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No ears , k2#5315

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r opdebeke

No ears , k2#5315

Hi all,

I'm building K2 #5315, everything went well upto page 64 where I should do
the IF amplifier alignment.
It appears that there is no audio at all ( beter say very very weak ).
I cheked the earphones by hitting the SPOT , which was ok.
But I can not hear the 7000 internal signal at all.

When I tune my VFO there is definitely a signal and the S-meter runs very
well, especially above 7100 where all of those commercial staions are.

Checked the agc . I got 3.78 V on U2 pin 5 , that is fully CCW R1.
AF gain pot is approx 5 k , Rp6 (7-8 ) is 5K , R1 is 50K

checked 8R , D6 is 7.73 V and D7 is 0 V

All looks ok , anyone any suggestion ?

Cheers
Roger
OE6MSF

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Don Wilhelm-3

RE: No ears , k2#5315

Roger,

If the S-meter is lively, most likely the stages through the IF amplifier
are probably good. Be certain you see an increase in the S-meter when the
Pre-Amp is turned on and a decrease when the Attenuator is turned on -
expect about a 1 or 2 LED bar difference in both cases. Your voltage at the
AGC Threshold of 3.78 volts is not an indicator of a problem at this point.

Did you pre-set the BFO frequencies to the values shown on page 89? If not,
that alone may be your problem.

If you have set the BFOs and still have inadequate audio, the problem can be
in the 2nd Xtal Filter, or the Product Detector, or the Mute or AF Amp
stages. Check the DC voltages for these stages and compare to the DC
voltage chart in Appendix F as a first step - you should measure DC Voltages
within 10% of the value shown in the chart.

If the DC Voltages are OK, check all the signal paths from the 2nd Xtal
Filter through the AF Amp for good solder connections - the signal paths
include all 3 boards and their connectors because the AF Gain control is
located on the Front Panel. Use the schematic as a guide in identifying the
signal paths.

The sidetone is injected into the audio amp IC at a separate pin from the
audio, so that indicates only that the Audio IC is capable of producing some
sound.

73,
Don W3FPR

> -----Original Message-----
>
> I'm building K2 #5315, everything went well upto page 64 where I
> should do
> the IF amplifier alignment.
> It appears that there is no audio at all ( beter say very very weak ).
> I cheked the earphones by hitting the SPOT , which was ok.
> But I can not hear the 7000 internal signal at all.
>
> When I tune my VFO there is definitely a signal and the S-meter
> runs very
> well, especially above 7100 where all of those commercial staions are.
>
> Checked the agc . I got 3.78 V on U2 pin 5 , that is fully CCW R1.
> AF gain pot is approx 5 k , Rp6 (7-8 ) is 5K , R1 is 50K
>
> checked 8R , D6 is 7.73 V and D7 is 0 V
>
> All looks ok , anyone any suggestion ?
>
> Cheers
> Roger
> OE6MSF
>
>

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Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
http://mailman.qth.net/mailman/listinfo/elecraft

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

r opdebeke

RE: No ears , k2#5315

Bad connection on X6 was the problem ,
Thanks all who helped tackle me this problem, now I can listen for some 40
meter actrivity !!!

Roger
OE6MSF

>From: "Don Wilhelm" <[hidden email]>
>Reply-To: <[hidden email]>
>To: "r opdebeke" <[hidden email]>,<[hidden email]>
>Subject: RE: [Elecraft] No ears , k2#5315
>Date: Tue, 14 Feb 2006 08:01:33 -0500
>
>Roger,
>
>If the S-meter is lively, most likely the stages through the IF amplifier
>are probably good. Be certain you see an increase in the S-meter when the
>Pre-Amp is turned on and a decrease when the Attenuator is turned on -
>expect about a 1 or 2 LED bar difference in both cases. Your voltage at
>the
>AGC Threshold of 3.78 volts is not an indicator of a problem at this point.
>
>Did you pre-set the BFO frequencies to the values shown on page 89? If
>not,
>that alone may be your problem.
>
>If you have set the BFOs and still have inadequate audio, the problem can
>be
>in the 2nd Xtal Filter, or the Product Detector, or the Mute or AF Amp
>stages. Check the DC voltages for these stages and compare to the DC
>voltage chart in Appendix F as a first step - you should measure DC
>Voltages
>within 10% of the value shown in the chart.
>
>If the DC Voltages are OK, check all the signal paths from the 2nd Xtal
>Filter through the AF Amp for good solder connections - the signal paths
>include all 3 boards and their connectors because the AF Gain control is
>located on the Front Panel. Use the schematic as a guide in identifying
>the
>signal paths.
>
>The sidetone is injected into the audio amp IC at a separate pin from the
>audio, so that indicates only that the Audio IC is capable of producing
>some
>sound.
>
>73,
>Don W3FPR
>
> > -----Original Message-----
> >
> > I'm building K2 #5315, everything went well upto page 64 where I
> > should do
> > the IF amplifier alignment.
> > It appears that there is no audio at all ( beter say very very weak ).
> > I cheked the earphones by hitting the SPOT , which was ok.
> > But I can not hear the 7000 internal signal at all.
> >
> > When I tune my VFO there is definitely a signal and the S-meter
> > runs very
> > well, especially above 7100 where all of those commercial staions are.
> >
> > Checked the agc . I got 3.78 V on U2 pin 5 , that is fully CCW R1.
> > AF gain pot is approx 5 k , Rp6 (7-8 ) is 5K , R1 is 50K
> >
> > checked 8R , D6 is 7.73 V and D7 is 0 V
> >
> > All looks ok , anyone any suggestion ?
> >
> > Cheers
> > Roger
> > OE6MSF
> >
> >
>