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K2 Transmitter Alignment

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Doug Person

K2 Transmitter Alignment

I have completed Transmitter alignment. With the power set to two watts
- I get 2 watts or better on all bands except 17 where I get only .5
watts out regardless of the power setting.

Any help appreciated.

Thanks,

Doug -- K0DXV
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Don Wilhelm-3

RE: K2 Transmitter Alignment

Doug,

The only thing unique to 17 meters is the 15/17 m bandpass filter and the
17/15 m Low Pass filter, and I would suspect the bandpass filter as the most
likely.

Look first at the slugs of L10 and L11 - they should be about the same
distance down from the top of the cans - if they are not, check capacitors
C30, C31, C35 and C36 for proper values and proper soldering.

If the slugs are the same distance down in the cans (within a half turn),
then check the trimmers C32 and C34. The trimmers will normally be set
close (within 20 degrees of rotation) to the midpoint - the slots in the
trimmers perpendicular to the flat side. If that is not the case (and the
checks above for the 15 meter tuning are correct), then the most likely
thing is a soldering problem at relay K6 or trimmer capacitors C32 and C34.

Look at the RF Board schematic sheet 3, and on the left side find the 15/17m
bandpass filter. Check all the components shown in that schematic area for
proper soldering and correct values. Include relay K6.

73,
Don W3FPR

> -----Original Message-----
>
> I have completed Transmitter alignment. With the power set to two watts
> - I get 2 watts or better on all bands except 17 where I get only .5
> watts out regardless of the power setting.
>
> Any help appreciated.
>
> Thanks,
>
> Doug -- K0DXV
>

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Doug Person

Re: K2 Transmitter Alignment

Hi Don,

I found the problem. and you were right - it was the bandpass filter.
I had C220 and C221 reversed. After a bit of fooling around and
realigning, 17 is OK.

What I now have is generally low output. About 9 watts 80 through 20, 6
watts on 15 and only 3.5 on 12 and 10.

Any thoughts?

Thanks & 73,

Doug -- K0DXV

Don Wilhelm wrote:

> Doug,
>
> The only thing unique to 17 meters is the 15/17 m bandpass filter and the
> 17/15 m Low Pass filter, and I would suspect the bandpass filter as the most
> likely.
>
> Look first at the slugs of L10 and L11 - they should be about the same
> distance down from the top of the cans - if they are not, check capacitors
> C30, C31, C35 and C36 for proper values and proper soldering.
>
> If the slugs are the same distance down in the cans (within a half turn),
> then check the trimmers C32 and C34. The trimmers will normally be set
> close (within 20 degrees of rotation) to the midpoint - the slots in the
> trimmers perpendicular to the flat side. If that is not the case (and the
> checks above for the 15 meter tuning are correct), then the most likely
> thing is a soldering problem at relay K6 or trimmer capacitors C32 and C34.
>
> Look at the RF Board schematic sheet 3, and on the left side find the 15/17m
> bandpass filter. Check all the components shown in that schematic area for
> proper soldering and correct values. Include relay K6.
>
> 73,
> Don W3FPR
>
>
>> -----Original Message-----
>>
>> I have completed Transmitter alignment. With the power set to two watts
>> - I get 2 watts or better on all bands except 17 where I get only .5
>> watts out regardless of the power setting.
>>
>> Any help appreciated.
>>
>> Thanks,
>>
>> Doug -- K0DXV
>>
>>
>
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
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>
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com
>
>
>

Don Wilhelm-3

RE: K2 Transmitter Alignment

Doug,

First, what is your power supply voltage? Is it sagging during transmit?
An easy way to check is the tap the DISPLAY button and then enter tune - the
display will show you the voltage and current. If the voltage is sagging
low, blame your power supply or the connecting cable.

If the voltage is good (12.5 to 13.8 volts) during transmit, then you do
have a problem with the transmit chain gain. Check T1, T2, T3 and T4
carefully. Make certain they are wound with the proper number of turns and
look like the diagrams in the manual.

If all is OK in the above checks, then the problem source will have to be
found the hard way. The first step is to make up the RF Probe shown in
Appendix E of the K2 manual (parts are included with the kit). If you have
a good 'scope, you can use that rather than the RF Probe. What you will
need to do is go through the Transmit Signal Tracing procedure in the K2
manual Appendix E. You will be looking for the stage where the RF voltage
becomes significantly less than the expected value listed. If you need
assistance with this signal tracing procedure, just ask and we can provide
more details.

73,
Don W3FPR

> -----Original Message-----
> From: Doug Person [mailto:[hidden email]]
> Sent: Tuesday, November 21, 2006 6:35 PM
> To: [hidden email]
> Cc: [hidden email]
> Subject: Re: [Elecraft] K2 Transmitter Alignment
>
>
> Hi Don,
>
> I found the problem. and you were right - it was the bandpass filter.
> I had C220 and C221 reversed. After a bit of fooling around and
> realigning, 17 is OK.
>
> What I now have is generally low output. About 9 watts 80 through 20, 6
> watts on 15 and only 3.5 on 12 and 10.
>
> Any thoughts?
>
> Thanks & 73,
>
> Doug -- K0DXV
>
> Don Wilhelm wrote:
> > Doug,
> >
> > The only thing unique to 17 meters is the 15/17 m bandpass
> filter and the
> > 17/15 m Low Pass filter, and I would suspect the bandpass
> filter as the most
> > likely.
> >
> > Look first at the slugs of L10 and L11 - they should be about the same
> > distance down from the top of the cans - if they are not, check
> capacitors
> > C30, C31, C35 and C36 for proper values and proper soldering.
> >
> > If the slugs are the same distance down in the cans (within a
> half turn),
> > then check the trimmers C32 and C34. The trimmers will normally be set
> > close (within 20 degrees of rotation) to the midpoint - the slots in the
> > trimmers perpendicular to the flat side. If that is not the
> case (and the
> > checks above for the 15 meter tuning are correct), then the most likely
> > thing is a soldering problem at relay K6 or trimmer capacitors
> C32 and C34.
> >
> > Look at the RF Board schematic sheet 3, and on the left side
> find the 15/17m
> > bandpass filter. Check all the components shown in that
> schematic area for
> > proper soldering and correct values. Include relay K6.
> >
> > 73,
> > Don W3FPR
> >
> >
> >> -----Original Message-----
> >>
> >> I have completed Transmitter alignment. With the power set to
> two watts
> >> - I get 2 watts or better on all bands except 17 where I get only .5
> >> watts out regardless of the power setting.
> >>
> >> Any help appreciated.
> >>
> >> Thanks,
> >>
> >> Doug -- K0DXV
> >>
> >>
> >
> > _______________________________________________
> > 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: 7.1.409 / Virus Database: 268.14.7/538 - Release Date: 11/18/2006
>
>

Doug Person

Re: K2 Transmitter Alignment

Don,

Voltage is fine. Running on a quality 25 amp ps. No scope here so I'll
try the putting the probe together and see what I can determine.

Many Thanks

Doug -- K0DXV

Don Wilhelm wrote:

> Doug,
>
> First, what is your power supply voltage? Is it sagging during transmit?
> An easy way to check is the tap the DISPLAY button and then enter tune - the
> display will show you the voltage and current. If the voltage is sagging
> low, blame your power supply or the connecting cable.
>
> If the voltage is good (12.5 to 13.8 volts) during transmit, then you do
> have a problem with the transmit chain gain. Check T1, T2, T3 and T4
> carefully. Make certain they are wound with the proper number of turns and
> look like the diagrams in the manual.
>
> If all is OK in the above checks, then the problem source will have to be
> found the hard way. The first step is to make up the RF Probe shown in
> Appendix E of the K2 manual (parts are included with the kit). If you have
> a good 'scope, you can use that rather than the RF Probe. What you will
> need to do is go through the Transmit Signal Tracing procedure in the K2
> manual Appendix E. You will be looking for the stage where the RF voltage
> becomes significantly less than the expected value listed. If you need
> assistance with this signal tracing procedure, just ask and we can provide
> more details.
>
> 73,
> Don W3FPR
>
>
>> -----Original Message-----
>> From: Doug Person [mailto:[hidden email]]
>> Sent: Tuesday, November 21, 2006 6:35 PM
>> To: [hidden email]
>> Cc: [hidden email]
>> Subject: Re: [Elecraft] K2 Transmitter Alignment
>>
>>
>> Hi Don,
>>
>> I found the problem. and you were right - it was the bandpass filter.
>> I had C220 and C221 reversed. After a bit of fooling around and
>> realigning, 17 is OK.
>>
>> What I now have is generally low output. About 9 watts 80 through 20, 6
>> watts on 15 and only 3.5 on 12 and 10.
>>
>> Any thoughts?
>>
>> Thanks & 73,
>>
>> Doug -- K0DXV
>>
>> Don Wilhelm wrote:
>>
>>> Doug,
>>>
>>> The only thing unique to 17 meters is the 15/17 m bandpass
>>>
>> filter and the
>>
>>> 17/15 m Low Pass filter, and I would suspect the bandpass
>>>
>> filter as the most
>>
>>> likely.
>>>
>>> Look first at the slugs of L10 and L11 - they should be about the same
>>> distance down from the top of the cans - if they are not, check
>>>
>> capacitors
>>
>>> C30, C31, C35 and C36 for proper values and proper soldering.
>>>
>>> If the slugs are the same distance down in the cans (within a
>>>
>> half turn),
>>
>>> then check the trimmers C32 and C34. The trimmers will normally be set
>>> close (within 20 degrees of rotation) to the midpoint - the slots in the
>>> trimmers perpendicular to the flat side. If that is not the
>>>
>> case (and the
>>
>>> checks above for the 15 meter tuning are correct), then the most likely
>>> thing is a soldering problem at relay K6 or trimmer capacitors
>>>
>> C32 and C34.
>>
>>> Look at the RF Board schematic sheet 3, and on the left side
>>>
>> find the 15/17m
>>
>>> bandpass filter. Check all the components shown in that
>>>
>> schematic area for
>>
>>> proper soldering and correct values. Include relay K6.
>>>
>>> 73,
>>> Don W3FPR
>>>
>>>
>>>
>>>> -----Original Message-----
>>>>
>>>> I have completed Transmitter alignment. With the power set to
>>>>
>> two watts
>>
>>>> - I get 2 watts or better on all bands except 17 where I get only .5
>>>> watts out regardless of the power setting.
>>>>
>>>> Any help appreciated.
>>>>
>>>> Thanks,
>>>>
>>>> Doug -- K0DXV
>>>>
>>>>
>>>>
>>> _______________________________________________
>>> 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: 7.1.409 / Virus Database: 268.14.7/538 - Release Date: 11/18/2006
>>
>>
>>
>
> _______________________________________________
> 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
>
>
>

Doug Person

Re: K2 Transmitter Alignment

In reply to this post by Don Wilhelm-3

Hi Don and all,

As stated in a previous note, my K2 is finished and working but I am not
getting full output. With power set to max I get 9 to 10 watts on 80 to
20, 6 watts on 15 and 3.5 watts on 12 and 10.

I went through the "Transmit Mixer, Buffer, Band-Pass Filter, T-R
Switch" troubleshooting section on page 14 of Appendix E. All voltages
appear much lower then the indicated "expected" values. There's not
much information about how to interpret these readings. Also, the 1N34A
supplied with the rf probe appears to be defective. I replaced it with
one on hand. I'm not sure if all 1N34A's are essentially identical and
interchangeable or that I might have introduced another variable that is
throwing the voltage readings off. With output power set at 5 watts at
7.000 and 5 watts or better indicated on the output power meter - here's
what I have:

U10 pin 4: brief value rapidly goes to zero
U9 pin 6: .011
W6: .004
anode D1: .004
collector Q5: .032
base Q6: .021
base Q7: .12
base Q8: .142
anode D9: .473

Thanks for any help,

Doug -- KØDXV

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Don Wilhelm-3

RE: K2 Transmitter Alignment

Doug,

Yes, your values are significantly lower than what is expected.
The first value - Tx Mixer output (U10 pin 4) says that something is wrong
with either the mixer itself or its inputs.

Go back a bit and do the VCO checks and BFO checks indicated in the lower
part of Receiver Signal Tracing on page 10 of Appendix E. Continue through
the BFO checks shown on page 11. Also check the RF voltage at U10 pin 1
after measuring the BFO RF Voltage at TP2 (and before exiting from the CAL
FIL menu). It should be nearly the same as the RF voltage measured at TP2.
Then check the TX VCO RF voltage at U10 pin 6, it should be in the range of
0.3 to 0.4 volts.

If you replaced the 1N34A diode with a good one, all should be well with the
RF Probe.

73,
Don W3FPR

> -----Original Message-----
>
> Hi Don and all,
>
> As stated in a previous note, my K2 is finished and working but I am not
> getting full output. With power set to max I get 9 to 10 watts on 80 to
> 20, 6 watts on 15 and 3.5 watts on 12 and 10.
>
> I went through the "Transmit Mixer, Buffer, Band-Pass Filter, T-R
> Switch" troubleshooting section on page 14 of Appendix E. All voltages
> appear much lower then the indicated "expected" values. There's not
> much information about how to interpret these readings. Also, the 1N34A
> supplied with the rf probe appears to be defective. I replaced it with
> one on hand. I'm not sure if all 1N34A's are essentially identical and
> interchangeable or that I might have introduced another variable that is
> throwing the voltage readings off. With output power set at 5 watts at
> 7.000 and 5 watts or better indicated on the output power meter - here's
> what I have:
>
> U10 pin 4: brief value rapidly goes to zero
> U9 pin 6: .011
> W6: .004
> anode D1: .004
> collector Q5: .032
> base Q6: .021
> base Q7: .12
> base Q8: .142
> anode D9: .473
>
> Thanks for any help,
>
> Doug -- KØDXV
>

Doug Person

Re: K2 Transmitter Alignment

Don,

Measurements from Receiver Signal Tracing:

U4 P4 = .164
U3 P3 = .08
U3 P6 = .163
U11 P6 .144
TP2 = .012
U10 P6 = .032

The K2 manual outlines this test process but doesn't provide any insight
into what the causes might be if the voltages are different then what is
expected.

Thanks for your help.

73, Doug -- KØDXV

Don Wilhelm wrote:

> Doug,
>
> Yes, your values are significantly lower than what is expected.
> The first value - Tx Mixer output (U10 pin 4) says that something is wrong
> with either the mixer itself or its inputs.
>
> Go back a bit and do the VCO checks and BFO checks indicated in the lower
> part of Receiver Signal Tracing on page 10 of Appendix E. Continue through
> the BFO checks shown on page 11. Also check the RF voltage at U10 pin 1
> after measuring the BFO RF Voltage at TP2 (and before exiting from the CAL
> FIL menu). It should be nearly the same as the RF voltage measured at TP2.
> Then check the TX VCO RF voltage at U10 pin 6, it should be in the range of
> 0.3 to 0.4 volts.
>
> If you replaced the 1N34A diode with a good one, all should be well with the
> RF Probe.
>
> 73,
> Don W3FPR
>
>
>> -----Original Message-----
>>
>> Hi Don and all,
>>
>> As stated in a previous note, my K2 is finished and working but I am not
>> getting full output. With power set to max I get 9 to 10 watts on 80 to
>> 20, 6 watts on 15 and 3.5 watts on 12 and 10.
>>
>> I went through the "Transmit Mixer, Buffer, Band-Pass Filter, T-R
>> Switch" troubleshooting section on page 14 of Appendix E. All voltages
>> appear much lower then the indicated "expected" values. There's not
>> much information about how to interpret these readings. Also, the 1N34A
>> supplied with the rf probe appears to be defective. I replaced it with
>> one on hand. I'm not sure if all 1N34A's are essentially identical and
>> interchangeable or that I might have introduced another variable that is
>> throwing the voltage readings off. With output power set at 5 watts at
>> 7.000 and 5 watts or better indicated on the output power meter - here's
>> what I have:
>>
>> U10 pin 4: brief value rapidly goes to zero
>> U9 pin 6: .011
>> W6: .004
>> anode D1: .004
>> collector Q5: .032
>> base Q6: .021
>> base Q7: .12
>> base Q8: .142
>> anode D9: .473
>>
>> Thanks for any help,
>>
>> Doug -- KØDXV
>>
>>
>
> _______________________________________________
> 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
>
>
>

Doug Person

Re: K2 Transmitter Alignment

In reply to this post by Don Wilhelm-3

One thing that I'm finding a problem is I'm running through all the
voltage checks in the receiver. They're all really low. But other than
the one reference to the BFO possibly being set incorrectly, (its not)
there is not one hint anywhere as to what the cause might be. So, I
have an affect but no causes. I still have no clue why every voltage in
both the receiver and transmitter seems extremely low. despite this, the
receiver seems to receive fine and the only manifestation of the problem
is low transmitter output. There most be some common cause to all of
this. But so far I have no idea what it is.

Doug -- K0DXV

Don Wilhelm wrote: