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    Auto Bias Board Wiring Question

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    breading

    Posts : 28
    Join date : 2010-01-08

    Auto Bias Board Wiring Question Empty Auto Bias Board Wiring Question

    Post by breading on Tue Dec 18, 2018 3:06 pm

    I am installing the Auto Bias board into my VTA ST70 and would like to keep the front octal socket bias testing pins active.

    They currently run from pins 4 and 8, respectively, on the front sockets to pin 1 on the output tubes. Now that the 10 ohm resister has been removed from the output socket, what is the new connection point to allow bias checking from the front sockets?

    On the AB board? If so, where. If not, what is the best connection point.

    Thanks for the help.
    tubes4hifi
    tubes4hifi
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    Join date : 2008-11-30

    Auto Bias Board Wiring Question Empty Re: Auto Bias Board Wiring Question

    Post by tubes4hifi on Tue Dec 18, 2018 6:36 pm

    same place, you don't have to change any wiring, those wires are still connected to the 10 ohm resistors on the AB board now
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    breading

    Posts : 28
    Join date : 2010-01-08

    Auto Bias Board Wiring Question Empty Re: Auto Bias Board Wiring Question

    Post by breading on Thu Dec 27, 2018 2:20 pm

    Roy,

    Earlier you had responded to my question regarding retaining the bias test points on the 4 and 8 pins of the front octal sockets on my ST-70 as I installed the AB board. You said the points should still be operational after installation of the AB board.

    I have completed the install and all appears to be in working order except I get no reading on the 4 and 8 pins.

    I am curious as to why this is the case. I did install the fuse/MOV setup as described by Aquaazul in his July 15, 2018 post #193. Could this be the reason?

    If so, is there a work around?

    By the way, have you made progress on the SP14 upgrade to full remote as yet?

    Thanks,

    Bruce

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