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K2 no audio output on Part I Test

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VA2EK

K2 no audio output on Part I Test

Hey guys,

I'v started my part I test on my K2 S/N 007168, all is good except for the Audio Amplifier and Tone Generator Test section.

I hear nothing from the headphone jack, I've tried a couple of sets of head phones which works on other audio equipment, the headphones are in working condition.

I don't have a clue where to start looking except that I've looked closely at the board for bad soldering, if U9 was the right chip and installed properly and all that is good.

Thanks,

73's,

Mario - VA2EK.
[hidden email]
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Mario - VA2EK
K2/10 #7168
K3`100 #7741

Don Wilhelm-4

Re: K2 no audio output on Part I Test

Mario,

Look at the Control Board schematic in the lower right corner to see all
the components associated with U9 and check all of them for good
soldering. Also check P3 pins 7, 8, and 10.
RF board J8 pins 7, 8, and 10 are also in the path.

Be certain there is 12 volts at U9 pin 7.

73,
Don W3FPR

On 10/4/2012 4:18 PM, Mario Bouchard wrote:

> Hey guys,
>
> I'v started my part I test on my K2 S/N 007168, all is good except for the Audio Amplifier and Tone Generator Test section.
>
> I hear nothing from the headphone jack, I've tried a couple of sets of head phones which works on other audio equipment, the headphones are in working condition.
>
> I don't have a clue where to start looking except that I've looked closely at the board for bad soldering, if U9 was the right chip and installed properly and all that is good.
>
> Thanks,
>
> 73's,
>
> Mario - VA2EK.
> [hidden email]
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

______________________________________________________________
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VA2EK

Re: K2 no audio output on Part I Test

Don,

Thanks for the reply,

I checked on P3 #7 and #8, both have 5V, #10 has close to nothing (1.4mV) ???

I checked on J8 #7 and #8, both have 5V, #10 has close to nothing (1.4mV) ???

U9 #2 and #3 have 1.4mV, #6 has 6.5V has 13.6V.

Mario - VA2EK
K2/10 #7168
K3`100 #7741

Don Wilhelm-4

Re: K2 no audio output on Part I Test

Are you counting properly? Pins 7, 8, and 10 are connected together
according to the schematic.
The pins on one side are numbered 1, 3, 5, 7, etc. while the pins on the
other side are even numbers 2, 4, 6, 8, etc.

73,
Don W3FPR

On 10/4/2012 6:03 PM, VA2AAE wrote:

> Don,
>
> Thanks for the reply,
>
> I checked on P3 #7 and #8, both have 5V, #10 has close to nothing (1.4mV)
> ???
>
> I checked on J8 #7 and #8, both have 5V, #10 has close to nothing (1.4mV)
> ???
>
> U9 #2 and #3 have 1.4mV, #6 has 6.5V has 13.6V.
>
>
>
>
>
> -----
> Thanks,
>
> 73's
>
> Mario.
> --
> View this message in context: http://elecraft.365791.n2.nabble.com/K2-no-audio-output-on-Part-I-Test-tp7563701p7563705.html
> Sent from the Elecraft mailing list archive at Nabble.com.
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

VA2EK

Re: K2 no audio output on Part I Test

Don,

Thanks for indicating the right order of the pins, I had measured the wrong ones, rookie mistake I guess.

I just measured the voltage on J8 #7, #8 and #10, all have the same voltage, 5.2V.

I guess that's good, yes?

Mario Bouchard,

Envoyé de mon iPad
Sent from my iPad

On 2012-10-04, at 19:28, Don Wilhelm <[hidden email]> wrote:

> Are you counting properly? Pins 7, 8, and 10 are connected together according to the schematic.
> The pins on one side are numbered 1, 3, 5, 7, etc. while the pins on the other side are even numbers 2, 4, 6, 8, etc.
>
> 73,
> Don W3FPR
>
> On 10/4/2012 6:03 PM, VA2AAE wrote:
>> Don,
>>
>> Thanks for the reply,
>>
>> I checked on P3 #7 and #8, both have 5V, #10 has close to nothing (1.4mV)
>> ???
>>
>> I checked on J8 #7 and #8, both have 5V, #10 has close to nothing (1.4mV)
>> ???
>>
>> U9 #2 and #3 have 1.4mV, #6 has 6.5V has 13.6V.
>>
>>
>>
>>
>>
>> -----
>> Thanks,
>>
>> 73's
>>
>> Mario.
>> --
>> View this message in context: http://elecraft.365791.n2.nabble.com/K2-no-audio-output-on-Part-I-Test-tp7563701p7563705.html
>> Sent from the Elecraft mailing list archive at Nabble.com.
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>

Mario - VA2EK
K2/10 #7168
K3`100 #7741

Don Wilhelm-4

Re: K2 no audio output on Part I Test

Mario,

No, 5 volts there is not good at all. You should have zero volts DC,
but there may be some AC riding on that level. What is the voltage at
CB U9 pin 6?

I am thinking that either you have a solder bridge or you have a shorted
C29.

73,
Don W3FPR

On 10/4/2012 7:41 PM, Mario Bouchard wrote:

> Don,
>
> Thanks for indicating the right order of the pins, I had measured the wrong ones, rookie mistake I guess.
>
> I just measured the voltage on J8 #7, #8 and #10, all have the same voltage, 5.2V.
>
> I guess that's good, yes?
>
>
> Mario Bouchard,
>
> Envoyé de mon iPad
> Sent from my iPad
>
> On 2012-10-04, at 19:28, Don Wilhelm <[hidden email]> wrote:
>
>> Are you counting properly? Pins 7, 8, and 10 are connected together according to the schematic.
>> The pins on one side are numbered 1, 3, 5, 7, etc. while the pins on the other side are even numbers 2, 4, 6, 8, etc.
>>
>> 73,
>> Don W3FPR
>>
>> On 10/4/2012 6:03 PM, VA2AAE wrote:
>>> Don,
>>>
>>> Thanks for the reply,
>>>
>>> I checked on P3 #7 and #8, both have 5V, #10 has close to nothing (1.4mV)
>>> ???
>>>
>>> I checked on J8 #7 and #8, both have 5V, #10 has close to nothing (1.4mV)
>>> ???
>>>
>>> U9 #2 and #3 have 1.4mV, #6 has 6.5V has 13.6V.
>>>
>>>
>>>
>>>
>>>
>>> -----
>>> Thanks,
>>>
>>> 73's
>>>
>>> Mario.
>>> --
>>> View this message in context: http://elecraft.365791.n2.nabble.com/K2-no-audio-output-on-Part-I-Test-tp7563701p7563705.html
>>> Sent from the Elecraft mailing list archive at Nabble.com.
>>> ______________________________________________________________
>>> Elecraft mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>>> Help: http://mailman.qth.net/mmfaq.htm
>>> Post: mailto:[hidden email]
>>>
>>> This list hosted by: http://www.qsl.net
>>> Please help support this email list: http://www.qsl.net/donate.html
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

VA2EK

Re: K2 no audio output on Part I Test

Don,

CB U9 #2 and #3 have 1.4mV, #6 has 6.5V and #7 has 13.6V.

Thanks,

Mario Bouchard,

Envoyé de mon iPad
Sent from my iPad

On 2012-10-04, at 20:28, Don Wilhelm <[hidden email]> wrote:

> U9 #2 and #3 have 1.4mV, #6 has 6.5V has 13.6V.
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Mario - VA2EK
K2/10 #7168
K3`100 #7741

Don Wilhelm-4

Re: K2 no audio output on Part I Test

Mario,

Yes, U9 pin 6 can have 6.5 volts, but...
There is capacitor C29 between U9 pin 6 and the AF OUT signal (and the
headphone jack) that should block any DC. If you have 5 volts at the AF
OUT signal (P3 pins 7, 8 and 10), then that is a problem.

You have something shorted to another signal or power supply rail
somewhere. Your challenge is to find it.

73,
Don W3FPR

On 10/4/2012 8:38 PM, Mario Bouchard wrote:

> Don,
>
> CB U9 #2 and #3 have 1.4mV, #6 has 6.5V and #7 has 13.6V.
>
> Thanks,
>
>
> Mario Bouchard,
>
> Envoyé de mon iPad
> Sent from my iPad
>
> On 2012-10-04, at 20:28, Don Wilhelm <[hidden email]> wrote:
>
>> U9 #2 and #3 have 1.4mV, #6 has 6.5V has 13.6V.
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

VA2EK

Re: K2 no audio output on Part I Test

Don,

Thanks for your assistance, it's greatly appreciated, I'll review everything thoroughly once more. I'll let you know what I find.

73's

Mario Bouchard,

Envoyé de mon iPad
Sent from my iPad

On 2012-10-04, at 20:46, Don Wilhelm <[hidden email]> wrote:

> Mario,
>
> Yes, U9 pin 6 can have 6.5 volts, but...
> There is capacitor C29 between U9 pin 6 and the AF OUT signal (and the headphone jack) that should block any DC. If you have 5 volts at the AF OUT signal (P3 pins 7, 8 and 10), then that is a problem.
>
> You have something shorted to another signal or power supply rail somewhere. Your challenge is to find it.
>
> 73,
> Don W3FPR
>
> On 10/4/2012 8:38 PM, Mario Bouchard wrote:
>> Don,
>>
>> CB U9 #2 and #3 have 1.4mV, #6 has 6.5V and #7 has 13.6V.
>>
>> Thanks,
>>
>>
>> Mario Bouchard,
>>
>> Envoyé de mon iPad
>> Sent from my iPad
>>
>> On 2012-10-04, at 20:28, Don Wilhelm <[hidden email]> wrote:
>>
>>> U9 #2 and #3 have 1.4mV, #6 has 6.5V has 13.6V.
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>

Mario - VA2EK
K2/10 #7168
K3`100 #7741