Help with Nashville 400

Cliff Kane · From: the late great golden state

Hi Folks,
I could use some advice from people familiar with these amps. I just bought a used Nashville 400, serial #CC870758, for what seemed like a pretty good deal, and it sounds good except for a major problem that has developed: Sometimes the amp makes an incredibly loud bang/buzz--it actually sounds like a shotgun blast, it's so loud. This is intermittent: it does this when my steel is playing through the amp; it does this when switching the amp on with the controls up and the steel plugged in; and it does this when switching the amp on with all the controls (including the gains controls) down and no guitar cord plugged in to the amp. The only other thing that the amp does that seems related is that when switching the amp on (when the super loud bang/buzz doesn't happen) there is usualy a popping sound from the switch (sounds like static build-up, but hapens everytime). This amp sounds good, and otherwise seems fine, but I'm afraid to even turn it on for fear of blowing the speaker or being evicted from my home (by either the wife or the landlord). I would really appreciate any help folks can offer for this problem: I'm hoping that it's not a major problem.

Thanks,
Cliff

Jack Stoner · From: Kansas City, MO

It sounds like the infamous reverb I/O connector problem. The next time it does it turn the reverb down to zero and see if it goes away. If it does, there's a 99.9% chance it's the Molex connector. Sometimes you can fix it by just "reseating" the connector - unplug it and then plug it back in. For a longer fix unplug it and spray contact cleaner of both the male pins and the female pins in the connector and then plug it back in. In extreme cases one of the female pins may not be making good mechanical contact and it will have to be VERY CAREFULLY bent slightly to make the female smaller.

It it's not the reverb, check the pots and one may be dirty.

Cliff Kane · From: the late great golden state

Jack--thanks for your reply. I hope that's all it is. I tried to pull the IO connector, but it doesn't want to come out easily, and I don't want to force it--does it just pull straight out? Any way, I'll exercise it as you advice. However, this happens with the reverb (and all other controls) turned all the way down. The pots are not scratchy sounding, and also it hasn't happened when turning any knobs, so I have a feeling that it's not connected to pots. It is like a full-volume (really really painfully loud!) buzz. Would the reverb IO connector problem cause the amp to generate a full-volume buzz, regardless if signal is going through the amp (such as when first switching it on), a steel is being played through it, or all knobs are turned down and no guitar cable is plugged into the input (this is the trouble shooting that I've done)? The amp hasn't done it the last few times I've played it, but there is a fairly loud "POP" when first switching the amp on after it has sat turned off for awhile; is this normal with these amps? I'm a little gun-shy of turning this amp on, as I don't want to blow the speaker, and I'm also nervous about using it to play out, as this would be a disaster on stage or with a band. Thanks for your help; sorry for ranting a little, but I'm bummed that what I thought would be a dependable steel amp has become a bit of a dicey proposition.

Thanks again,
Cliff

Craig A Davidson · From: Wisconsin Rapids, Wisconsin USA

On a Bandit I had once, I had that problem and it turned out that a couple caps on the inside had come undone. When noise went through the amp it vibrated and they arced on the board. I soldered them back and never had any more trouble. My twin did the same thing. In the Peavey I thought it was the verb too. Then it did it once after the verb was off. Bingo I found it. If you are real careful you can fix it yourself. If you are nervous around voltage take it to a Peavey repairman.

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[This message was edited by Craig A Davidson on 28 April 2001 at 09:14 PM.]

Blake Hawkins · From: Florida

The "pop" when turning the amp on is normal for these amps. We've had several threads on this in the past.
I checked mine with a 'scope and it looks like the pop is caused by the filter and/or bypass caps on the +52 volt power supply charging when the amp is first turned on.
If you listen carefully you can hear a faint pop when you turn the amp off as the caps discharge.
It won't hurt anything.
Blake

Bill Terry · From: Bastrop, TX

There was a long post a while back on this topic. My Nashville did that for a while and I finally found a broken solder joint on one of the pots where it is mounted to the PCB. It created a huge pop when you tapped the control from the front.

You could tap around on the outside of the amp with it powered up and see if you can trigger the pop, if so it's likely to be a mechanical problem, broken solder joint, dangling part, etc.

If you're technical you can open up the amp and with power on, and tap around lightly inside the chassis on the PCB with some non-conductive device like the eraser end of a pencil. Light taps should let you locate the vicinity of the problem, but you may need a magnifying glass to actually see cracked solder joints.

If you're not TOTALLY comfortable poking around inside an amp with the power on have a tech look at it.

BTW, all of this is hypothetical, you may have a different problem, but that's very similar to the symptoms my amp had.

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Mike Brown · From: Meridian, Mississippi USA

The turn on transient problem that you mentioned could be caused by defective DVL caps or unstable connections on the filter caps. I highly recommend that you allow a qualified technician to test the amp for you to determine the solution.

I can be reached toll free in the U.S. at 1-877-732-8391 should you wish to discuss. You may also locate your nearest authorized Peavey repair center on our website at www.peavey.com If I can be of further assistance, please feel free to contact me at the factory.

Cliff Kane · From: the late great golden state

Thanks everyone for your helpful and informative replies. After some healthy exercising of that molex reverb connector I haven't had any more problems, and I can't seem to recreate the problem, which is good, but also leaves a little uncertainty about the source, although I suspect the molex conector may be the culprit. Great help all around, thanks again. What a great forum this is! I'm going to bring this amp into a service center to have it looked over anyways, as it's probably pretty old and might need a check-up, but so far so good.

Best regards,
Cliff

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