K2 power control

   Hi,

   I  need  some  help.  I  can  not  adjust  my power anymore when K2 is
   connected   to   the  100  W  PA.  The  PA  is  overloaded  and  power
   meter shows 200 watt !!!

   I tried  to switch off  PA in menu, but in this ca   running with maximum QRP power. 

   I assume something goes wrong with VRFDET.

   If I disconnect th
   How could I investigate to find the reason for this fault ?

   73 de Joerg (DL3QQ)
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[Don Wilhelm-3]

Joerg,

You either have something wrong with the wattmeter in the KPA100 or have
something wrong in the path from the wattmeter forward power circuit to the
VRFDET output from the KPA100.

During a quick keydown period (with only the base K2 powered or with the PA
turned off in the menu), check the following points on the KPA100 (in
order)to determine at which point the voltage disappears - these should all
be DC voltages - you should expect about 4 volts when the base K2 is
developing 10 watts or more:

U5 pin 5
U5 pin 7
U6 pin 3
U6 pin 6

U6 pin 6 is the KKPA100 output signal for the VRFDET line, and if you have
voltage to that point, look for an open in the ribbon cable (pin 10).

73,
Don W3FPR

> -----Original Message-----
>
>    I  need  some  help.  I  can  not  adjust  my power anymore when K2 is
>    connected   to   the  100  W  PA.  The  PA  is  overloaded  and  power
>    meter shows 200 watt !!!
>
>    I tried  to switch off  PA in menu, but in this ca=e it is still
>    running with maximum QRP power. 
>
>    I assume something goes wrong with VRFDET.
>
>    If I disconnect th= PA from K2 power adjustment works fine.
>
>    How could I investigate to find the reason for this fault ?
>
>    73 de Joerg (DL3QQ)
>

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Don,

I checked the voltages during quick keydown.

U5 pin 5     2,5 V
U5 pin 7     2,5 V
U6 pin 3     2,5 V
U6 pin 6     0,06 V    

It looks like U6 is killed. Pin 6 does not show 2,5 V during transmit. I
think I know what was happend ;-)

I soldered a new cable for my KAT100 tuner to extent the length. I
forgot to disconnect the AUX connector from K2 side. Pin 6 of U6 is
connected to pin  7 of the AUX I/O port.

I will replace U6 and test again.


73 de Joerg (DL3QQ)

-----Original Message-----
Date: Sun,  4 Jun 2006 04:30:01 +0200
Subject: RE: [Elecraft] K2 power control
From: "Don Wilhelm"
To: , "Elecraft"

Joerg,

You either have something wrong with the wattmeter in the KPA100 or have
something wrong in the path from the wattmeter forward power circuit to
the
VRFDET output from the KPA100.

During a quick keydown period (with only the base K2 powered or with the
PA
turned off in the menu), check the following points on the KPA100 (in
order)to determine at which point the voltage disappears - these should
all
be DC voltages - you should expect about 4 volts when the base K2 is
developing 10 watts or more:

U5 pin 5
U5 pin 7
U6 pin 3
U6 pin 6

U6 pin 6 is the KKPA100 output signal for the VRFDET line, and if you
have
voltage to that point, look for an open in the ribbon cable (pin 10).

73,
Don W3FPR


> -----Original Message-----
>
>    I  need  some  help.  I  can  not  adjust  my power anymore when K2
is
>    connected   to   the  100  W  PA.  The  PA  is  overloaded  and
 power

>    meter shows 200 watt !!!
>
>    I tried  to switch off  PA in menu, but in this ca=e it is still
>    running with maximum QRP power.
>
>    I assume something goes wrong with VRFDET.
>
>    If I disconnect th= PA from K2 power adjustment works fine.
>
>    How could I investigate to find the reason for this fault ?
>
>    73 de Joerg (DL3QQ)
>

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[Don Wilhelm-3]

Jeorg,

There is one more place to check before replacing U6 - check to see if U6
pin 8 goes to almost 5 volts during transmit (this is the chip enable
signal) and check that pin 7 has the 5 volt supply on it.

If pin 8 does have the 5 volts, then the firmware is properly enabling the
chip, but if the voltage is not present, the problem goes back to the KPA100
firmware chip.

If pin 7 does not have 5 volts on pin 7, then that must be fixed first -
check the regulator at U3.  This latter possibility is not as likely since
the firmware chip uses this voltage too, and if you can turn the PA on and
off in the K2 menu, the firmware in the KPA100 is probably working.

73,
Don W3FPR


> -----Original Message-----

>
> Don,
>
> I checked the voltages during quick keydown.
>
> U5 pin 5     2,5 V
> U5 pin 7     2,5 V
> U6 pin 3     2,5 V
> U6 pin 6     0,06 V
>
> It looks like U6 is killed. Pin 6 does not show 2,5 V during transmit. I
> think I know what was happend ;-)
>
> I soldered a new cable for my KAT100 tuner to extent the length. I
> forgot to disconnect the AUX connector from K2 side. Pin 6 of U6 is
> connected to pin  7 of the AUX I/O port.
>
> I will replace U6 and test again.
>
>
> 73 de Joerg (DL3QQ)
>
> -----Original Message-----
> Date: Sun,  4 Jun 2006 04:30:01 +0200
> Subject: RE: [Elecraft] K2 power control
> From: "Don Wilhelm"
> To: , "Elecraft"
>
> Joerg,
>
> You either have something wrong with the wattmeter in the KPA100 or have
> something wrong in the path from the wattmeter forward power circuit to
> the
> VRFDET output from the KPA100.
>
> During a quick keydown period (with only the base K2 powered or with the
> PA
> turned off in the menu), check the following points on the KPA100 (in
> order)to determine at which point the voltage disappears - these should
> all
> be DC voltages - you should expect about 4 volts when the base K2 is
> developing 10 watts or more:
>
> U5 pin 5
> U5 pin 7
> U6 pin 3
> U6 pin 6
>
> U6 pin 6 is the KKPA100 output signal for the VRFDET line, and if you
> have
> voltage to that point, look for an open in the ribbon cable (pin 10).
>
> 73,
> Don W3FPR
>
>
> > -----Original Message-----
> >
> >    I  need  some  help.  I  can  not  adjust  my power anymore when K2
> is
> >    connected   to   the  100  W  PA.  The  PA  is  overloaded  and
>  power
> >    meter shows 200 watt !!!
> >
> >    I tried  to switch off  PA in menu, but in this ca=e it is still
> >    running with maximum QRP power.
> >
> >    I assume something goes wrong with VRFDET.
> >
> >    If I disconnect th= PA from K2 power adjustment works fine.
> >
> >    How could I investigate to find the reason for this fault ?
> >
> >    73 de Joerg (DL3QQ)
> >
>
>
>
>
> _______________________________________________
> Elecraft mailing list
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> You must be a subscriber to post to the list.
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>
>
> --
> No virus found in this incoming message.
> Checked by AVG Free Edition.
> Version: 7.1.394 / Virus Database: 268.8.1/355 - Release Date: 6/2/2006
>
>

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Don,

I checked U6.

pin 7 is okay - 5 V
pin 8 is strange - 5V always (receive and transmit)

I could not find a bridge somewhere on my board causing the 5V on pin 8.

It looks like output of my Firmware chip is defect.

This means I have to replace in my K2 Firmware chip and U6 :-(

Maybe you can not help, but someone else. My antenna tuner KAT100
doesn't work anymore since the same time when the problem starts in my
K2. The tuner is not recognized by K2 anymore. All LED's are dark and
you will not hear the typical clip of any relay.

I know in the meantime the reason for my problem. I mad a mistake in AUX
cable. The KAT100 got 12 V to the AUXBUS and 8V to the VRFDET. I assume
the Firmware chip and the EL5146c are also killed here.

I need to order spare parts from Elecraft in US to fix my problem. Is
there something else that can be tested before I make a final order to
Elecraft ?

73 de Joerg (DL3QQ)

-----Original Message-----
Date: Sun,  4 Jun 2006 14:49:21 +0200
Subject: RE: [Elecraft] K2 power control
From: "Don Wilhelm"
To: , , "Elecraft"

Jeorg,

There is one more place to check before replacing U6 - check to see if
U6
pin 8 goes to almost 5 volts during transmit (this is the chip enable
signal) and check that pin 7 has the 5 volt supply on it.

If pin 8 does have the 5 volts, then the firmware is properly enabling
the
chip, but if the voltage is not present, the problem goes back to the
KPA100
firmware chip.

If pin 7 does not have 5 volts on pin 7, then that must be fixed first -
check the regulator at U3.  This latter possibility is not as likely
since
the firmware chip uses this voltage too, and if you can turn the PA on
and
off in the K2 menu, the firmware in the KPA100 is probably working.

73,
Don W3FPR


> -----Original Message-----

>
> Don,
>
> I checked the voltages during quick keydown.
>
> U5 pin 5     2,5 V
> U5 pin 7     2,5 V
> U6 pin 3     2,5 V
> U6 pin 6     0,06 V
>
> It looks like U6 is killed. Pin 6 does not show 2,5 V during transmit.

I

> think I know what was happend ;-)
>
> I soldered a new cable for my KAT100 tuner to extent the length. I
> forgot to disconnect the AUX connector from K2 side. Pin 6 of U6 is
> connected to pin  7 of the AUX I/O port.
>
> I will replace U6 and test again.
>
>
> 73 de Joerg (DL3QQ)
>
> -----Original Message-----
> Date: Sun,  4 Jun 2006 04:30:01 +0200
> Subject: RE: [Elecraft] K2 power control
> From: "Don Wilhelm"
> To: , "Elecraft"
>
> Joerg,
>
> You either have something wrong with the wattmeter in the KPA100 or

have
> something wrong in the path from the wattmeter forward power circuit
to
> the
> VRFDET output from the KPA100.
>
> During a quick keydown period (with only the base K2 powered or with
the
> PA
> turned off in the menu), check the following points on the KPA100 (in
> order)to determine at which point the voltage disappears - these
should

> all
> be DC voltages - you should expect about 4 volts when the base K2 is
> developing 10 watts or more:
>
> U5 pin 5
> U5 pin 7
> U6 pin 3
> U6 pin 6
>
> U6 pin 6 is the KKPA100 output signal for the VRFDET line, and if you
> have
> voltage to that point, look for an open in the ribbon cable (pin 10).
>
> 73,
> Don W3FPR
>
>
> > -----Original Message-----
> >
> >    I  need  some  help.  I  can  not  adjust  my power anymore when

K2

> is
> >    connected   to   the  100  W  PA.  The  PA  is  overloaded  and
>  power
> >    meter shows 200 watt !!!
> >
> >    I tried  to switch off  PA in menu, but in this ca=e it is still
> >    running with maximum QRP power.
> >
> >    I assume something goes wrong with VRFDET.
> >
> >    If I disconnect th= PA from K2 power adjustment works fine.
> >
> >    How could I investigate to find the reason for this fault ?
> >
> >    73 de Joerg (DL3QQ)
> >
>
>
>
>
> _______________________________________________
> Elecraft mailing list
> 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
>
>
> --
> No virus found in this incoming message.
> Checked by AVG Free Edition.
> Version: 7.1.394 / Virus Database: 268.8.1/355 - Release Date:

6/2/2006
>
>




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