Elecraft

[K2] Forgetful K2 filters

Classic

List

Threaded

7 messages Options

STEPHEN BUNTING

[K2] Forgetful K2 filters

Hi,

I have a K2/100 on my bench that is behaving strangely and I’d like some
advice. This has the SSB board and Z10000 buffer amp and 2.04P firmware.

That radio hasn’t been used for some time and I am told it was stored in an
attic space so will have been subject to temperature swings. Initial
symptoms were that the radio was deaf and filters misaligned.

Further investigation with spectrogram showed that all the CW filters were
centred at 900Hz and about 300Hz wide so I started a retune as per N0SS.
All re-tuned just fine and sensitivity returned. The SSB filters except OP1
were also misaligned but I haven’t touched them yet. As a CW op I was happy
to try the radio on the air.

But.....

When I turn the radio off and on again I find that my filter settings are
sometimes lost and the filters return to 900Hz centre and 300Hz wide.
Entering the cal fil routine can restore them without me readjusting the
DAC value.

Furthermore, when I am in user mode (i.e. not cal fil) and tap xfil to
scroll through the filters sequentially, every so often one filter ends up
back to the 900Hz center and 300Hz wide. This can be any of the four
defined filters. If I continue to scroll through the filter set I can
return to the erroneous filter to find that it is back where I wanted it to
be i.e. centered at 600Hz . This happens at random as far as I can tell i.e
any (or no) filter can misbehave in a cycle.

As an aside, when altering the BFO values to tune the filters I randomly l
got an “INFO 230” message even though the freq counter probe was in place.
This doesn't seem to be a loose connection as a repeat tune without
touching anything works just fine. I also have a random sidetone issue
which may be related. The sidetone disappears every so often and can be
brought back to life by changing the pitch slightly. If I increment ST P up
by 1 unit the sidetone reappears instantly. I can then return to my usual
level of 600Hz and it works again for a while.

The remarkable G3TJP has helped me enormously with all things Elecraft in
the past, but I feel bad about bothering him with another issue. Any
thoughts from the team here what to look at next? Replace the firmware chip?

73

Steve, M0BPQ
______________________________________________________________
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

Don Wilhelm-4

Re: [K2] Forgetful K2 filters

Steve,

That is truly erratic behavior. It sounds like either the EEPROM is
losing its data, or is having an addressing problem (the menu settings
are stored in EEPROM).

So in this particular case, I recommend you record the menu setting that
you care about and do a Master Reset (hold the 4, 5, and 6 buttons in
when powering on).
That should set the EEPROM contents back to the default settings.

If the settings do not stay after that, the next thing I would try is to
reflow the soldering on Control Board U6, U7 and U8 - particularly the
/EECS, SDO, and SCK signal lines.

After that, if it is still failing, I would first replace U7 and then U6
if necessary.

These are just guesses as to the possible cause, and I present the steps
in the order I would try. The order I choose is based on steps with
increasing difficulty and cost. You may choose any other order.

73,
Don W3FPR

On 4/17/2013 7:59 AM, STEPHEN BUNTING wrote:

> Hi,
>
> I have a K2/100 on my bench that is behaving strangely and I’d like some
> advice. This has the SSB board and Z10000 buffer amp and 2.04P firmware.
>
> That radio hasn’t been used for some time and I am told it was stored in an
> attic space so will have been subject to temperature swings. Initial
> symptoms were that the radio was deaf and filters misaligned.
>
> Further investigation with spectrogram showed that all the CW filters were
> centred at 900Hz and about 300Hz wide so I started a retune as per N0SS.
> All re-tuned just fine and sensitivity returned. The SSB filters except OP1
> were also misaligned but I haven’t touched them yet. As a CW op I was happy
> to try the radio on the air.
>
> But.....
>
> When I turn the radio off and on again I find that my filter settings are
> sometimes lost and the filters return to 900Hz centre and 300Hz wide.
> Entering the cal fil routine can restore them without me readjusting the
> DAC value.
>
> Furthermore, when I am in user mode (i.e. not cal fil) and tap xfil to
> scroll through the filters sequentially, every so often one filter ends up
> back to the 900Hz center and 300Hz wide. This can be any of the four
> defined filters. If I continue to scroll through the filter set I can
> return to the erroneous filter to find that it is back where I wanted it to
> be i.e. centered at 600Hz . This happens at random as far as I can tell i.e
> any (or no) filter can misbehave in a cycle.
>
> As an aside, when altering the BFO values to tune the filters I randomly l
> got an “INFO 230” message even though the freq counter probe was in place.
> This doesn't seem to be a loose connection as a repeat tune without
> touching anything works just fine. I also have a random sidetone issue
> which may be related. The sidetone disappears every so often and can be
> brought back to life by changing the pitch slightly. If I increment ST P up
> by 1 unit the sidetone reappears instantly. I can then return to my usual
> level of 600Hz and it works again for a while.
>
> The remarkable G3TJP has helped me enormously with all things Elecraft in
> the past, but I feel bad about bothering him with another issue. Any
> thoughts from the team here what to look at next? Replace the firmware chip?
>
> 73
>
> Steve, M0BPQ
> ______________________________________________________________
> 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
>

Chester Alderman

Re: [K2] Forgetful K2 filters

Just as an additional suggestion, since the unit has been in storage for a
period of time, maybe also change the battery that the EEPROM needs to
maintain its stored information?

73,
Tom - W4BQF

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Don Wilhelm
Sent: Wednesday, April 17, 2013 8:42 AM
To: STEPHEN BUNTING
Cc: [hidden email]
Subject: Re: [Elecraft] [K2] Forgetful K2 filters

Steve,

That is truly erratic behavior. It sounds like either the EEPROM is losing
its data, or is having an addressing problem (the menu settings are stored
in EEPROM).

So in this particular case, I recommend you record the menu setting that you
care about and do a Master Reset (hold the 4, 5, and 6 buttons in when
powering on).
That should set the EEPROM contents back to the default settings.

If the settings do not stay after that, the next thing I would try is to
reflow the soldering on Control Board U6, U7 and U8 - particularly the
/EECS, SDO, and SCK signal lines.

After that, if it is still failing, I would first replace U7 and then U6 if
necessary.

These are just guesses as to the possible cause, and I present the steps in
the order I would try. The order I choose is based on steps with increasing
difficulty and cost. You may choose any other order.

73,
Don W3FPR

On 4/17/2013 7:59 AM, STEPHEN BUNTING wrote:
> Hi,
>
> I have a K2/100 on my bench that is behaving strangely and I'd like
> some advice. This has the SSB board and Z10000 buffer amp and 2.04P
firmware.
>
> That radio hasn't been used for some time and I am told it was stored
> in an attic space so will have been subject to temperature swings.
> Initial symptoms were that the radio was deaf and filters misaligned.
>
> Further investigation with spectrogram showed that all the CW filters
> were centred at 900Hz and about 300Hz wide so I started a retune as per
N0SS.

> All re-tuned just fine and sensitivity returned. The SSB filters
> except OP1 were also misaligned but I haven't touched them yet. As a
> CW op I was happy to try the radio on the air.
>
> But.....
>
> When I turn the radio off and on again I find that my filter settings
> are sometimes lost and the filters return to 900Hz centre and 300Hz wide.
> Entering the cal fil routine can restore them without me readjusting
> the DAC value.
>
> Furthermore, when I am in user mode (i.e. not cal fil) and tap xfil to
> scroll through the filters sequentially, every so often one filter
> ends up back to the 900Hz center and 300Hz wide. This can be any of
> the four defined filters. If I continue to scroll through the filter
> set I can return to the erroneous filter to find that it is back where
> I wanted it to be i.e. centered at 600Hz . This happens at random as
> far as I can tell i.e any (or no) filter can misbehave in a cycle.
>
> As an aside, when altering the BFO values to tune the filters I
> randomly l got an "INFO 230" message even though the freq counter probe

was in place.

> This doesn't seem to be a loose connection as a repeat tune without
> touching anything works just fine. I also have a random sidetone issue
> which may be related. The sidetone disappears every so often and can
> be brought back to life by changing the pitch slightly. If I increment
> ST P up by 1 unit the sidetone reappears instantly. I can then return
> to my usual level of 600Hz and it works again for a while.
>
> The remarkable G3TJP has helped me enormously with all things Elecraft
> in the past, but I feel bad about bothering him with another issue.
> Any thoughts from the team here what to look at next? Replace the firmware

chip?

>
> 73
>
> Steve, M0BPQ
> ______________________________________________________________
> 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

______________________________________________________________
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

Don Wilhelm-4

Re: [K2] Forgetful K2 filters

Tom,

There is no battery - this is EEPROM, not battery backed RAM.

73,
Don W3FPR

On 4/17/2013 10:34 AM, Tommy wrote:
> Just as an additional suggestion, since the unit has been in storage for a
> period of time, maybe also change the battery that the EEPROM needs to
> maintain its stored information?
>
>

______________________________________________________________
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

Fred Townsend-2

Re: [K2] Forgetful K2 filters

In reply to this post by Don Wilhelm-4

Don: I do not own a K2 so I am shooting in the dark. On the other hand I
have designed and trouble shot circuits of this kind. Your analysis seems
dead on. Following your lead, are U6 & U7 socketed? If so the symptoms sound
very familiar. It's caused by soldering flux residues migrating to the
contact area of the socket. Time and temperature cycling can make this
happen. If true the sockets may need replacement. If removing and reseating
the chips changes calibration it is a dead giveaway. The chips can be saved
by cleaning in alcohol but cleaning the sockets is almost impossible. Just a
guess.
73
Fred, AE6QL

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Don Wilhelm
Sent: Wednesday, April 17, 2013 5:42 AM
To: STEPHEN BUNTING
Cc: [hidden email]
Subject: Re: [Elecraft] [K2] Forgetful K2 filters

Steve,

That is truly erratic behavior. It sounds like either the EEPROM is losing
its data, or is having an addressing problem (the menu settings are stored
in EEPROM).

So in this particular case, I recommend you record the menu setting that you
care about and do a Master Reset (hold the 4, 5, and 6 buttons in when
powering on).
That should set the EEPROM contents back to the default settings.

If the settings do not stay after that, the next thing I would try is to
reflow the soldering on Control Board U6, U7 and U8 - particularly the
/EECS, SDO, and SCK signal lines.

After that, if it is still failing, I would first replace U7 and then U6 if
necessary.

These are just guesses as to the possible cause, and I present the steps in
the order I would try. The order I choose is based on steps with increasing
difficulty and cost. You may choose any other order.

73,
Don W3FPR

On 4/17/2013 7:59 AM, STEPHEN BUNTING wrote:
> Hi,
>
> I have a K2/100 on my bench that is behaving strangely and I'd like
> some advice. This has the SSB board and Z10000 buffer amp and 2.04P
firmware.
>
> That radio hasn't been used for some time and I am told it was stored
> in an attic space so will have been subject to temperature swings.
> Initial symptoms were that the radio was deaf and filters misaligned.
>
> Further investigation with spectrogram showed that all the CW filters
> were centred at 900Hz and about 300Hz wide so I started a retune as per
N0SS.

was in place.

chip?

Don Wilhelm-4

Re: [K2] Forgetful K2 filters

Fred,

Only U6 is socketed, all the rest of the Control board ICs are to be
soldered.
If the builder followed instructions, the EEPROM U7 would be soldered
directly.
You are quite correct, sockets sometimes give trouble. Usually removing
U6 from the socket and re-inserting it will wipe the contacts
sufficiently to clear any oxidation that may have occurred during storage.

73,
Don W3FPR

On 4/17/2013 1:03 PM, Fred Townsend wrote:

> Don: I do not own a K2 so I am shooting in the dark. On the other hand I
> have designed and trouble shot circuits of this kind. Your analysis seems
> dead on. Following your lead, are U6 & U7 socketed? If so the symptoms sound
> very familiar. It's caused by soldering flux residues migrating to the
> contact area of the socket. Time and temperature cycling can make this
> happen. If true the sockets may need replacement. If removing and reseating
> the chips changes calibration it is a dead giveaway. The chips can be saved
> by cleaning in alcohol but cleaning the sockets is almost impossible. Just a
> guess.
> 73
> Fred, AE6QL
>
>

STEPHEN BUNTING

Re: [K2] Forgetful K2 filters

In reply to this post by STEPHEN BUNTING

Hi All,

To wrap up and put in the mail list archive, my K2 issues have now been
solved. Don, W3FPR suggested looking at U6, U7 and U8. I changed U7 whilst
the radio was apart and resoldered U6 and U8 to resolve the issue. AE6QL
also pointed out that there may be an issue with the socket for U6, but I
wasn't brave enough to try and remove it as Fred suggested in case I
trashed the board. So far I don't need to make that change. Phew!

Thanks again to the list for helping me with this issue.
73
Steve
M0BPQ

On 17 April 2013 12:59, STEPHEN BUNTING <[hidden email]> wrote:

> Hi,
>
> I have a K2/100 on my bench that is behaving strangely and I’d like some
> advice. This has the SSB board and Z10000 buffer amp and 2.04P firmware.
>
> That radio hasn’t been used for some time and I am told it was stored in
> an attic space so will have been subject to temperature swings. Initial
> symptoms were that the radio was deaf and filters misaligned.
>
> Further investigation with spectrogram showed that all the CW filters were
> centred at 900Hz and about 300Hz wide so I started a retune as per N0SS.
> All re-tuned just fine and sensitivity returned. The SSB filters except OP1
> were also misaligned but I haven’t touched them yet. As a CW op I was happy
> to try the radio on the air.
>
> But.....
>
> When I turn the radio off and on again I find that my filter settings are
> sometimes lost and the filters return to 900Hz centre and 300Hz wide.
> Entering the cal fil routine can restore them without me readjusting the
> DAC value.
>
> Furthermore, when I am in user mode (i.e. not cal fil) and tap xfil to
> scroll through the filters sequentially, every so often one filter ends up
> back to the 900Hz center and 300Hz wide. This can be any of the four
> defined filters. If I continue to scroll through the filter set I can
> return to the erroneous filter to find that it is back where I wanted it to
> be i.e. centered at 600Hz . This happens at random as far as I can tell i.e
> any (or no) filter can misbehave in a cycle.
>
> As an aside, when altering the BFO values to tune the filters I randomly l
> got an “INFO 230” message even though the freq counter probe was in place.
> This doesn't seem to be a loose connection as a repeat tune without
> touching anything works just fine. I also have a random sidetone issue
> which may be related. The sidetone disappears every so often and can be
> brought back to life by changing the pitch slightly. If I increment ST P up
> by 1 unit the sidetone reappears instantly. I can then return to my usual
> level of 600Hz and it works again for a while.
>
> The remarkable G3TJP has helped me enormously with all things Elecraft in
> the past, but I feel bad about bothering him with another issue. Any
> thoughts from the team here what to look at next? Replace the firmware chip?
>
> 73
>
> Steve, M0BPQ
>