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Thread: PL20 REV C board capacitors C3L & C3E went POOF

  1. #11
    Forum Veteran 62vauxhall's Avatar
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    No such things as bad days, just bad moments
    Seems I smoked a couple of resistors too, just for good measure.

    Thanks G for the parts list. Mouser has on hand all but one which is Q2 - MJE15033G. They show the ship date for new stock as 2017-09-04. That could mean September 4th or April 9th and they're late.

    But Digikey have them and I believe I saw Q1 - MJE15032G as being on hand as well. Would obviously prefer to order everything from the same supplier but it is too late at night right now for me to start checking Digikey for all parts. I have 4 hours to sleep and I want all of it.

    If Q1 & Q2 are to matched to less than or equal to 500uV Vbe, will a supplier do that? I don't relish the thought of buying a bunch of each and hope that two are close enough. Plus, I have no device that makes that measurement.

  2. #12
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    Halfbiass...Electron Herder and Backass Woof
    You do not need to match Q1,Q2. They drop the voltage from 80 to 20, then the TL-431, TO-92'S regulate the voltage.
    taking something that's already good, and making it better...........and for the knowing smiles that cross their faces.......Nando-2011...

    "Silence cannot be Misquoted"--Lazarus Short-2012 "

    " I Just Collect Smiles Craig......Cheap Smiles!-----Fishoz-2017

    "anything can be done, it's finding the easiest way that's hard"-----Bobbysdad--2014

    " Synth percussion is deadly to children, house pets and shitty power supplies"---Stephen Evans 2014

    " You have not reached the point of diminishing returns, you've just ran out of money

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  3. #13
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    Halfbiass...Electron Herder and Backass Woof
    Check the diodes in that section too.
    taking something that's already good, and making it better...........and for the knowing smiles that cross their faces.......Nando-2011...

    "Silence cannot be Misquoted"--Lazarus Short-2012 "

    " I Just Collect Smiles Craig......Cheap Smiles!-----Fishoz-2017

    "anything can be done, it's finding the easiest way that's hard"-----Bobbysdad--2014

    " Synth percussion is deadly to children, house pets and shitty power supplies"---Stephen Evans 2014

    " You have not reached the point of diminishing returns, you've just ran out of money

    " The Pioneer U-24, unfortunately, is just too expensive and rare to find. That's why I have one."--Nando-2014

  4. #14
    Forum Veteran 62vauxhall's Avatar
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    No such things as bad days, just bad moments
    The Digikey site is all but impossible to access via my phone. Too big, won't completely load then I get punted off.

    I since learned on the Mouser site (which does load) that their part #512-TL431CLP is obsolete so it's in my interest to get all from Digikey.

    They don't seem to carry Xicon resistors but I assume they'll have 10 ohm & 22 ohm 1% metal films by someone else.

    Parts list did not say (or I did not see) - 1/2 watt....1watt?

    Lee, regarding the diodes. I was reading through Rocuss's 400 thread. Seems to have been something similar going on. So it's the Zener's @ D80 & D81 I'm to inspect? There are a multitude of IN4148 / 49 in the neighbourhood but I have a quantity on hand.

    I believe once before you advised diode checking in circuit is sufficient to determine dead or alive? To recap, is that done in DMM diode check mode with the power caps discharged or does one leg need to be pulled?

    Would not look forward to multiple diode testing in that manner with this type of board. Had that bad experience before changing relays on a speaker protect board with those through hole sleeves.

  5. #15
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    Halfbiass...Electron Herder and Backass Woof
    D80, D81 are Zeners, a 1N4148 IS NOT, do not sub that. In circuit is OK for the dead or alive test. Meter in diode check mode, caps discharged and amp powered down...
    taking something that's already good, and making it better...........and for the knowing smiles that cross their faces.......Nando-2011...

    "Silence cannot be Misquoted"--Lazarus Short-2012 "

    " I Just Collect Smiles Craig......Cheap Smiles!-----Fishoz-2017

    "anything can be done, it's finding the easiest way that's hard"-----Bobbysdad--2014

    " Synth percussion is deadly to children, house pets and shitty power supplies"---Stephen Evans 2014

    " You have not reached the point of diminishing returns, you've just ran out of money

    " The Pioneer U-24, unfortunately, is just too expensive and rare to find. That's why I have one."--Nando-2014

  6. #16
    Forum Veteran 62vauxhall's Avatar
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    No such things as bad days, just bad moments
    Yes, understood. Only mentioned the non-Zener standard diodes because some are in/near the affected area.

    EDIT: Was planning to include some of those Zener diodes with what I order from Digikey. But IF I needed IN4148/IN4149 for direct replacement, I have those. Would not attempt to substitute non-Zener for Zener.
    Last edited by 62vauxhall; 05-30-2017 at 07:21 PM.

  7. #17
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    Halfbiass...Electron Herder and Backass Woof
    Understand Gary....
    taking something that's already good, and making it better...........and for the knowing smiles that cross their faces.......Nando-2011...

    "Silence cannot be Misquoted"--Lazarus Short-2012 "

    " I Just Collect Smiles Craig......Cheap Smiles!-----Fishoz-2017

    "anything can be done, it's finding the easiest way that's hard"-----Bobbysdad--2014

    " Synth percussion is deadly to children, house pets and shitty power supplies"---Stephen Evans 2014

    " You have not reached the point of diminishing returns, you've just ran out of money

    " The Pioneer U-24, unfortunately, is just too expensive and rare to find. That's why I have one."--Nando-2014

  8. #18
    Administrator Gepetto's Avatar
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    Quote Originally Posted by 62vauxhall View Post
    The Digikey site is all but impossible to access via my phone. Too big, won't completely load then I get punted off.

    I since learned on the Mouser site (which does load) that their part #512-TL431CLP is obsolete so it's in my interest to get all from Digikey.

    They don't seem to carry Xicon resistors but I assume they'll have 10 ohm & 22 ohm 1% metal films by someone else.

    Parts list did not say (or I did not see) - 1/2 watt....1watt?

    Lee, regarding the diodes. I was reading through Rocuss's 400 thread. Seems to have been something similar going on. So it's the Zener's @ D80 & D81 I'm to inspect? There are a multitude of IN4148 / 49 in the neighbourhood but I have a quantity on hand.

    I believe once before you advised diode checking in circuit is sufficient to determine dead or alive? To recap, is that done in DMM diode check mode with the power caps discharged or does one leg need to be pulled?

    Would not look forward to multiple diode testing in that manner with this type of board. Had that bad experience before changing relays on a speaker protect board with those through hole sleeves.
    These are the TL431 part numbers:
    595-TL431AILP
    512-TL431CLP
    863-TL431ACLPRAG

    These are the Zener part numbers:
    78-BZX55B30-TAP

  9. #19
    Forum Veteran 62vauxhall's Avatar
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    No such things as bad days, just bad moments
    Once again, thanks y'all.

    Finally spotted where those resistor's wattage is identified. Must split the order between Mouser & Digikey as Mouser does not have one of those MJE devices so getting both from Digikey.

  10. #20
    Forum Veteran 62vauxhall's Avatar
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    No such things as bad days, just bad moments
    Quote Originally Posted by Gepetto View Post
    These are the TL431 part numbers:
    595-TL431AILP
    512-TL431CLP
    863-TL431ACLPRAG

    These are the Zener part numbers:
    78-BZX55B30-TAP
    Parts are coming. Ordered most of what I will or may need from Mouser except the MJE's which Digikey still have.

    Those different TL431 suffixes....they refer to packaging? I wound up requesting the one ending PRAG.

    BTW Joe, those bright white LED's look lovely behind the 400's tinted lenses. Still seems odd PL used meter lenses that dark with the amount of illumination the original incandescent bulbs produced. It was hard to tell that the amp was even on in a lit room without looking inside directly at the bulbs. With room light off, a pale glow and not enough to read the scale from more than a foot or two away.

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