Need help installing PT for DSL100. UPDATED 8 YEARS LATER!

Discussion in 'The Workbench' started by American Viking, Feb 29, 2012.

  1. American Viking

    American Viking Well-Known Member

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    Trying to replace a power transformer in a JCM2000 DSL100. Problem is I can't find any info on what voltage wires go to what part of the board. I looked up the schematics for the amp and they only show you where the heater wires go. That's a no brainer anyway but they don't show anything else.

    I have specs on the new transformer but not for the original or the amp itself. If anyone could hook me up as to tell me which wire or voltage goes to the spots W7, W10 etc etc on the tube board and AC in board I would much appreciate it. Thanks in advance.

    BTW, couldn't test the voltages on the original PT because it was shot.
     
    Last edited: Mar 1, 2012
  2. LBKENNEDY

    LBKENNEDY New Member

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    probably sling a cat to the city limits of knoxvil
    dude can you read a schematic diagram if so ther is your answer, if not dont guess find a tech.
    if this doesnt point you get back up here happtra lbk
     
  3. LBKENNEDY

    LBKENNEDY New Member

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    probably sling a cat to the city limits of knoxvil
    excuse me i think i remember what your talking about now. there are a lot of
    dsl 100 prints on the internet that do not show what you are asking for
    if you cant find the standby switch wiring and bias winding input points clearly
    on your print you probably have those incomplete ones
    the dsl power supplies represent a departue from the old style, againbe careful
    and if you aint happy call back happtra lbk
     
  4. American Viking

    American Viking Well-Known Member

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    Here is some more info.

    This is an image I made from where the original PT came out. Another thing that messes me up is that the board says JCM2-60-00 but the schematic for that board says the heaters go to W6 and W7 but I swear on this amp they go to W9 and W10. I could be wrong.

    If someone could tell me the correct voltages for these wires this would infinitely help me out. Again, I looked at some schematics but I can't find any specifics on this.

    I've got an amp just sitting here DOA and all it's going to take is a few minutes with a soldering iron along with some good info. Pretty depressing.

    Thanks!

    [​IMG]
     
  5. mickeydg5

    mickeydg5 Well-Known Member

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    Dude, I thinkl you may need to look at the newer revision version JCM2-60-02 issue #7. Marshall messed up on schematics changing and using redundant numbers.

    http://www.drtube.com/schematics/marshall/jcm2-60-02.pdf

    Always trace you wires to make sure they connect to the right stuff, good practice.
     
  6. American Viking

    American Viking Well-Known Member

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    That's still not showing me where all the wires go or what voltage the wires are...
     
  7. mickeydg5

    mickeydg5 Well-Known Member

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    AV, I did not abandon you. I am looking over the schematics. All found on www.drtube.com for the DSL100 later revisions.

    Questions on your diagram:
    The brown W7, might that have been a W9? Old and new version show W9.
    Can you describe what the yellow W10 connects to including downstream components? It is not totaly clear on the schematics and this would help.
     
  8. mickeydg5

    mickeydg5 Well-Known Member

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    Ah, another big help and some good information.
    What replacement PT do you have so that I can find a diagram on it?
     
  9. American Viking

    American Viking Well-Known Member

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    This weekend I can tell you which positions go down stream to the other parts, I just have to get back in front of the amp. Maybe tomorrow if I get a chance.

    I'll double check on that brown wire.

    I have a ClassicTone PT for it. That spec is here http://www.classictone.net/40-18084.pdf
    I just don't know what the old values were to replace like for like.
     
  10. mickeydg5

    mickeydg5 Well-Known Member

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    That is the PT I was referencing. I figured you might have choose that one.
    We will run this down and figure it out. The ClassicTone will have a couple of terminated (unused) leads.
     
  11. American Viking

    American Viking Well-Known Member

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    Ah, I did not know that.

    Hey man, thanks so much for your help!
     
  12. mickeydg5

    mickeydg5 Well-Known Member

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    Well, only one wire will not get used from the ClassicTone. That is the green/yellow heater C.T.
    We just need to verify those other questions. I believe the brown should have been to W9 (primary feed) and the yellow should have been towards W6 and the standby switch according to the drawings.

    And, you are welcome.
     
  13. Lane Sparber

    Lane Sparber Well-Known Member VIP Member

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    AV - Just for old time's sake, I believe I can help you here with your PT secondary windings.

    First, it's absolutely CRUCIAL to know which circuit board revisions you have. To determine what's what in your own amp, please go here:

    Marshall DSL

    Scroll to the bottom and our own JCMJMP will guide you through the process. For the most part, the wire numbers didn't change throughout the revision process, but let's be sure what we're working with before proceeding. Remember, different revision numbers for different boards can be inside the same amp. For example, my own personal DSL has Revision 1 boards for everything EXCEPT the tube board, which is a Revision 3 model!

    From what you've posted, it seems you have a later revision of the circuit. Assuming you do, let's work off of the revision 7 board on Dr. Tube's site:

    http://www.drtube.com/schematics/marshall/jcm2-60-02.pdf

    So, we can clearly see that your new green 6.3v heater secondary wires connect to W9 and W10 on the tube board. You can double check this by making sure that W10 has continuity to R78, and W9 has continuity to R8. R78 and R8, by the way, are the 100 ohm false center tap resistors for the heater string. From there the path leads to the heaters of V4-V7, and you can check this also. The green/yellow wire, as Mickey said, is unused here, and for the record, the original wires should have been red.

    W11, W12, and W13 are for the low voltage secondary (22-0-22 - drawn as 0 and 43v on the Classic Tone page) inlet. This would be the two white and one blue wire on your transformer. The blue wire is the center tap, and it goes to W12. You can verify THIS because W12 should have continuity to ground. W11 and W13 are for the outer windings of this secondary - the two white wires. W11 should have continuity to C43, and W14 should have continuity to C44. C43 and C44 are the two blue 22uf 50v bipolar caps used in the clamped voltage doubler to the bias supply. If you want to check further, W11 should ALSO have continuity to PIN 1 of CON 14, and W13 should also have continuity to PIN 3 of CON 14. CON 14 is what carries the un-rectified voltage from this secondary winding to the rear board, where it is rectified and adjusted to feed the op-amps in the FX loop, reverb and "Deep" switch circuits (and it also feeds the relay switches from there).

    That leaves the B+ secondary. One red wire goes to W7 on the tube board, and it should initially have been a purple wire. W7 should have continuity to D4, D6 and C41 on said tube board. The other wire, as you have on your home-made diagram, goes to W10 on the power inlet board. Then it goes to the standby switch via yellow wire W11, and back FROM the standby switch via yellow wire W15. After running through the HT fuse, this path re-enters the other half of the FWB rectifier circuit on the tube board via the pink wire at W6 (on the tube board) from power inlet board W15.

    See handy pic attached! :D

    [​IMG]

    The DSL and TSL family of amps are VERY tricky to work on due to the complexity of the circuit and the silly way the schematics are drawn...not to mention the countless revisions over the years. This is why I've illustrated where the current is going in addition to the simple wire numbers for each secondary winding. This way, even if the wire (W) numbers I mention don't jibe with your boards, you'll still know enough to hopefully find your own way and deduce what's what on your own. It goes without saying that to really troubleshoot THESE amps, you've gotta know your stuff! I'm still working on the "know your stuff" aspect myself, and it's a never ending journey - there's ALWAYS more to learn! :)

    I hope this helps you! :cheers:

    -Lane
     
    Last edited: Mar 2, 2012
  14. mickeydg5

    mickeydg5 Well-Known Member

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    Again, some good information Lane.
    Yeah, I really don't like how some companies illustrate their schematics. The fact that they arbitrarilyy change things and move numbers around is aggravating. Having different revisions and issue boards within the same amplifier makes it even more complex. That is why I like to trace wires and runs to make sure everything is connecting to the right place. Always better safe than sorry.
     
  15. Lane Sparber

    Lane Sparber Well-Known Member VIP Member

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    Not to be contrarian, Mickey, but in the case of the DSL, the changes were anything but arbitrary. Filtering was changed and improved, an LDR was replaced with a relay, and other components were changed for the better.

    This I agree wholeheartedly with, and since AV seems to be serious about working on amplifiers, that's the direction in which I'm trying to point him through my post above. In many ways, as previously stated, working on a DSL most often requires that the less experienced or budding tech up one's game a bit. :)

    -Lane
     
  16. mickeydg5

    mickeydg5 Well-Known Member

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    Sorry for any confusion. I did not mean I had a problem with the design and component revisions. My problem is with the general layout and the handling of revisions on the drawings.

    I like a better mouse trap. Just please consistently illustrate it without adding confusion.
     
  17. Lane Sparber

    Lane Sparber Well-Known Member VIP Member

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    LOL! I hear ya. However, given the way the drawings were originally generated, there really WAS no better way to handle the revisions short of a complete redrawing of the entire amp. I think that you and I BOTH know that THAT was never gonna happen. ;)

    -Lane
     
  18. LBKENNEDY

    LBKENNEDY New Member

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    probably sling a cat to the city limits of knoxvil
    way to go sparb
     
  19. American Viking

    American Viking Well-Known Member

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    Exactly. I was able to run by my space and check it out on the way home. Couldn't stay too long but that brown wire was bundled in with some other ones. I was rushing and notated the wrong one.

    Thanks Lane and Mickey, this is going to help me out a lot. I'm going to wire this bad boy up first chance I get this weekend.

    Too bad you can't really use this as a slave or power amp since plugging into the effects return negates any volume control. Wonder if a PPIMV has ever been implemented on this thing or if all that is really worth the trouble. Eh, just a thought. One thing at a time... Get 'er working first!

    Thanks again.
     
  20. mickeydg5

    mickeydg5 Well-Known Member

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    I have put this together.
    Always verify your "W" connections. There seems to be an awful lot of descrepancy between different version amps and boards. Again trace wires to adjacent components to be sure of things. Any questions, ask.

    Provide pictures of your connections and boards if possible.

    Lane's description and pictures along with my attachment are using later revision and issue boards. We have to establish whether or not your amp and board component numbers match up. All of the compnent numbers may not match but the parts and placement should be the same.

    DSL100 PT stock to ClassicTone wiring small.jpg
     
    Last edited: Mar 3, 2012

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