MG Series 100DFX Amp losing volume/power

Discussion in 'The Workbench' started by wintersdawn, May 2, 2010.

  1. wintersdawn

    wintersdawn New Member

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    Hi, I have been having a problem with my 100DFX amp and just came across this forum so thought I would ask if anyone could help me.

    On and off now for quite a long time the volume decides to reduce on the amp by itself, losing power. I then turn it up but when it returns to full volume it blasts out!

    I have tried a different guitar/leads but it definitely seems to be the amp as it still does it. I don't have anything else plugged into the amp just the guitar through the input socket and all the settings are the same as they were prior to this problem starting (the amp is about 6 years old).

    Anyone know why the amp would do this?

    Thanks in advance for any help.
     
  2. wintersdawn

    wintersdawn New Member

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    Can anyone help with this problem?
     
  3. MADDSNIPER

    MADDSNIPER New Member

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    i am having the exact same problem, amp is about 7 years old now and its a MG50DFX

    i also own a v-amp pro which is basically a preamp with effects built in, if i connect into the v-amp and then connect the v-amp into the back of the marshall (bypassing the marshalls preamp stage) then everything works perfectly, but the jack on the front is exactly like the thread starter described. headphone out or speaker out at the back seems clean, using either as output the problem still excists. also the jackin plug looks ok, i opened it all up and checked all the solder on the joints, they seem fine.
     
  4. MADDSNIPER

    MADDSNIPER New Member

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    anyone?
     
  5. Ben C

    Ben C New Member

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    just saw this while searching for problems with MG's losing power...

    try a short jumper cable across the effects loop, a friend of mine had a similar problem with his MG50 combo and doing this solved it!
     
  6. Dogs of Doom

    Dogs of Doom Moderator Staff Member

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    Try spraying contact cleaner on your guitar cable plug (or similar ΒΌ" cable) & make it have sex w/ the input jack. Slide it in/out a good 10-20 x's or so. Probably not a bad idea to do this w/ all your in/out jacks. Then hook everything up & see if that does anything.

    Might be a loose contact @ the input jack.
     
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  7. plec-2

    plec-2 New Member

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    Having seen this fault many times...here's a handy tip..go to the send return jack and use sand paper to shine the contacts or you can left up the leaf part and apply a thin layer of solder to it that way each time the jack lead is removed it will press down it's contact thus better connection. or next one replace new jack sockets..

    3rd tip..is ensure your preamp circuit is working via sending signal out to a next amp..
     

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