[Elecraft] Fwd: AW: K3 KPA3 bias adjust

[Mike Harris]

Hi,

Forwarded a 2009 email exchange for your info. I have NOT tried this so 
use with care and at your own risk.

Regards,

Mike VP8NO


-------- Forwarded Message --------
Subject: AW: [Elecraft] K3 KPA3 bias adjust
Date: Sat, 3 Jan 2009 19:46:55 +0100
From: Koppendorfer Klaus <KK at ccf.net>
To: Jan Erik Holm <sm2ekm at telia.com>
CC: Elecraft at mailman.qth.net <Elecraft at mailman.qth.net>

Locate the BIAS pot at the front of the KPA3, between the heat sink and 
the KPA3 shield. Note what the display current is in the VFO B readout 
when you tap the Display button and turn the VFO B knob to the current 
readout. In RX, it should be 1.0A or so.   In XMIT (not TUNE), it should 
be about 1.90 to 2.0A when the Power knob is set to 12w or above so the 
KPA3 is made active (but there is no RF output since XMIT is used). Or 
you can press the PTT button but do not speak.

If there is much more current than this, set the BIAS pot to minimum 
(fully counter clockwise). Then tap XMIT (not TUNE) and note what the 
current is in VFO B's readout. Slowly turn up the BIAS pot until you see 
400-500mA more current that was seen with the BIAS pot at minimum.

73
OE6KYG
KX1 244
K2 1331
K3 115


> -----Ursprüngliche Nachricht-----
> Von: elecraft-bounces at mailman.qth.net [mailto:elecraft-
> bounces at mailman.qth.net] Im Auftrag von Jan Erik Holm
> Gesendet: Samstag, 03. Jänner 2009 19:35
> Cc: Elecraft at mailman.qth.net
> Betreff: Re: [Elecraft] K3 KPA3 bias adjust
>
> Thanks Ron but I knew this already.
>
> Probably have to write to K3support and ask,
> however I´m very surprised nobody could answer
> on the reflector.
>
> Jim SM2EKM
> ----------------------
> Ron D'Eau Claire wrote:
> > Hello Jim:
> >
> > That pot, along with all the other trimmers in the K3, is adjusted at
> the
> > factory. There are specific cautions against touching any of them in the
> > field; all field adjustments are done in firmware.
> >
> > If you have a problem with the KPA3, suggest you post a message to
> > K3support at elecraft.com. If an adjustment is needed that can be done in
> the
> > field, one of the fellows there can give you specifics.
> >
> > Ron AC7AC
> >
> >
> >
> > -----Original Message-----
> > From: elecraft-bounces at mailman.qth.net
> > [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Jan Erik Holm
> > Sent: Saturday, January 03, 2009 6:55 AM
> > To: Elecraft at mailman.qth.net
> > Subject: [Elecraft] K3 KPA3 bias adjust
> >
> > I find nothing about it in any manual. R11 on KPA3
> > I guess. What are the specifications for the bias
> > adjust?
> >
> > 73 Jim SM2EKM