RT3000p plate amp repairs?

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ChrisD06
ChrisD06 Posts: 901
I have the schematics, I have the list of capacitors and tools needed, now I just need to know: any advice?

Any common failures I should know of, any list of symptoms to rule out certain problems? Is it even worth $250 CAD to repair them myself or should I spend the extra $400 and just buy new amps?

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  • txcoastal1
    txcoastal1 Posts: 13,145
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    If you have the skills and time to choose your parts and repair yourself, then I would do that. At least you know what was done. If you buy used/repaired, and don't know the seller then that's rolling the dice IMHO

    I've attached a couple links from the forum

    https://forum.polkaudio.com/discussion/159800/plate-amp-repairs-for-vintage-speakers

    https://forum.polkaudio.com/discussion/157496/rt3000p-plate-amps-failure
    2-channel: Modwright KWI-200 Integrated, Dynaudio C1-II Signatures
    Desktop rig: LSi7, Polk 110sub, Dayens Ampino amp, W4S DAC/pre, Sonos, JRiver
    Gear on standby: Melody 101 tube pre, Unison Research Simply Italy Integrated
    Gone to new homes: (Matt Polk's)Threshold Stasis SA12e monoblocks, Pass XA30.5 amp, Usher MD2 speakers, Dynaudio C4 platinum speakers, Modwright LS100 (voltz), Simaudio 780D DAC

    erat interfectorem cesar et **** dictatorem dicere a
  • ChrisD06
    ChrisD06 Posts: 901
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    @txcoastal1 after reading through those posts, it seems like the capacitors are probably my issue.

    One amp board actually worked but I took it out anyways, threw it back in, and voila, it's silent. No humming. Took one look at the factory solder joints and wow oh wow are they absolutely terrible. Probably just gonna reflow and recap and see where it gets me.
  • F1nut
    F1nut Posts: 49,993
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    The solder work couldn't be that bad, they've lasted 25 years. I also doubt Polk made the plate amps.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."


    President of Club Polk

  • ChrisD06
    ChrisD06 Posts: 901
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    @F1nut
    d9oncb0kyauj.jpg
    398qhxbuwrw5.jpg

    Looks really bad to me. It works, but it's definitely not what I'd consider quality.
  • ChrisD06
    ChrisD06 Posts: 901
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    mla3559f97rh.png

    This is a bad trace and here's how it was repaired. Absolutely insane this made it past QC
  • F1nut
    F1nut Posts: 49,993
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    Someone has worked on it.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."


    President of Club Polk

  • F1nut
    F1nut Posts: 49,993
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    Since the OP hasn't stated I'd like to know if you bought them new or used?
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."


    President of Club Polk

  • VR3
    VR3 Posts: 28,232
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    Yeah I can assure you that is not oem work
    - Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit.
  • ChrisD06
    ChrisD06 Posts: 901
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    @F1nut @VR3

    I bought these RT3000ps used. The amps in them are the originals and I bought them from the OG (since new) owner. He said they were used for a couple years then put in storage for literally like a decade, which is a miracle the amps in these even lasted me a year. All 3 amp boards I have look like this and have terrible joints. One is in a box which says "Polk Audio Genuine Part" or something along those lines, and the other 2 were in the towers.

    It certainly doesn't look OEM, but considering the unused brand new (from Polk in Baltimore) amp looks the same, I'm inclined to believe these are just crap picks from QC. Either way, I'll fix them up. Will run a jumper wire for that bad trace and will recap and reflow the bad joints. Will leave the good joints alone.
  • F1nut
    F1nut Posts: 49,993
    edited May 2023
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    There's no way in hell those boards came that way from Polk. Sellers lie all the time and the fact they had an extra amp says to me the seller had amp issues a long time ago. Most likely they had one replaced under warranty and blew that one too, so had some hack repair all three.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."


    President of Club Polk

  • ChrisD06
    ChrisD06 Posts: 901
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    @F1nut It's possible. The only thing I don't get is why all of the caps are OEM. They're all the exact same ones used by Polk.

    Though I suppose the issue could have been something other than the caps. Could have been a self repair too...
  • F1nut
    F1nut Posts: 49,993
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    It's easy enough to figure out what's been worked on.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."


    President of Club Polk

  • ChrisD06
    ChrisD06 Posts: 901
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    @F1nut Not in this case. The spare amp was still sealed in box in my case, and the banana plug caps were still in place, yet the solder job is still very bad.

    Either way, they lasted 25 years, I'm sure it's good enough, but I'll try to do it even better.
  • F1nut
    F1nut Posts: 49,993
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    It's obvious just by looking at your pics that components have been replaced, therefore they didn't come from Polk that way, period.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."


    President of Club Polk

  • ChrisD06
    ChrisD06 Posts: 901
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    @F1nut Well now that just makes this DIY repair 8x harder. You think any of those components are going to be bad? Considering lots of these crappy solder joints are on the ICs, which are unobtanium. Maybe I should just sell my RT3000ps at this point
  • F1nut
    F1nut Posts: 49,993
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    It's impossible for me to answer that.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."


    President of Club Polk

  • ChrisD06
    ChrisD06 Posts: 901
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    @F1nut better just try the repair then. Good news is I was wrong about all 3 having bad solder joints, it was just lighting, the new one has amazing solder joints and I'll use that as amp #1, but the other amps are scaring me.
  • ChrisD06
    ChrisD06 Posts: 901
    edited June 2023
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    Reviving an old thread. One of the amps worked fine. Even in working condition, I took it out of the subwoofer, let it sit for around 11 months, powered it back up and it didn't work at all. Repaired the joints on 2 connectors, replaced the filter capacitors, and it does the exact same thing.

    No hum, no click from the relay, no nothing. Any ideas?

    I think I did a pretty good job with those caps though!
    selab5vu929h.jpg
  • txcoastal1
    txcoastal1 Posts: 13,145
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    Need more pics of what looks like a hot mess
    See circled in green
    7a4lcn3ztbm5.jpeg
    2-channel: Modwright KWI-200 Integrated, Dynaudio C1-II Signatures
    Desktop rig: LSi7, Polk 110sub, Dayens Ampino amp, W4S DAC/pre, Sonos, JRiver
    Gear on standby: Melody 101 tube pre, Unison Research Simply Italy Integrated
    Gone to new homes: (Matt Polk's)Threshold Stasis SA12e monoblocks, Pass XA30.5 amp, Usher MD2 speakers, Dynaudio C4 platinum speakers, Modwright LS100 (voltz), Simaudio 780D DAC

    erat interfectorem cesar et **** dictatorem dicere a
  • ChrisD06
    ChrisD06 Posts: 901
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    Okay update:

    The auto position didn't work. I tried what I thought was the on position... turns out that was the off position. I tried the on position this morning AND HOLY SMOKES THEY WORK. AND EVEB BETTER IS THE AUTO POSITION WORKS TOO.

    I think the caps in the preamp board were just so discharged that they couldn't send a signal to the amp board to engage the relay, so when I charged them up it fixed that. I mean wow, just wow. I am thoroughly impressed with myself for somehow managing this feat.

    Time to go for number 2, baby!