[Boatanchors] OA2 CURRENT

[Sandy]

There is a jumper in the 0A2 that is supposed to be wired to cut off the 
load from the supply once the 0A2 is pulled.  This prevents the full 
unregulated voltage from being applied to the regulated B+ line when the 
tube is pulled.  You might check into the regulated B+ line and see if there 
is something drawing current downstream.

73,

Sandy W5TVW
----- Original Message ----- 
From: "Magoo" <magoo at isp.ca>
To: <boatanchors at mailman.qth.net>
Sent: Sunday, August 09, 2009 12:15 PM
Subject: [Boatanchors] OA2 CURRENT


> I'm trying to troubleshoot what appears to be excessive current draw in a
> P/S employing a pair of OA2s.  With all tubes out of the chassis,
> approzimately 10ma is being drawn through the choke (in the ground lead) 
> by
> the bias supply.  When both OA2s are plugged in (with no other tubes
> installed)  that current rises to about 90ma, and that seems excessive to
> me.  Both tubes test OK.....but are they?
>
> B+ at source is 315 and each tube is fed through 4K; with no load I
> calculate 7 ma for the idling current on each tube.  Is my logic flawed, 
> or
> am I dealing with a pair of tubes which test good but are actually bad?
>
> Bill VE3NH
>
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