Help installing progressive standby switch for Blues Junior

Discussion in 'Shock Brother's DIY Amps' started by AspiringGilmour, Jan 30, 2016.

  1. AspiringGilmour

    AspiringGilmour TDPRI Member

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    Today I ordered a Carling progressive 3 way on-standby-off switch for my Blues Jr III. I got it from Antique Electronics and it seemed like a pretty cool mod for only a few bucks.
    Does anyone know how to install it? What wires hook up where? I know basic safety stuff (hand in pocket, discharging caps, etc.) I just don't know how to wire it.
    Any help or instructions would be much appreciated!
     
  2. FenderLover

    FenderLover Poster Extraordinaire

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  3. AspiringGilmour

    AspiringGilmour TDPRI Member

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    Hmmm... I think that I am correct about the on-stdby-off. This is the switch I'm talking about:
    https://www.tubesandmore.com/products/P-H520
    https://d1sjrnpi226dnf.cloudfront.net/spree/attached_files/p-dpst-3way.pdf?1382030369

    And how would I use that schematic?
    Thanks again.
     
  4. FenderLover

    FenderLover Poster Extraordinaire

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    I see, you have the DPST, and it's a special purpose switch. My post works for the common DPDT switch.

    You would normally connect the two leads going to your current power switch go to terminals B and D; the two leads going to you current Standby switch go to A and C.

    However, you don't currently have a Standby on the BJ III so you have to break into the circuit. Without a schematic, it's more tricky deciding where to break into the B+ side. The Mains connection may also need modification to use that switch if both the Hot and Neutral are switched, like on the Blues Jr.

    This one will require pictures and a schematic to perform over the internet. Probably not advisable unless someone has documented it already, which is possible.
     
  5. Wyatt

    Wyatt Tele-Afflicted

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    Low cost but HIGH hassle for minimal payoff.

    The wires aren't there yet.

    As FenderLover notes, the power supply is all PCB based. You'll have to mod the PCB...cut a trace, drill, etc. to be able to split the DC voltage between the diodes (D1-4) and the first filter cap (C25) and run flying leads to the switch. Since the traces are on the bottom of the PCB, it means removing it to work.

    And before someone mentions another way to wire in a Standby switch the BJ3 PT does not have a center tap on it's high-voltage secondary.

    FenderLover is also right that Fender has to switch both Hot and Neutral on the power switch in order to get CE approval. That's why the stock switch is Douple-Pole Single-Throw.
     
  6. AspiringGilmour

    AspiringGilmour TDPRI Member

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    Haha all of this is going over my head. I'll just wait until it arrives and then take a close look
     
  7. Wyatt

    Wyatt Tele-Afflicted

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    In short...it's "you can't get there from here."

    It would require invasive modding by a professional who knows how to work on printed circuit boards. It's a pro job that most pros will refuse because of the high cost to no benefit ratio.
     
  8. AspiringGilmour

    AspiringGilmour TDPRI Member

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    The standby switch is offered as a billm mod and most people agree that it drops in pretty quickly and easily.
     
  9. Wyatt

    Wyatt Tele-Afflicted

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    He must be switching the high voltage AC, not the B+.

    Why is there such a demand for Standby on that amp? What's the point?
     
  10. AspiringGilmour

    AspiringGilmour TDPRI Member

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    Yeah I know that on an amp that small standby isn't at all nessecary to tube life. It's just a nice feature to have.
     
  11. jfromel

    jfromel TDPRI Member

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    The easiest way to add a standby switch is with the Carling progressive switch from Antique Electronics. You will need a short lead in addition to the switch. The mod switches the AC before the rectifier, not B+. On a cream board (made in Mexico) amp install the new switch. Put the black lead from the power cord and the black lead from WJ5 on the left side of the switch. Put the white lead from the power cord on P9 and the white lead from the power transformer on P10. Take the lead that is currently at CP11 and move that to the right side of the switch and take the new lead from the remaining terminal on the switch and connect it to CP11.

    What you have done is hardwired neutral, hot AC from the wall is switched before the fuse and the high power ac is switched before the rectifier. The heaters on the tubes and the LED will get power when the amp is in "Standby". I usually like to fuse hot and switch neutral but the way the amp is designed it would require some soldering.

    Hope this helps.
     
  12. AspiringGilmour

    AspiringGilmour TDPRI Member

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    THANK YOU! I really appreciate the help since there's no guide or instructions anywhere online. I'll try this out this weekend when I have some free time and tell you how it goes. One quick question: do I need any special lead since it's high voltage? Can I just use some regular stranded AWG 22?
    By the way, I bought the amp used and the previous owner had installed your Supreme Mod Kit which I'm very happy with.
     
  13. AspiringGilmour

    AspiringGilmour TDPRI Member

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    By the way, I installed the switch on Saturday and it works great! Thanks again!
     
  14. jonmichael02302

    jonmichael02302 TDPRI Member

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    Mr. Fromel, thank you for sharing how to install this standby switch. After buying the switch, & countless hours of research on how to install it, I noticed you sold out of these standby kits on eBay that included a 330R 5w resistor.... Do I need this resistor? I wish you had these kits before I bought this one on AE cause I'd have much rather bought the kit & saved all this time & headache. WHAT A PAIN this has been! Trust me folks, if you're wanting this mod do yourself a huge favor, WAIT & BUY THE KIT!
     
  15. Wally

    Wally Telefied Ad Free Member

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  16. Willsat

    Willsat NEW MEMBER!

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    Hi,

    I have installed a new power transformer along with the Carling 3 position switch and I am still unsure about the connections, because I have a black lead from the transformer that is not connected to anything. I have one red lead from the transformer going to P11 on the cream board, and the other red lead from the transformer is going to the right side of the switch (the bottom prong). I have the new lead going from the right side of the switch (top prong) to P12 on the cream board. Where should the black lead from the transformer go?

    Thanks.
     
  17. guitarzan13

    guitarzan13 Friend of Leo's

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    How might one do this with a USA version? Nothing matches your numbers Thanks in advance
     
    Last edited: Dec 28, 2016
  18. MilwMark

    MilwMark Doctor of Teleocity Ad Free Member

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  19. guitarzan13

    guitarzan13 Friend of Leo's

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    Thanks... I read that. A friend wants this done. He had this done to his Pro Junior in 1992 and has had NO issues whatsoever.
     
  20. jfromel

    jfromel TDPRI Member

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    White is joined at CP9 and CP4, Red lead from switch to CP12.
     
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