Bias issue on TSL yes I know but this is weird

Discussion in 'Marshall Amps' started by John T, Sep 20, 2019.

  1. mickeydg5

    mickeydg5 Well-Known Member VIP Member

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    People believe these can act like fuses but in reality they just go bad eventually. Higher wattage is good and let the HT fuse(s) do thier job.

    I like the regular HT fuse plus the OT center tap fuse.

    What, wait, you guys do not do that? :)
     
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  2. Dogs of Doom

    Dogs of Doom Moderator Staff Member

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    I should note, that I bought this head used & didn't get much use out of it. I went to change the tubes & ran into this problem, but, since I had also just bought another head, I just used that one & put this one on the back burner...
     
  3. mickeydg5

    mickeydg5 Well-Known Member VIP Member

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    So are you saying this amplifier got jelly and will not work properly because you have other amplifiers?
     
  4. Dogs of Doom

    Dogs of Doom Moderator Staff Member

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    no, I'm just noting that I myself do not have too much history w/ this amp. I bought it, ran into the problem, shelved it & picked up another & moved on.

    Now, w/ this thread, it reminded me of the amp, so, when I went to do some stuff at storage, I grabbed it.

    So, I do not know what happened to it.

    I have maybe 10 hours on it, before I got the new tubes to put in it. So, everything is most likely from the guy before me.

    So, when you ask about a short, or speaker impedance, etc., - not under my watch. If so (possibly) it happened before I got it. The amp runs. I've played it, like it is, but, then shut it down because the bias issue... (didn't want to red-plate them)

    The pots might be bad too.
     
  5. mickeydg5

    mickeydg5 Well-Known Member VIP Member

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    Ok so its a DSL/TSL. Get rid of it and get a better amplifier or the cash.

    I would never buy one in any condition.
     
  6. Dogs of Doom

    Dogs of Doom Moderator Staff Member

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    yes, but I need to fix it before I either sell it, or keep it...
     
  7. mickeydg5

    mickeydg5 Well-Known Member VIP Member

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    I can help with that but you are wasting time. :)

    Just to mention, I will live far longer so the time spent is up to you. :D
     
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  8. jmp45

    jmp45 Well-Known Member

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    Dog, hope you get it sorted it out. Dr. Mick helped me on the rack preamp. Saved me so much time locating the issue. Mick knows his $hit.
     
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  9. mickeydg5

    mickeydg5 Well-Known Member VIP Member

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    Do you people not read my disclaimer/signature? :D
     
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  10. jmp45

    jmp45 Well-Known Member

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    Yeah... I'm ignoring that. :agreed:
     
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  11. Dogs of Doom

    Dogs of Doom Moderator Staff Member

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  12. mickeydg5

    mickeydg5 Well-Known Member VIP Member

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    That is just dropping voltage for the switching. I presume you shorted or something got shorted in the past. Change it out for new one and lets see what transpires.
    Hopefully the condidtion is gone.

    By shorting I mean a bad switcher or cable most likely.
     
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  13. Dogs of Doom

    Dogs of Doom Moderator Staff Member

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    ordered the parts, looks like they come next week...

    thanks!
     
  14. mickeydg5

    mickeydg5 Well-Known Member VIP Member

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  15. mickeydg5

    mickeydg5 Well-Known Member VIP Member

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    You are welcome.
    But just to let you know there are other ways fo diagnose issues.

    I have a life and am watching television with my wife right now. :D
    You know what I mean, I hope.

    If I did charge for support and diagnsotics it would be on the order of $100/hr.
    I like this place and waive my fees. Its pro bono.

    One day that may change.
     
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  16. RickyLee

    RickyLee Well-Known Member VIP Member

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    How much you selling it for DoD?
     
  17. Dogs of Doom

    Dogs of Doom Moderator Staff Member

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    I'm not thinking of selling it as of now...
     
  18. RickyLee

    RickyLee Well-Known Member VIP Member

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    No worries. I need another TSL or DSL like I need a hole in my u no wut.

    Get it sorted out and it will be a fine amp.
     
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  19. Dogs of Doom

    Dogs of Doom Moderator Staff Member

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    not sure what you're asking there...

    My meter is an auto meter, set to ohms. It will automatically add a "k" when it gets to 1,000s.

    I have j-clips. I just put the clips on each side of the resistor, while on the board, not powered up.

    If that's not what you're asking, could you clarify?

    Also, I just pulled the power tubes, & am thinking of putting my meter to do the ampmad diagnostic, measuring to each pin.

    (I need to find his post)

    Quick question, w/ no power tubes, do I need a (speaker) load connected?

    I'm thinking of powering it up & testing each socket, powered (standby) & powered (live), which is what I need to do, right?

    I'm going to go hunt down one of those posts...
     
  20. marshalltsl

    marshalltsl Active Member

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    Maybe this amp has weak connection on the negative pole of the 16 ohms jack output. If you use two 16 ohms cabs with this weak connection happens this things.
    When you do not use the 16 ohm speaker jack, it enable the negative pole connect of the two 4/8 ohm speaker outputs.
     
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