DSL sound cutting out

Discussion in 'Marshall Amps' started by Mjojo51, Jun 23, 2019.

  1. Mjojo51

    Mjojo51 New Member

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    Dsl40c sound has cut out a couple times and had to turn off and on to reset. Think it may be a relay somewhere. . Anyone that's had this problem and narrowed it down please let me know.
     
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  2. AlanH

    AlanH Well-Known Member

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    I had a few cutting problems with mine in rehearsal situations and eventually put it down to vibrating tubes at higher volumes and some poor quality guitar and patch cables. I ended up buying some electrician's grommets from eBay for the other three preamp tubes and getting better leads and patch cables.

    Rule these out first if you haven't already.
     
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  3. Len

    Len Well-Known Member

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    Do they fade out, or cut out? Fade out might be bad tubes.
     
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  4. Michael Roe

    Michael Roe Well-Known Member

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    JJ power tubes?
     
  5. Mitchell Pearrow

    Mitchell Pearrow Well-Known Member

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    :welcome: To the forum
    I have not had that problem, but I am sure it will be addressed in your thread here
     
  6. ampmadscientist

    ampmadscientist Well-Known Member

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    1. Buy 1 new 12AX7 tube and swap the tubes out one at a time.
    Retest each time you swap 1 with the new one.

    2. Plug a guitar cable between send and return, then re-test. Do this with no effects connected.

    These are 2 of the most common causes of cut-out in guitar amps.

    3. It is probably not a bad power tube which makes an amp cut out completely.....and there is nothing wrong in general with JJ tubes either.
     
  7. Mjojo51

    Mjojo51 New Member

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    Thanks for the responses but its not tubes or fx loop jack problems. Also when turning amp on occasionally if I don't hear the eternal relay switch click after hitting the on switch it does the same thing ( no sound ) and have turn amp off and on then it fine. Just wondering if anyone has had this issue and which relay in the circuit it would be that's possibly bad. Thanks
     
  8. Michael Roe

    Michael Roe Well-Known Member

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    You are wrong on this or my amp tech lied to me! Not likely, read on...….My DSL head was cutting out and the problem was solved by replacing the arching JJ power tubes. The amp tech didn't replace them either, I did. He just identified the problem and I said, oh, well I have an extra set of Svetlana I will use them. Done! problem fixed.
     
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  9. Mjojo51

    Mjojo51 New Member

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    sorry but your bad tube issue isn't what's causing my problem
    Already replaced all tubes and problem existed before and after new and tested tubes were installed. Only acts up randomly like once a week so it hard to check results with anything suggested so far. I'll have to open it up and check for bad solder joints or connections somewhere. Beyond that its hard to find a intermittent component failure if that's the problem. Thanks
     
    Last edited: Jun 24, 2019
  10. Mjojo51

    Mjojo51 New Member

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    Couldn't find any bad solder joints after probing and inspecting everything . Guess there's no actual Tech's out there that have come across this issue so I'll have to live with it till it cuts out permanently to be able to trace it down. Thanks to those offered suggestions.
     
  11. ampmadscientist

    ampmadscientist Well-Known Member

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    Arcing tubes could be caused by an impedance mismatch, or possibly shipping damage.
     
  12. scozz

    scozz Well-Known Member

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    That’s very interesting @ampmadscientist, would you please explain the reason for connecting a cable between send and return in the effect loop? (No pedals involved)
     
  13. ampmadscientist

    ampmadscientist Well-Known Member

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    No, don't play the amp, and continue troubleshooting.
    It is a bad idea to play the amp right now.
    Open the amp up and inspect the tube sockets.
    Look for any parts that may have broken loose from the circuit board...

    Possible issue bad speaker jack. broken solder connection on input jack.
     
    Last edited: Jul 5, 2019
  14. ampmadscientist

    ampmadscientist Well-Known Member

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    The effects jacks have switches internally.
    The signal path of the amp goes through, and depends on these switch contacts.
    When the switch contact gets oxidized or damaged the amp will stop working.
    Connecting send to return with a cable bypasses these switch contacts.
    If the amp works after bypassing, replace the effects loop jacks (cleaning is usually temporary but may cause the switches to work again).
    It is always better to replace jacks than just cleaning on an old amp....for reliability anyway.
     
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  15. scozz

    scozz Well-Known Member

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  16. Mjojo51

    Mjojo51 New Member

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    Thanks for your Input I already tried jumping the loop and it doesn't solve problem. I've deal with Jack issues before and already checked out basic causes first. Its my only amp so I'm not going to stop using it. I've done a!l my amp repairs for many years and will eventually figure it out and If it dies before that and isn't repairable I'll just buy another one as needed. Thanks
     

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