Nashville 1000 problem

Dick Wood · From: Springtown Texas, USA

My 1000 has been having what appears to be an intermittent short. It's worse when I turn on the amp and get's better after it has been on a little while. I will be playing and it starts to break up and then no output at all until I increase the volume pedal and pick the strings hard which causes it to come back on for a few minutes.

I have checked all cables,used Deoxit on the jacks, changed volume pedals and played direct and it still does it.

I took the chassis out and looked for anything that might be loose or maybe a bad solder joint but see nothing obvious.

Maybe one of you has experienced something like this and could comment on what you found wrong.
_________________
Cops aren't paid much so I steel at night.

Jack Stoner · From: Kansas City, MO

A Bad "Normal Through" jack contact could be the culprit. There are three possibilities, the Pre EQ patch, the Post EQ patch and the Preamp Out/Power Amp In.

The next time it does it, connect a guitar cable from the Pre EQ patch out to the Pre EQ patch In. If that fixes it the "normal through" contact on the Pre EQ IN jack is the problem. If that doesn't help do the same thing to the Post EQ patch and if that doesn't help do the same thing to the Preamp Out/Power Amp in. One of the three are a likely candidate for the problem. There could be another internal amp problem but the jacks are often the problem.

Stephen Cowell · From: Round Rock, Texas, USA

You have to clean the switching contacts of the jacks... this is not easy (or maybe even possible) on enclosed jacks. Best is a piece of business card with De-Oxit on it... get it between the contacts and rub it back and forth for a few seconds. You can't just spray the stuff in there, it needs help.

There are also Molex connectors in the amp that can get dirty... it's probably time for a complete bench maintenance. See a tech if you aren't one yourself.
_________________
Too much junk to list... always getting more.

Dick Wood · From: Springtown Texas, USA

Thanks for the tips but it is still doing it.

Here's something I noticed. I can be playing at a good volume and if I back of the pedal slowly until there's almost no volume,the problem pops up until I increase the volume and pick the strings pretty hard.

The intermittent volume pops up at any volume level but does seem to be more frequent as I back off the pedal.

As much as I hate it,looks like a trip to Peavey.
_________________
Cops aren't paid much so I steel at night.

Jim Eller · From: Kodak, TN (Michigan transplant)

Question:

Which DeoxIT do you use for this application? I see it comes in D, G, S and F series.

Thanks.

Dick Wood · From: Springtown Texas, USA

Hi Jim, the can says GS on it.
_________________
Cops aren't paid much so I steel at night.

Ken Fox · From: Nashville GA USA

In the past I've fixed several amps with this problem. The problem was on the main power amp board. There's a large red female push on connector in the middle of the board and the stake pins underneath the board had cold solder joints.

Dick Wood · From: Springtown Texas, USA

Hi Ken,That may be the area because last night I had the chassis out and I'd hit a note and let it sustain then the note would get kinda fuzzy as it decayed and then it would go dead.

I took a Bic pen and started tapping the various boards and that board got the most response when I tapped it.

I will take it out and see if there are any cold solder joints on it.

Thanks
_________________
Cops aren't paid much so I steel at night.

Dick Wood · From: Springtown Texas, USA

Well I guess I'm whooped. I took out every board. Using a magnifying glass and bright light I found two questionable solder joints which I re-soldered but no joy.

It did work great for about 20 minutes then started doing it again.

If anyone wants to buy this amp (which looks brand new) and a flight case which is also looks new then drop me a line.
_________________
Cops aren't paid much so I steel at night.

Jack Stoner · From: Kansas City, MO

I would "reheat" the pins that Ken Fox mentioned.

Also, with a PC board the actual joint may be OK but there may be a hairline crack in a trace causing problems. I found that on my Nashville 400 reverb. One of the traces about an inch away from one of the motherboard Molex pins had a hairline crack and was causing intermittent problems.

Dick Wood · From: Springtown Texas, USA

Here's the latest,rechecked and soldered anything that even remotely looked suspicious.

Played with/without pedal,used jumpers on pre and post EQ patches. All cables were tested for shorts or opens and all checked good.

I even used the speaker in a Nashville 400 just encase it might be the speaker in the 1000 and THE INTERMITTENT SHORT IS ALIVE AND WELL.

The weird thing is,is that if I play loud everything is pretty much ok but if I reduce the volume slowly, at a certain point the problem shows up.

It's going to the shop.
_________________
Cops aren't paid much so I steel at night.

Jack Stoner · From: Kansas City, MO

Dick Wood · From: Springtown Texas, USA

Jack, Yep,I did that too.It sure acts like a connection issue but maybe a component trying to go bad.
_________________
Cops aren't paid much so I steel at night.

Jack Stoner · From: Kansas City, MO

Did you (lightly) push down on the IC chips on the preamp board to "seat" them?

I wouldn't give up yet, but then I'm an ex amp tech.

If you have another amp, run the Preamp Out from this amp to the Power Amp in on another amp and see what happens. Will help to isolate where the problem is.

Dick Wood · From: Springtown Texas, USA

I did push each IC down and I wiggled everything on each board trying to see if a component was loose,flaky etc.

I do have a Nashville 400 that works great so I'll try your idea and see what happens.

Thanks for all your help along with the others that have responded.
_________________
Cops aren't paid much so I steel at night.

Forum Index > Electronics		Next oldest topic :: Next newest topic

All times are GMT - 8 Hours	Jump to: