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1983 Concert - bad filter caps?

Discussion in 'Amp Tech Center' started by Little Ricky, Aug 27, 2016.

  1. Little Ricky

    Little Ricky Tele-Holic Silver Supporter

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    Just picked up this amp today.
    Needs a new reverb pot and knob, and a new power switch.

    Anyway, it sounds good, but I'm pretty sure these filter caps are leaking in a major way.
     
  2. Sea Devil

    Sea Devil Friend of Leo's

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    Looks that way. Why is one installed with the poles in the opposite direction from the rest?
     
  3. Darkness

    Darkness Tele-Afflicted

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    Wait for the transformer toast club to chime in. They'll say they're fine and just need 'reforming'.
     
  4. BobbyZ

    BobbyZ Doctor of Teleocity

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    I'd already be ordering a full set of electrolytics for that amp. No matter how good or bad they look.
     
  5. Pup Tentacle

    Pup Tentacle Tele-Holic

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    Sea Devil the first two caps are in series, 2x 285v caps in series @ 220uf yields 570v @ 110uf.
     
  6. Wally

    Wally Telefied Ad Free Member

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    I am not convinced that the amber material there is leaking dialectric. Note that some of that same material can be seen on the aluminum cap covering...away from the end...indicating that the material is a sealant of some sort applied at the factory. That material is found on both ends.
    Ime, there is a spot on the positive end of electrolytics that's is designed to bulge whe the filter cap's dialectic starts to 'leak'. Those bulges will then erupt..sometimes violently and explosively but sometimes slowly. These bulges are not near the lead connection but rather somewhere to the side of the center.
    I could be wrong....but these caps show no physical signs that alarm me. And...ya'll know that I am all in favor of replacing electrolytics. In this amp, I would base my decision on the Sonic's of the amp....which I would have heard before I saw the caps.

    http://www.bing.com/images/search?q...&thid=OIP.M87e60077cca16bc386a57f0b0f724d67o0
     
  7. ranjam

    ranjam Tele-Holic

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    I use more test equipment than God, so out would come my capacitance meter, ESR meter, and even a leakage tester if you can swing it. Yes, it's a waste of time, but for your own amplifier, you aren't running a meter like a taxi.
     
    Last edited: Aug 29, 2016
  8. JD0x0

    JD0x0 Poster Extraordinaire

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    This. Dont care what they look like. The amp is old enough to get new ones.
     
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  9. BobbyZ

    BobbyZ Doctor of Teleocity

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    I'm basing my "replace them all" on the general decline in the quality of electrolytics starting somewhere in the late 60s early 70s.
    Not sure what changed in them but something did. If other electric equipment is any indication. My brother in the heating and air conditioning biz carries a pretty large inventory of them in his service vans and replaces them all the time. The one on my AC unit wasn't ten years old when it went out for instance.
    So I don't waste too much time looking at them and whatever once they pass 20 years.
     
  10. trev333

    trev333 Telefied Ad Free Member

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    here's what my leaky caps looked like... from a 210..

    changing them gave me a lot more volume off the bottom.... my old home setting was @V6... new caps is at @V2....a big difference..

    Leaky Caps1.JPG
     
  11. Little Ricky

    Little Ricky Tele-Holic Silver Supporter

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    Yes, it sounds fine, and my first impression upon seeing the caps was that ALL of them could not have leaked so much, so consistently - so they must be fine. So I posted the pics to see if this was a 'thing' with caps of this vintage, or if I was walking an exploding cap tightrope!
    I think Wally is correct that this is an intentional factory-applied sealant of some kind. Anyone want to post pics of their Rivera amps with stock caps to compare?

    Although I had a Princeton II in the past and liked it with a Sheraton, I found it a little too stiff, and sold it. I've also owned a Champ II, also too stiff for me.
    My main purpose in buying this one was to flip it (and also to see if I would come to love the Rivera-era amps...unfortunately, still no love).

    This one has a bad AC switch and a reverb pot with a broken shaft and missing knob, so I'm going to replace those and pass this on to someone who will love it.
    If I was keeping it, I would be of the preventative re-cap mindset, but since I'm selling it, there's a chance the buyer might appreciate the original components.
     
  12. BobbyZ

    BobbyZ Doctor of Teleocity

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    Probably the way to go for a flip. Seems like you get the same money for one that's been gone through as you do for one that hasn't.
    Then there's guys like me who want them gone through but would rather do it ourselfs.
     
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  13. jefcon1

    jefcon1 Tele-Meister

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    Here is my 83 twin reverb II
    1473268436096.jpg

    Just realized you can't see anything from this pic. Sorry, I just happened to have it on my phone when I read this thread.
     
    Last edited: Sep 7, 2016
  14. Silverface

    Silverface Poster Extraordinaire Platinum Supporter

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    I almost always agree with Wally, but although the appearance doesn't absolutely indicate they're blown they're original from what I can see of one date code - which means they're 33 years old. I would have replaced them twice by now!

    IMO they should be replaced immediately.

    jefcon1 - why were all the tone and bypass caps replaced with orange drops? If a tech did that he was just taking somebody's money - total;y unnecessary. Those get replaced if they're either lousy caps or leaking - but an amp full of nothing but orange drops isn't usually tonal heaven.
     
  15. jefcon1

    jefcon1 Tele-Meister

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    I had no idea they weren't original. I got the amp used in 1990.
     
  16. Lynxtrap

    Lynxtrap Tele-Holic

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    I think the orange drops are stock in these amps.
     
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  17. flyswatter

    flyswatter Friend of Leo's

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    They look original. My 1980 or 81 Super Reverb has orange drops that look exactly the same.
     
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  18. Wally

    Wally Telefied Ad Free Member

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    The Orange Drops are original to that amp that jet on shows us, ime. And...there are more than one type of OD. Some of those look like they are the 716 series...some may be 715's.
     
  19. Little Ricky

    Little Ricky Tele-Holic Silver Supporter

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    D076FA5F-65A9-4766-8049-F751C9D7C12C.jpeg 052AF664-9968-4B24-98AC-A35BEC085140.jpeg So soon after buying this amp I replaced the Reverb knob and power switch.
    The amp sounded fine, but it was really just taking up space and not getting played.
    I recently found a buyer and recommended that the caps be replaced. He agreed and was patient enough to wait for me to do the job.
    I also replaced the speaker with one from a HRDlx. The original was distorting on lower bass notes.

    So here she is, ready to rock for another couple decades!
     
    Last edited: Aug 30, 2019
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