• macg1
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  • From: St. Petersburg, FL
  • Registered: 2010-01-21
  • Posts: 1,020

Topic: JCM800 cutting out

So, recently my JCM800 did some strange thing, including at the last show.  It suddenly just cuts out.  If I unplug it from the low sensitivity input, plug it into the high sensitivity input, it starts again, then i can go back to low sensitivity and it works.  A local tech suggested maybe dirty input jacks (it's a 27 year old amp after all), and using the proper cleaner, just spraying into the input and inserting and removing the cable seemed to do the trick when it first happened while recording at the studio, but this live unreliability thing...  Think some more cleaning will do the fix it for good?

Amp: Firebird Musical Amplifiers
Guitars:62 LP SG , 02 FB VII, JB FB I, 76 Electra Omega, 64 Firebird V, 73 LPC, 61 Custom Tele, 59 and 60 Melody Maker
Effects: Mythos Chupacabra, Strymon Deco/Flint
  • Registered: 2008-10-02
  • Posts: 373

Re: JCM800 cutting out

It could be a bunch of stuff, but I would start with a good cleaning, it could also be a cold solder joint. My Jubilee would do this the problem was one of the joints in the effects loop as long as I put a cable in there it was fine. I later had a tech go over it and he fix the problem. I would have a tech look at the amp.

  • Registered: 2011-02-08
  • Posts: 18

Re: JCM800 cutting out

If you have a Tech look at it, have him replace all the old jacks if they are the cause of this.
Cleaning them is only a temporary fix, especially if the metal is starting to corrode

Todd

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  • From: Canterbury
  • Registered: 2010-05-27
  • Posts: 310

Re: JCM800 cutting out

Big E wrote:

It could be a bunch of stuff, but I would start with a good cleaning, it could also be a cold solder joint. My Jubilee would do this the problem was one of the joints in the effects loop as long as I put a cable in there it was fine. I later had a tech go over it and he fix the problem. I would have a tech look at the amp.

Would a cold solder joint suddenly act up?

  • From: Frederick, MD
  • Registered: 2009-03-26
  • Posts: 107

Re: JCM800 cutting out

AndreS wrote:
Big E wrote:

It could be a bunch of stuff, but I would start with a good cleaning, it could also be a cold solder joint. My Jubilee would do this the problem was one of the joints in the effects loop as long as I put a cable in there it was fine. I later had a tech go over it and he fix the problem. I would have a tech look at the amp.

Would a cold solder joint suddenly act up?

A cold solder joint can act up suddenly due to temperature variations inside of the amp.

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  • From: Canterbury
  • Registered: 2010-05-27
  • Posts: 310

Re: JCM800 cutting out

Oh....I see...

I did not know that.

  • macg1
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  • From: St. Petersburg, FL
  • Registered: 2010-01-21
  • Posts: 1,020

Re: JCM800 cutting out

thanks for the advice guys!

Amp: Firebird Musical Amplifiers
Guitars:62 LP SG , 02 FB VII, JB FB I, 76 Electra Omega, 64 Firebird V, 73 LPC, 61 Custom Tele, 59 and 60 Melody Maker
Effects: Mythos Chupacabra, Strymon Deco/Flint