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Thread: Ampeg SVT-3 Pro - starts up - then fan cuts out before relay switches - no output.

  1. #1
    Forum Member yankeerob's Avatar
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    Ampeg SVT-3 Pro - starts up - then fan cuts out before relay switches - no output.

    As in the title - the amp switches on, fan starts and then cuts out before the time delay relay is switched... It used to do all that but the fan would stay on - the pre-amp was working fine (into an external power amp) but the power amp was very low output and distorted. I have replaced all the 220Ω/10W and 0.47Ω/5W power resistors (they all looked like they'd seen better days), all the output devices, all the 5600uF/80V and 47uF/450V electrolytics and a handful of the Wima coupling caps that were near any appreciable source of heat.

    When I first powered the amp on - the fan ran - the relay switched I plugged a cable in and put a little gain and master vol on and tapped the tip of the cable to see if anything was happening and it sounded pretty healthy. I went to grab a bass and the fan stopped running and there was no output. I have cycled it 4-5 times and now it does what I've described in the title.

    Any thoughts??

    Many thanks!!

    Rob
    If I could find a road to get away it wouldn't be too soon....... Shipwreck Moon.......

  2. #2
    Forum Member yankeerob's Avatar
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    Re: Ampeg SVT-3 Pro - starts up - then fan cuts out before relay switches - no output

    For the sake of information -

    All of the above were the correct actions to take... provided of course you get your output devices from a reliable source... i couldn't imagine SLM paying too much attention to that and thus felt pretty safe getting them from a source with a no qualms return policy.

    Turns out that a common problem with these is the fan...

    I'm not absolutely sure yet but am stumping up the required $50 to acquire the exact Comair Rotron ST24A3 to ensure the exact airflow and more importantly - current draw - is adhered to.

    Freakin' SLM... did they make anything worth writing about????

    Best wishes to all at TFF...

    yer bud...

    YR
    If I could find a road to get away it wouldn't be too soon....... Shipwreck Moon.......

  3. #3
    Forum Member CoyotesGator's Avatar
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    Re: Ampeg SVT-3 Pro - starts up - then fan cuts out before relay switches - no output

    Do you have a good clear schematic you could post or link to?
    What happend?
    Who let the magic smoke out?

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