the floor, remove the mid-pot knob, and squirt the DeOxit down the shaft while rotating it. I gave it a good soaking, and shazam! the noise stopped and never came back.

BTW, use DeOxit--do not use a simple electronics cleaner without lubricant.

_ Dave

[LaVern Skarzenski]

Thank you everybody for your advice. I do have a Certified Peavey Service repairman just about 45 minutes from my home. I can assure you all that I won't be attempting any kind of dismantling myself, not when there is someone so close that I can drive and avoid the hassle of shipping it. Thanks again.
LaVern