[Heathkit] SB 1000

Mon, 23 Feb 2004 21:12:56 -0700

Something isn't right about the plates being red at 200 ma...How much power
output are you measuring at the 600 watt input... Sounds like it's probably
a lot less than the 400 or so watts it should be...Do any of the tank
components , including the plate resistor/coil network , look overheated, or
maybe even burnt..?
Sounds like an output coupling problem and the tank is not properly
loaded...Does this occur on all bands..?   73 de Jordan....

Fern Rivard wrote:

> Assuming that the tubes are ok, I would suspect that there is a serious
> problem with the plate current metering like possibly a bad shunt or ?
> Fern
>
> ----- Original Message -----
> From: "Mark S Graalman" <[email protected]>
> To: <[email protected]>
> Cc: <[email protected]>
> Sent: Monday, February 23, 2004 2:50 PM
> Subject: Re: [Heathkit] SB 1000
>
> >   150 ma grid current for a single 3-500Z at 200 ma
> > plate current sounds high to me, I wonder if your
> > grid meter and / or plate meter is lying, or maybe
> > you're loading too heavy. Does the same thing
> > occur on all bands?
> >  What's the value of the primary fuses? Is it
> > wired for 120 or 240? I guess the point I'm wondering
> > about is assuming you aren't loaded too heavy or have a problem
> > in the output network is at 200 ma plate current the amp is
> > at roughly 600 watts input. Add in 75 watts for the filament,
> > another 15% or so for losses I would think the primary
> > current on 220 would be about 3.5 to 4 amps and twice
> > that if you're on 110. If the primary fuses are 10 or 20 amp
> > units I can't help but think your meters are lying to you.
> >
> >
> > On Mon, 23 Feb 2004 15:59:05 -0600 Charles W BWW Burkhardt
> > <[email protected]> writes:
> > > I should have made myself clearer. The normal operating current for
> > > this 3-500z is about 400 ma in CW service. If I get anywhere near
> > > this plate current-even 200 ma- I blow both fuses. The plates become
> > > orange at 200 ma. and I've learned when to stop. The grid current
> > > stays about normal, say 150 ma. Maybe this will clear things up .
> > > Thanks, Charlie K0GPF
> > >
> >
> >
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