Amplifone HV

From: Joseph J. Welser <jwelser_at_crystal.cirrus.com>
Date: Fri Aug 29 1997 - 12:24:00 EDT

Fellow vector posse,

        I just swapped an Amplifone back into my Quantum, and have made the
determination that my HV transformer is bad (surprise, surprise.)

        The only reason why I post this is because of all the mention of
the BLACK HV transformers being indestructable, and this is the kind we're
talking about here....

        I have good +-24V. I measured the following voltages (rounded) on the
BU406D (which I tested, and it looks good) B: -24V, E: -24V, C: +24V

        Now, having a Vbe of ~0 surprised me at first, but it seems that the
BU406D has an internal resistor between the Base and Emitter. The other thing
that sounds off warning bells is the 48V Vce. The BU406D was cool to the
touch, and with 48V across that CE junction, I figured it should be at least
warm (if there was any current flowing through it.)

        I'm getting a B+ of like 22V or 23V (I'm sure it's 24V minus the diode
drop of CR3)

        So whaddaya think? I've read Gregg's FAQ, and there isn't much about
the Amplifone in there....

Thanks,

Joe

BTW: If I didn't mention it explicitly, I'm not getting any high voltage. I
don't hear a high-pitched tone, or a crackle, or anything from the HV unit.
Received on Fri Aug 29 09:21:44 1997

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