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  1. I'd get it running (if transformers ok) and use...

    I'd get it running (if transformers ok) and use it with pedals if you find it sounds too flat.
    Start with checking power supply and tube DC voltages.
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    I think you are talking about testing the...

    I think you are talking about testing the transistors with diode check in circuit but unpowered.
    If so, you can not expect them to test the same as out of circuit.
  3. I hate to say it, but I'd try it with TR1...

    I hate to say it, but I'd try it with TR1 removed. If the Led still won't go off, you may have some board leakage.
    But if you see any residue around, clean it up with isopropyl and try again before...
  4. Can you post the emitter and collector voltages...

    Can you post the emitter and collector voltages for TR1 with channel off and on?
  5. If you are still on the bulb limiter you can't...

    If you are still on the bulb limiter you can't expect the numbers that are called out on the schematic. Was the protect bulb ever lit while on the bulb limiter?
    Do you have the speakers...
  6. By sub'd do you mean you replaced TR1? A diode...

    By sub'd do you mean you replaced TR1?
    A diode test may not find leakage.
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    You're up against a bit of a wall here. You...

    You're up against a bit of a wall here. You don't know what oscillation looks like on a scope, but there is also the problem that the oscillation may be strictly acoustic feedback that will only...
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    Typo, you mean C47 not R47 here. I wasn't...

    Typo, you mean C47 not R47 here.

    I wasn't understanding why the reverb mod until I looked at the M581 schem. from post #8.
    It looks like the newer models like in the 2015 schem. from same post...
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    Preamp tubes themselves are probably the most...

    Preamp tubes themselves are probably the most common cause of feedback. While it is occurring hold them with a rag (or something to prevent burns) one at a time to see if anything affects the...
  10. So the red Led (LED2) is the one that won't turn...

    So the red Led (LED2) is the one that won't turn all the way off? If so, with the TR1 voltages you measured, TR1 must be leaky.
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    Also C7.

    Also C7.
  12. Sorry, no suggestions for the notch filter. But...

    Sorry, no suggestions for the notch filter.
    But Q5 base is measuring pretty much a double diode drop from B+ ?
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    I don't see that anywhere on the schematic you...

    I don't see that anywhere on the schematic you posted? :confused:
    The relay or the switch could still be intermittent. Or a shaky solder connection.
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    Set your meter to resistance. Put one probe on...

    Set your meter to resistance. Put one probe on each speaker terminal, + and - doesn't matter for this. Resistance should probably measure somewhere in the 8 to 40 ohms range. If necessary do the...
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    Sticky: I found out there is an option, when firefox...

    I found out there is an option, when firefox starts, instead of showing homepage, you can choose 'show my windows and tabs from last time'.
    So you can close firefox with tabs open, and next time you...
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    Sticky: I bought a refurb windows 7 machine last winter. ...

    I bought a refurb windows 7 machine last winter. I've yet to migrate over to it.
    I guess I've been waiting for support to end for 7, then I'll feel ok about it. ;)
    I have about 30 Firefox tabs...
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    The troubleshooting in the first post made me...

    The troubleshooting in the first post made me think it's the actual speaker in the right side that is bad.
    Receiving signal, no sound.
    Have you tried measuring resistance at the right speaker...
  18. Thread: Desktop Wallpaper!

    by g1
    Replies
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    329

    I like the scenic ones too. Mine is just a...

    I like the scenic ones too. Mine is just a generic one from the 'vistas' section of the desktop backgrounds in windows vista.
    It's actually a Japanese hillside reflecting in a lake I think.
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    You must have all tubes in circuit to check...

    You must have all tubes in circuit to check voltage. If any of V4 - V7 are removed, no tube should light up.
    If all of V1,V2, and V3 are not installed, you could get a result like you are...
  20. Thread: Dual tap OT quandry

    by g1
    Replies
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    You're going to be busy for awhile. :D

    You're going to be busy for awhile. :D
  21. One thing I'll mention is I was surprised to see...

    One thing I'll mention is I was surprised to see so many ECB pinouts in this unit when I'm used to seeing EBC on 2N types.
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    A Fender branded 5Y3 could very well be made by...

    A Fender branded 5Y3 could very well be made by sovtek. If so, they will visibly be very similar.
    Hope you have better luck with the TAD.
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    I wonder if those examples aren't using those DC...

    I wonder if those examples aren't using those DC heater supplies for other things as well, resulting in a need for the ground reference?

    edit: I see Merlin does speak of shorting out the...
  24. My transistors are: Q1,2,4, 2N3416 All others...

    My transistors are:
    Q1,2,4, 2N3416
    All others stamped with Heathkit numbers from parts list.
    Q3 & 5 plastic TO-99, Q6,7,8, small cans as shown in wave gen. pictorial (#10)
    Q10 as shown in...
  25. Doesn't seem to be an issue for you, but my unit...

    Doesn't seem to be an issue for you, but my unit had problems with the trim pots. There was LF modulation of the output which I was pretty sure must be a bad cap issue, but turned out to be that the...
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    You are on the bulb limiter? Do not use math...

    You are on the bulb limiter? Do not use math based on 32V total for heaters, measure it. What is the DCV across C211?
    Measure each power tube from pin 2 to pin 7, not to ground. Measure pin 4 to...
  27. Thread: Dual tap OT quandry

    by g1
    Replies
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    This is a little anecdote I've shared before, but...

    This is a little anecdote I've shared before, but it is possible the diode got implemented for this reason and just got continued on because 'that's how we do it now'.

    This first mass-produced...
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    So it turned out the resistor was getting it's AC...

    So it turned out the resistor was getting it's AC source from the PT secondary like in this schematic?
    And you were missing the ground between the LED cathode and the 1nF ?
    I'm going to guess...
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