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    I let the smoke out.

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    bbqjoe
    bbqjoe

    Posts : 101
    Join date : 2018-12-03

    Re: I let the smoke out.

    Post by bbqjoe on Tue Jan 01, 2019 5:47 pm

    audiobill wrote:You don't need insulation on legs....
    Unless you live in Minnasoda! Oofda! tongue
    Bob Latino
    Bob Latino
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    Location : Massachusetts

    Re: I let the smoke out.

    Post by Bob Latino on Tue Jan 01, 2019 6:32 pm

    I discussed this with Roy a couple of days ago .. If you set the Russian K42-Y PIO caps as below (first photo) you don't really need the shrink tubing around the two leads. Set UP like this, the caps will be about 1/4 of an inch above the board and the leads should not be able to touch anything on the board. Now - Considering that the inner lead does have about 275 VDC and the outer lead about -40 to -50 VDC what I am going to do is include shrink tubing on all future Russian PIO caps as seen in the SECOND photo. The second photo shows the installation of the two leads with the black shrink tubing. After the cap is installed you can use a hair dryer to shrink the tubing around the lead.

    Bob





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    audiobill

    Posts : 382
    Join date : 2014-03-13
    Location : Philadelphia

    Re: I let the smoke out.

    Post by audiobill on Wed Jan 02, 2019 8:26 am

    With the insulation, be sure to solder carefully so there is good contact to the board. I like to sand the leads a little before soldering to be sure there is.
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    New2Tubez

    Posts : 35
    Join date : 2018-03-20
    Location : NY

    Re: I let the smoke out.

    Post by New2Tubez on Wed Jan 02, 2019 4:13 pm

    When I'm more clear on the AB board, I'll replace my K-40Y's with the longer, thinner K-42Y's.
    I put clear heat shrink on the 42's so the values could still be read. I'll heat shrink the leads when I do the install.


    billinrio
    billinrio

    Posts : 92
    Join date : 2018-01-03

    Re: I let the smoke out.

    Post by billinrio on Thu Jan 17, 2019 12:18 pm

    bbqjoe wrote:

    Anyways, here's where my problem was.
    I broke the wire going to the switch while tying everything up.
    It arced between the switch and the resistor.
    Resistor was fried, not to mention the switch.




    The place in your initial post where you say you replaced the original switch with a toggle switch did raise a red flag for me.
    bbqjoe
    bbqjoe

    Posts : 101
    Join date : 2018-12-03

    Re: I let the smoke out.

    Post by bbqjoe on Thu Jan 17, 2019 4:34 pm

    billinrio wrote:
    The place in your initial post where you say you replaced the original switch with a toggle switch did raise a red flag for me.
    It's just as simple as a switch can be.

    I found the slider switch could be slid, and not make proper contact consistently. Toggles just don't behave like that.
    pichacker
    pichacker

    Posts : 77
    Join date : 2016-08-01
    Age : 54
    Location : Near to London - UK

    Re: I let the smoke out.

    Post by pichacker on Fri Jan 18, 2019 4:28 am

    The other thing to consider with the triode/pentode switches are the peak voltages present on them under running conditions. Differential between the two halves you could have almost 2xHT voltage. A good quality switch should be used here.
    bbqjoe
    bbqjoe

    Posts : 101
    Join date : 2018-12-03

    Re: I let the smoke out.

    Post by bbqjoe on Fri Jan 18, 2019 10:40 am

    pichacker wrote:The other thing to consider with the triode/pentode switches are the peak voltages present on them under running conditions. Differential between the two halves you could have almost 2xHT voltage. A good quality switch should be used here.

    The switches used for triode/pentode switching are the ones Bob provides with the kit.
    deepee99
    deepee99

    Posts : 2076
    Join date : 2012-05-23
    Location : Wallace, Idaho

    Re: I let the smoke out.

    Post by deepee99 on Fri Jan 18, 2019 12:07 pm

    bbqjoe wrote:
    pichacker wrote:The other thing to consider with the triode/pentode switches are the peak voltages present on them under running conditions. Differential between the two halves you could have almost 2xHT voltage. A good quality switch should be used here.

    The switches used for  triode/pentode switching are the ones Bob provides with the kit.
    Those switches, beefy as they are, should only be toggled with the amp(s) off or no signal input to avoid Pichacker's scenario.
    bbqjoe
    bbqjoe

    Posts : 101
    Join date : 2018-12-03

    Re: I let the smoke out.

    Post by bbqjoe on Fri Jan 18, 2019 12:18 pm

    deepee99 wrote:
    bbqjoe wrote:
    pichacker wrote:The other thing to consider with the triode/pentode switches are the peak voltages present on them under running conditions. Differential between the two halves you could have almost 2xHT voltage. A good quality switch should be used here.

    The switches used for  triode/pentode switching are the ones Bob provides with the kit.
    Those switches, beefy as they are, should only be toggled with the amp(s) off or no signal input to avoid Pichacker's scenario.

    I wouldn't go so far as to call them beefy, seeing as they probably fall into the micro switch category.
    So far, I'm not in the habit of switching back and forth.
    Bob states it's OK to switch as long as the amp isn't cranked up.

    Since he is the kit designer, I have faith in him that he didn't cut corners and use something outside of tolerances, but I certainly could see using a chunkier switch where as much as 500 volts is concerned.
    bbqjoe
    bbqjoe

    Posts : 101
    Join date : 2018-12-03

    Re: I let the smoke out.

    Post by bbqjoe on Wed Feb 20, 2019 10:20 pm

    I don't think I'll ever get over this, I'm permanently scarred.
    The shorting happened right after the click of the relay on the time delay board.

    Ever since the accident and repair, everything has been fine.

    But every time I turn the amp on, I wait for the click, and cringe in fear of snap crackle pop!

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