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NEW OLD STOCK...Should I worry?

Discussion in 'DIY' started by z-adamson, Jun 26, 2018.

  1. Tim64

    Tim64 Super Member

    Southern Oregon
    Ditto here it chops the ac wave form, a friend of mine way back blew up his receiver using a dimmer control.
    Bill Ferris likes this.


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  2. Scott75s1974

    Scott75s1974 Active Member

    Just a question, not a confident suggestion. A dimmer won't work as a jury rigged variac for the reasons cited. But could one use the secondary from a spare amp/receiver that would provide say 60 or 80 VAC? It wouldn't work for careful dialing up. But could it allow some soaking time to reform capacitors?
  3. z-adamson

    z-adamson Super Member

    Got these preamps in my hands and I have been running them on a 25w bulb for a while now.

    Date of manufacture is a bit older than I thought. They are from 2002.

    Anyhow, bulb stays dim on all of them.

    So, I ran them on the bulb for about 12 hours then wall power for about 12 hours. I took the tops off and looked around inside. Nothing odd. No swollen caps or anything. Heatsink mounted transistors get warm as they should.

    Should I call them good?

    I have not yet run audio through them.
    Bill Ferris likes this.
  4. OMGCat!

    OMGCat! AK Subscriber Subscriber

    El Sereno, CA
    I'd have no concerns about using them after running for that length of time. Sounds like they're ready for a proper test in your system.
  5. petehall347

    petehall347 the brandy coffee man Subscriber

    uk.. the middle bit
    give them a try for sure

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