On-Off switch problem with Nashville 400 amps

John Clarke · Post by **John Clarke** » 11 Apr 2015 8:52 am

I have a problem with Peavey Nashville 400's that keep popping on and off when the switch is turned on. Sometimes the amp will not turn on at all. I have had 3 of them and they all do it. They are from the 80's and 90's, so maybe it is an age issue.

John Clarke · Post by **John Clarke** » 11 Apr 2015 12:36 pm

Does anyone know of a remedy for this problem?

Richard Sinkler · Post by **Richard Sinkler** » 11 Apr 2015 1:06 pm

I had a problem like that one time. I contacted Ken Fox about what it might be. i can't remember all that he said, but as I remember, the switch doesn't directly break the power line. It runs through a triac or something. That could be bad. And it was also possible that the the temperature sensor on one of the power transistors was going bad. That would make the amp shut off and on. What I did, was take the chassis out, any connectors that I could remove, I took off and put it back on, especially the lead to the temperature sensor. It somehow solved the problem. That was probably 3years ago, and no problem since. I have the schematics that he sent me if you need them.

Lane Gray · Post by **Lane Gray** » 11 Apr 2015 1:06 pm

I'd replace the switch. Power switches are, over the long run, consumables. They ALL arc on engaging and opening.

Richard Sinkler · Post by **Richard Sinkler** » 11 Apr 2015 1:24 pm

This is a shot of the power in for a NV400. Ken told me he doubted it was a switch problem. More likely the triac or Temp sensor.

Richard Sinkler · Post by **Richard Sinkler** » 11 Apr 2015 2:02 pm

Location of the temp sensor.

The Triac. Riveted into the side of the chassis at the end with the switches.

Eric Philippsen · Post by **Eric Philippsen** » 11 Apr 2015 2:51 pm

I have had Nashville 400's for going on 25 years or so and thought I had seen or heard most of the problems they have. (Still love 'em, though). However, I haven't run into the problem you describe, especially when you say it's happened to three that you've owned. That's really unusual.

My best guess echoes what Richard (and Ken Fox) have said. That is, it's not the power switch but more than likely the Triac or temp sensor.

Richard Sinkler · Post by **Richard Sinkler** » 11 Apr 2015 7:54 pm

My NV400 is an '84 model. Bought it new. The only problem that I have had, that I didn't cause, is this one. And, of course it was right before a gig. Got through set up, tune up, and senseless noodling. Turned it on right at start time and WHAM!! Used another amp the guitar player had until a friend, who was close enough, brought me his Webb to use.

John Clarke · Post by **John Clarke** » 13 Apr 2015 8:51 am

Hey guys, thanks for the information. I'll check it out.

John Clarke · Post by **John Clarke** » 13 Apr 2015 12:38 pm

Thanks a million to Richard Sinkler. I did what he suggested, and now I have a working NV400. I hope it keeps on working. I could have taken a chainsaw to it the other night when it popped on and off a few times then went sayanara. I had to play through a MM210 with the bass and middle full blast and the treble turned down to 2.

Richard Sinkler · Post by **Richard Sinkler** » 13 Apr 2015 6:39 pm

You're welcome. That is a strange problem for sure. It should keep going for a good while.

Jeff Metz Jr. · Post by **Jeff Metz Jr.** » 14 Apr 2015 11:20 pm

Are you gentlemen talking about something other than the amp popping when turned on or off? I have had 2 Nashville 400's that popped everytime I turned them off. Don't recall if they popped when powering up however. I also had a fender Roc Pro 1000 that did this when powered off. Is this a different issue entirely? Thanks

Eric Philippsen · Post by **Eric Philippsen** » 15 Apr 2015 4:26 am

Jeff,

Yes, I think this is a different problem or issue. The one discussed here is where the amp simply stops working, not the "pop" that often occurs in a lot of amps when powered on or off.

Richard Sinkler · Post by **Richard Sinkler** » 15 Apr 2015 7:13 am

My NV400 has always popped, especially when turning on. This problem is actually, your turn on the switch, and without touching your amp again, it turns off, then on, then off, and so on...

Stephen Cowell · Post by **Stephen Cowell** » 15 Apr 2015 4:53 pm

See all the crimp connections? They have no place in an amp supposedly used by professionals. I'm sure that these connections are often the culprit for flakey power on this amp.

Richard Sinkler · Post by **Richard Sinkler** » 15 Apr 2015 5:34 pm

Stephen... I think you are 100% correct.

One good thing came out of this thread for me. It made me remove my chassis to take pics. So, I did the remove and replace these connectors, as well as re-seat the Molex plugs. For a long time now, I had been having a high pitched, barely audible squeal when I would turn the reverb up. I ended up just taking the Molex plug to the tank off, and used my RP155 in the effects loop for reverb. Well, I decided to plug the verb back in, and it works a whole lot better. Peavey's use of these various connectors is their Achilles Heel.