[Boatanchors] 5+ megohms primary?

[GBrown]

I would say that the 5 megs your getting is thru the parallel lamp filament.
I don't have a diagram but remove the lamp and measure it again.
    Al has the rite idea, you cant get it to dry. Take your time and make
sure everything is dry as can be. An arced path could also be a source for a
high resistance ground.
Take care and GOOD LUCK,
Gary...WZ1M
----- Original Message -----
From: "Al Parker" <anchor at ec.rr.com>
To: <StephenTetorka at cs.com>; <boatanchors at mailman.qth.net>
Sent: Thursday, November 11, 2004 5:02 PM
Subject: Re: [Boatanchors] 5+ megohms primary?


> Hi Steve,
>     Do as Doug says to further check it out, but I'm not crazy abt that
> 15meg with just a lo-voltage ohmmeter.  If some of that resistance to
> ground was the line bypass caps (hopefully), maybe you're not too bad off.
> Remove them, and put a 60w litebulb under it for a day or 3 to try to dry
> any moisture out, before you put any voltage on it, then re-check.
>     I use an ohmeter to check things for leakage resistance, but also use
> a megger with a variable DC supply, and find much lower resistances when
> the voltage gets up a bit, even at 2-300 volts, and something like a BBOD
> that looked to be 10-15 megs on the ohmmeter is often down around 1 meg at
> 400-600vdc.
>     Go at it very slowly and don't let the smoke out, once  it does,
> you're in for a rewind.
>     Sounds like a nice project, but still not those 2x813's ;-)
> 73,
> Al, W8UT
> New Bern, NC
> BoatAnchors appreciated here
> http://www.thecompendium.net/radio/
> http://www.hammarlund.info
>
>
> ----- Original Message -----
> From: <StephenTetorka at cs.com>
> To: <boatanchors at mailman.qth.net>
> Sent: Thursday, November 11, 2004 11:10 AM
> Subject: [Boatanchors] 5+ megohms primary?
>
>
> > Hi all:
> >
> > I am presently restoring a AM/CW 6 foot rack rig; 2X1625 in the final.
> > Homebrew in 1948 by W2PLY now moving to Senior Residence.
> >
> > I'm starting my checkout with the 95 pound power supply.
> >
> > With no power supplied, when using a VTVM from either primary lead to
> ground of the main power transformer, I get a reading of 15 megohms with
> the SPST in the primary in the OFF position.
> > I get 5 meghoms in the ON position - which completes one primary leg
> circuit allowing the 115 VAC to primary.
> >
> > Naturally, I'd expect infinity on this open circuit.
> >
> > Not much there: terminal screws on the back chassis; hvy AWG to the
> switch, a lamp indicator in parallel on the primary amd the xmfr bolted to
> the chassis.
> >
> > I would guess that some insulation somewhere has 'gone old'.
> >
> > Your generous comments and suggestions most welcomed.
> >
> > Regards,
> > Steve
> > WA2TAK
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> > ** List Administrator - Duane Fischer, W8DBF/W9WZE **
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> >
> >
>
>
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>