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    ST120 Test Voltages

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    sKiZo

    Posts : 1310
    Join date : 2013-04-01
    Location : Michigan USA

    ST120 Test Voltages

    Post by sKiZo on Mon Oct 07, 2013 12:22 pm

    I remember seeing somewhere a list of readings for various points on the board. Of course, I bookmarked it, and of course, lost the bookmark ...

    Anyone? Seems like that would be a nice sticky ...



    Bob Latino
    Admin

    Posts : 2413
    Join date : 2008-11-26
    Location : Massachusetts

    Re: ST120 Test Voltages

    Post by Bob Latino on Mon Oct 07, 2013 1:08 pm

    Look on the schematic in you assembly manual .. There are some voltages on the schematic included in your assembly manual .. Note - those voltages are + or - 10%

    Bob

    sKiZo

    Posts : 1310
    Join date : 2013-04-01
    Location : Michigan USA

    Re: ST120 Test Voltages

    Post by sKiZo on Mon Oct 07, 2013 3:55 pm

    OK then ... I do remember seeing a checklist though, so if anyone runs across it ... thanx in advance.

    FINALLY got around to slipping some juice to the amp ... no explosions, the fire extinguisher remains parked, and good heaters on the drivers. Joy.

    Note ... I'm supposed to be seeing 6.1 - 6.5 at the driver board, but it's a steady 7.1 here. Sounds reasonable as I'm seeing almost 124vac out of the wall today. Definitely gonna have to consider running the amp full time off a variac ...

    Bob Latino
    Admin

    Posts : 2413
    Join date : 2008-11-26
    Location : Massachusetts

    Re: ST120 Test Voltages

    Post by Bob Latino on Mon Oct 07, 2013 4:29 pm

    sKiZo wrote:OK then ... I do remember seeing a checklist though, so if anyone runs across it ... thanx in advance.

    FINALLY got around to slipping some juice to the amp ... no explosions, the fire extinguisher remains parked, and good heaters on the drivers. Joy.

    Note ... I'm supposed to be seeing 6.1 - 6.5 at the driver board, but it's a steady 7.1 here. Sounds reasonable as I'm seeing almost 124vac out of the wall today. Definitely gonna have to consider running the amp full time off a variac ...
    The check list that you mention is also in the VTA ST-120 assembly manual.

    With 124 VAC off the mains, all your voltages will be higher than normal. If you don't use a variac (set to about 118 VAC) then you will probably have shorter than normal tube life in your amp.

    Bob

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