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Day 1: Fried something already?

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omehegan

Day 1: Fried something already?

Today I was finally able to get a real antenna set up to use with my
K2. Signals were coming in nicely on all bands so I decided to try and
make some QSOs. I have an external amplifier which I used with my old
rig, and it's keyed via an external carrier detect switch that sits in-
line between the rig and the amp. The switch takes 12v to work.

My first mistake may have been leaving the K2 turned on while I
changed the cabling to wire up the amp. Before this I was just running
the K2 to the antenna through my tuner. I hooked up the coax properly
from rig to switch to amp to tuner, and then applied 12v to the
switch. I heard a zap in my headphones, and quickly realized that I
had hooked the DC up to the RF switch backwards : ( I disconnected it
right away. Then I noticed that the noise level on 40m, where I had
been tuned, was greatly reduced. I removed the amp and switch from the
chain and connected the K2 to the tuner and antenna again. When I
tried to tune on 40, I got a high current warning. Same on 12 and 10.
The other bands work and sound fine.

I don't know how wiring the RF detect switch backwards could have
resulted in current getting into the K2. Maybe it was just static, I
don't know.

So I'm guessing I zapped something in the bandpass filter section of
the K2. I've opened it up but I don't see any visible signs of trauma.
I did smell a burnt electronics smell right after the mishap, but I'm
pretty sure it was from the RF detect switch and not the rig. Where
should I start with troubleshooting this?

*kicks self repeatedly*

--
[hidden email] (Owen B. Mehegan)
'There are more things in heaven and earth, Horatio,
Than are dreamt of in your philosophy.'
--William Shakespeare

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Don Wilhelm-4

Re: Day 1: Fried something already?

Owen,

Most likely the bandpass filter is just fine, I will take bets that you
effectively transmitted into an open load and something in the Low Pass
Filter is now awry - A shorted capacitor is my first suspicion - but
then you may have just zapped diodes in the KPA100 wattmeter.

But, break down the problem first. If you were driving an amplifier, I
suspect that you have the KPA100 installed (let me know if you do not).

Get out a dummy load and an external wattmeter - connect the external
wattmeter to the K2 and connect the wattmeter to the dummy load. Now
power only the base K2 through the 2.1mm coaxial power connector (remove
the APP connector from the KPA100).
Set power at 5 watts and do a TUNE.
Is the actual power output anywhere near 5 watts?, or is it above 10
watts? (or nearly zero?) Do you get any HI CUR warnings? How much power
does the K2 display indicate?
Answer those questions for each band.

The answers will give an indication of where to look next.

73,
Don W3FPR

On 11/7/2010 1:35 AM, Owen B. Mehegan wrote:

> My first mistake may have been leaving the K2 turned on while I
> changed the cabling to wire up the amp. Before this I was just running
> the K2 to the antenna through my tuner. I hooked up the coax properly
> from rig to switch to amp to tuner, and then applied 12v to the
> switch. I heard a zap in my headphones, and quickly realized that I
> had hooked the DC up to the RF switch backwards : ( I disconnected it
> right away. Then I noticed that the noise level on 40m, where I had
> been tuned, was greatly reduced. I removed the amp and switch from the
> chain and connected the K2 to the tuner and antenna again. When I
> tried to tune on 40, I got a high current warning. Same on 12 and 10.
> The other bands work and sound fine.
>
> I don't know how wiring the RF detect switch backwards could have
> resulted in current getting into the K2. Maybe it was just static, I
> don't know.
>
> So I'm guessing I zapped something in the bandpass filter section of
> the K2. I've opened it up but I don't see any visible signs of trauma.
> I did smell a burnt electronics smell right after the mishap, but I'm
> pretty sure it was from the RF detect switch and not the rig. Where
> should I start with troubleshooting this?
>

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omehegan

Re: Day 1: Fried something already?

Hello Don, thanks for your prompt reply (again - you helped me
diagnose my misplacement of C6 in the BPF section a couple of weeks
back).

I do not have the KPA100, just a base K2 with the SSB module added. I
was using an external Tokyo Hy-Power amp when this mishap occurred.

I've just done the test you described, with a wattmeter and a dummy
load. It's not as bad as I thought at first - only 40 seems affected.
No matter what power setting I choose on 40, when I press TUNE the K2
shows a high current warning, and then about .4 watts output, and the
needle on the wattmeter doesn't even flicker. All other bands can put
out their usual amounts of power with no problems.

--
[hidden email] (Owen B. Mehegan)
'I spent a lot of money on booze, birds and fast cars. The rest I just
squandered.'
--George Best

On Nov 7, 2010, at 4:59 AM, Don Wilhelm wrote:

> Owen,
>
> Most likely the bandpass filter is just fine, I will take bets that
> you effectively transmitted into an open load and something in the
> Low Pass Filter is now awry - A shorted capacitor is my first
> suspicion - but then you may have just zapped diodes in the KPA100
> wattmeter.
>
> But, break down the problem first. If you were driving an
> amplifier, I suspect that you have the KPA100 installed (let me know
> if you do not).
>
> Get out a dummy load and an external wattmeter - connect the
> external wattmeter to the K2 and connect the wattmeter to the dummy
> load. Now power only the base K2 through the 2.1mm coaxial power
> connector (remove the APP connector from the KPA100).
> Set power at 5 watts and do a TUNE.
> Is the actual power output anywhere near 5 watts?, or is it above 10
> watts? (or nearly zero?) Do you get any HI CUR warnings? How much
> power does the K2 display indicate?
> Answer those questions for each band.
>
> The answers will give an indication of where to look next.
>
> 73,
> Don W3FPR
>
> On 11/7/2010 1:35 AM, Owen B. Mehegan wrote:
>> My first mistake may have been leaving the K2 turned on while I
>> changed the cabling to wire up the amp. Before this I was just
>> running
>> the K2 to the antenna through my tuner. I hooked up the coax properly
>> from rig to switch to amp to tuner, and then applied 12v to the
>> switch. I heard a zap in my headphones, and quickly realized that I
>> had hooked the DC up to the RF switch backwards : ( I disconnected
>> it
>> right away. Then I noticed that the noise level on 40m, where I had
>> been tuned, was greatly reduced. I removed the amp and switch from
>> the
>> chain and connected the K2 to the tuner and antenna again. When I
>> tried to tune on 40, I got a high current warning. Same on 12 and 10.
>> The other bands work and sound fine.
>>
>> I don't know how wiring the RF detect switch backwards could have
>> resulted in current getting into the K2. Maybe it was just static, I
>> don't know.
>>
>> So I'm guessing I zapped something in the bandpass filter section of
>> the K2. I've opened it up but I don't see any visible signs of
>> trauma.
>> I did smell a burnt electronics smell right after the mishap, but I'm
>> pretty sure it was from the RF detect switch and not the rig. Where
>> should I start with troubleshooting this?
>>
>

Don Wilhelm-4

Re: Day 1: Fried something already?

Owen,

That all means that you have a problem with the 40 ,meter low pass
filter.L25, L26,C225, C226, C227, C228, C229 and the contacts of K12 are
all potential suspects that need to be checked.
One quick test would be to set to 40 meters and power off (the relays
are latching types) and measure the resistance between the center
conductor of the antenna jack and ground. If the inductors have
continuity, you should read close to zero ohms. If that is true, that
does not rule the inductors out entirely, but moves them lower on the
suspect list.

If you have no way to measure the capacitors, I might suggest that you
order all the components listed above and replace all of them - much
less frustration than trying each one at a time.

73,
Don W3FPR

On 11/7/2010 12:12 PM, Owen B. Mehegan wrote:

> Hello Don, thanks for your prompt reply (again - you helped me
> diagnose my misplacement of C6 in the BPF section a couple of weeks
> back).
>
> I do not have the KPA100, just a base K2 with the SSB module added. I
> was using an external Tokyo Hy-Power amp when this mishap occurred.
>
> I've just done the test you described, with a wattmeter and a dummy
> load. It's not as bad as I thought at first - only 40 seems affected.
> No matter what power setting I choose on 40, when I press TUNE the K2
> shows a high current warning, and then about .4 watts output, and the
> needle on the wattmeter doesn't even flicker. All other bands can put
> out their usual amounts of power with no problems.
>

omehegan

Re: Day 1: Fried something already?

I just tried the test for the inductors. With no antenna attached, I
read 1.7k ohms from antenna center conductor to ground (tuned 40
meters, then powered off). I am able to read continuity across L25 and
L26 though...

I think I can borrow a Fluke meter from a friend which can test
capacitors, so I'll try to do that.

--
[hidden email] (Owen B. Mehegan)
'When I was in sixth grade many years ago, I passed out after gym
class one day. When I woke up, I had vivid memories of cartoonish
bananas dancing around a red pool of blood, chanting 'E equals MC
squared' over and over.'
--Poster to ask.metafilter.com

On Nov 7, 2010, at 10:07 AM, Don Wilhelm wrote:

> Owen,
>
> That all means that you have a problem with the 40 ,meter low pass
> filter.L25, L26,C225, C226, C227, C228, C229 and the contacts of K12
> are all potential suspects that need to be checked.
> One quick test would be to set to 40 meters and power off (the
> relays are latching types) and measure the resistance between the
> center conductor of the antenna jack and ground. If the inductors
> have continuity, you should read close to zero ohms. If that is
> true, that does not rule the inductors out entirely, but moves them
> lower on the suspect list.
>
> If you have no way to measure the capacitors, I might suggest that
> you order all the components listed above and replace all of them -
> much less frustration than trying each one at a time.
>
> 73,
> Don W3FPR
>
> On 11/7/2010 12:12 PM, Owen B. Mehegan wrote:
>> Hello Don, thanks for your prompt reply (again - you helped me
>> diagnose my misplacement of C6 in the BPF section a couple of weeks
>> back).
>>
>> I do not have the KPA100, just a base K2 with the SSB module added. I
>> was using an external Tokyo Hy-Power amp when this mishap occurred.
>>
>> I've just done the test you described, with a wattmeter and a dummy
>> load. It's not as bad as I thought at first - only 40 seems affected.
>> No matter what power setting I choose on 40, when I press TUNE the K2
>> shows a high current warning, and then about .4 watts output, and the
>> needle on the wattmeter doesn't even flicker. All other bands can put
>> out their usual amounts of power with no problems.
>>
>

Don Wilhelm-4

Re: Day 1: Fried something already?

Owen,

Armed with that further information, I suspect the relay contacts.
Examine the inductors anyway to see if there is any evidence of charred
turns, if so, re-wind them.

You can check the relay contacts of K12 with an ohmmeter. If you set
the K2 to 40 meters, Relay K12 should be in the position opposite that
shown on the schematic. That means continuity between pins 7 and 8, and
3 and 4 - be aware that at DC, the entire low pass filter will measure
as a short to ground unless you lift lead # 3 or #4 from T4. Many have
drawn false conclusions because of this DC path to ground.

On 11/7/2010 1:37 PM, Owen B. Mehegan wrote:
> I just tried the test for the inductors. With no antenna attached, I
> read 1.7k ohms from antenna center conductor to ground (tuned 40
> meters, then powered off). I am able to read continuity across L25 and
> L26 though...
>
> I think I can borrow a Fluke meter from a friend which can test
> capacitors, so I'll try to do that.
>
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omehegan

Re: Day 1: Fried something already?

Hi Don -

Many thanks for your help! L25 and L26 look totally clean so I'm not
going to mess with them for the moment. I'll look into testing K12,
though I probably won't get to it until tomorrow. Can you clarify what
I should do to set up this test?

1. Tune the K2 to 40m
2. Power off
3. Check for continuity between pins 7-8 and 3-4 on K12.

Are you saying I need to lift one of the leads on T4 before doing this
test, or is that just a caution in the event that I see other anomalies?

--
[hidden email] (Owen B. Mehegan)
'I learned this, at least, by my experiment;
that if one advances confidently in the direction of his dreams,
and endeavors to live the life which he has imagined,
he will meet with a success unexpected in common hours.'
--Henry David Thoreau

On Nov 7, 2010, at 10:52 AM, Don Wilhelm wrote:

> Owen,
>
> Armed with that further information, I suspect the relay contacts.
> Examine the inductors anyway to see if there is any evidence of
> charred turns, if so, re-wind them.
>
> You can check the relay contacts of K12 with an ohmmeter. If you
> set the K2 to 40 meters, Relay K12 should be in the position
> opposite that shown on the schematic. That means continuity between
> pins 7 and 8, and 3 and 4 - be aware that at DC, the entire low
> pass filter will measure as a short to ground unless you lift lead #
> 3 or #4 from T4. Many have drawn false conclusions because of this
> DC path to ground.
>
> On 11/7/2010 1:37 PM, Owen B. Mehegan wrote:
>> I just tried the test for the inductors. With no antenna attached, I
>> read 1.7k ohms from antenna center conductor to ground (tuned 40
>> meters, then powered off). I am able to read continuity across L25
>> and
>> L26 though...
>>
>> I think I can borrow a Fluke meter from a friend which can test
>> capacitors, so I'll try to do that.
>>
>

Don Wilhelm-4

Re: Day 1: Fried something already?

Owen,

You have the procedure correct.

Yes, the caution about lifting one lead of T4 was if you want to
investigate the relay further.
Because of the ground at the secondary of T4, if the relay is set, you
will see zero ohms between all the pins except for the coil - that
should not surprise you.

73,
Don W3FPR

On 11/7/2010 3:06 PM, Owen B. Mehegan wrote:

> Hi Don -
>
> Many thanks for your help! L25 and L26 look totally clean so I'm not
> going to mess with them for the moment. I'll look into testing K12,
> though I probably won't get to it until tomorrow. Can you clarify what
> I should do to set up this test?
>
> 1. Tune the K2 to 40m
> 2. Power off
> 3. Check for continuity between pins 7-8 and 3-4 on K12.
>
> Are you saying I need to lift one of the leads on T4 before doing this
> test, or is that just a caution in the event that I see other anomalies?
>

omehegan

Re: Day 1: Fried something already?

Hi Don -

I've just had a look at K12 and I think it may be the culprit. First I
turned the K2 on, tuned it to 40m, then turned it off and unplugged
everything. I'm not positive I've got the pin numbering right, but no
two adjacent pins on a side have continuity right now, so I think the
diagnosis is correct. Looking at the relay from the top, I'm assuming
that the bottom left pin, when viewed with the writing right side up,
is 1. So when I flip the board over and look at the bottom with the
coax and power connectors pointing away from me, pin 1 is the top one
on the right of the two columns. I.e.:

(10) * * (1)
(9) * * (2)
(8) * * (3)
(7) * * (4)
(6) * * (5)

If this sounds right, I'll go ahead and order a replacement relay and
hope that's my only problem.

--
[hidden email] (Owen B. Mehegan)
'When I was in sixth grade many years ago, I passed out after gym
class one day. When I woke up, I had vivid memories of cartoonish
bananas dancing around a red pool of blood, chanting 'E equals MC
squared' over and over.'
--Poster to ask.metafilter.com

On Nov 7, 2010, at 1:28 PM, Don Wilhelm wrote:

> Owen,
>
> You have the procedure correct.
>
> Yes, the caution about lifting one lead of T4 was if you want to
> investigate the relay further.
> Because of the ground at the secondary of T4, if the relay is set,
> you will see zero ohms between all the pins except for the coil -
> that should not surprise you.
>
> 73,
> Don W3FPR

Don Wilhelm-4

Re: Day 1: Fried something already?

Owen,

That pin numbering is correct - it is just like an IC. From the top,
position the white bar to the left, and pin 1 will be the leftmost pin
toward you. On the bottom, you can usually identify pin 1 by the
different shaped solder pad. Normally pin 1 is round while the others
are rectangular.

On 11/10/2010 1:19 AM, Owen B. Mehegan wrote:

>
> Hi Don -
>
> I've just had a look at K12 and I think it may be the culprit. First I
> turned the K2 on, tuned it to 40m, then turned it off and unplugged
> everything. I'm not positive I've got the pin numbering right, but no
> two adjacent pins on a side have continuity right now, so I think the
> diagnosis is correct. Looking at the relay from the top, I'm assuming
> that the bottom left pin, when viewed with the writing right side up,
> is 1. So when I flip the board over and look at the bottom with the
> coax and power connectors pointing away from me, pin 1 is the top one
> on the right of the two columns. I.e.:
>
> (10) * * (1)
> (9) * * (2)
> (8) * * (3)
> (7) * * (4)
> (6) * * (5)
>
> If this sounds right, I'll go ahead and order a replacement relay and
> hope that's my only problem.
>

omehegan

Re: Day 1: Fried something already?

Well, I received my replacement parts today, but so far in spite of my
best efforts, I've been unable to desolder the K12 relay from my RF
board. I've used a combination of solder wick and a pump, and I can
see though the holes at this stage, but I still can't get the relay
free! What's the preferred method of doing this?

--
[hidden email] (Owen B. Mehegan)
'I learned this, at least, by my experiment;
that if one advances confidently in the direction of his dreams,
and endeavors to live the life which he has imagined,
he will meet with a success unexpected in common hours.'
--Henry David Thoreau

On Nov 10, 2010, at 4:45 AM, Don Wilhelm wrote:

> Owen,
>
> That pin numbering is correct - it is just like an IC. From the
> top, position the white bar to the left, and pin 1 will be the
> leftmost pin toward you. On the bottom, you can usually identify
> pin 1 by the different shaped solder pad. Normally pin 1 is round
> while the others are rectangular.
>
> On 11/10/2010 1:19 AM, Owen B. Mehegan wrote:
>>
>> Hi Don -
>>
>> I've just had a look at K12 and I think it may be the culprit.
>> First I
>> turned the K2 on, tuned it to 40m, then turned it off and unplugged
>> everything. I'm not positive I've got the pin numbering right, but no
>> two adjacent pins on a side have continuity right now, so I think the
>> diagnosis is correct. Looking at the relay from the top, I'm assuming
>> that the bottom left pin, when viewed with the writing right side up,
>> is 1. So when I flip the board over and look at the bottom with the
>> coax and power connectors pointing away from me, pin 1 is the top one
>> on the right of the two columns. I.e.:
>>
>> (10) * * (1)
>> (9) * * (2)
>> (8) * * (3)
>> (7) * * (4)
>> (6) * * (5)
>>
>> If this sounds right, I'll go ahead and order a replacement relay and
>> hope that's my only problem.
>>
>

AC7AC

Re: Day 1: Fried something already?

CONTENTS DELETED

The author has deleted this message.

Eric Champine

Re: Day 1: Fried something already?

In reply to this post by omehegan

Hey there.
I had to replace a relay a little while back and what I did was used a set
of pliers and crushed the top of the relay to the point where I could get in
and use flush cutting pliers to cut the bulk off. I was very careful not to
damage anything on the board or other components. Once done, I used the
pliers to grab the wire on the bottom of the board and put my soldering iron
on the top side of the board and applied heat. Came out very easy. When I
got the wire out of the hole I then cleaned it up with desolder braid. That
is what I did. Hope it helps.

73 de W2EEC

Eric
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omehegan

Re: Day 1: Fried something already?

In reply to this post by AC7AC

I had tried this a couple of times, but I kept at it and literally
just a couple of minutes after sending my email, finally I worked the
relay loose. Now I've replaced it, and 40m is working again!! I get
good transmit power and strong receive audio.

Thank you once again Don, that's twice you've saved my bacon with the
K2! I hope this is the last time : )

--
[hidden email] (Owen B. Mehegan)
'i am not a mathametician or computer programer ,but i do have
extremely advanced thoughts that i believe will help the human race'

On Nov 12, 2010, at 8:17 PM, Ron D'Eau Claire wrote:

> If you can see right through the holes, grab each pin and wiggle it.
> Even
> though there's no visible solder left, the thin film "tinning" each
> hole and
> the corresponding film on the inside of the plated hole can be
> surprisingly
> strong. Wiggle each pin separately and so it actually moves around
> in the
> hole a bit, then the relay should literally fall out.
>
> Ron AC7AC
>
> -----Original Message-----
> Well, I received my replacement parts today, but so far in spite of my
> best efforts, I've been unable to desolder the K12 relay from my RF
> board. I've used a combination of solder wick and a pump, and I can
> see though the holes at this stage, but I still can't get the relay
> free! What's the preferred method of doing this?
>
> --
>

Don Wilhelm-4

Re: Day 1: Fried something already?

Owen,

Glad to hear you were successful. In the future, the key is to "waste
the part", it is of much less value than the board. The one who posted
the advice to crush the relay with pliers (or whatever works) is "right
on the money". Preserve the board at all costs.

73,
Don W3FPR

On 11/12/2010 11:38 PM, Owen B. Mehegan wrote:
> I had tried this a couple of times, but I kept at it and literally
> just a couple of minutes after sending my email, finally I worked the
> relay loose. Now I've replaced it, and 40m is working again!! I get
> good transmit power and strong receive audio.
>
> Thank you once again Don, that's twice you've saved my bacon with the
> K2! I hope this is the last time : )
>
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Andrew Moore-3

Re: Day 1: Fried something already?

Glad you got it working. In the future, destroying the part *carefully* is
the way to go -- hack away at it with pliers, dremel, whatever. But do it
carefully:

- too much stress and prying can rip the vias and pads off the board,
leaving you with (possibly) a bigger problem than before

- if you're cutting or dremel'ing it away, you're probably showwering the
rest of board with tiny metal shavings

..
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AC7AC

Re: Day 1: Fried something already?

CONTENTS DELETED

The author has deleted this message.