KPA100 stripped final's screw removal

[Bob Evans-4]

Hi Folks,

 

This may not be a very high tech solution, but it got me out of a perceived
pickle.  I had stripped one of the screws securing the final transistors to
the heat sink in one of my K2/100s.  I was thinking "how the heck am I going
to remove a stripped screw in such a tight space?".  A friend had suggested
super gluing a Phillips screwdriver into the stripped screw.  I tried it and
the super glue didn't hold.  Then I thought I could drill and tap the screw
out, but I couldn't find a tap that was small enough.  What finally worked
was simply to drill into the center of the screw until the screw head
detached from the screw shaft.  It took a 5/64" bit.  I had loosened all the
other screws on the board and the board simply lifted away from the heat
sink when the screw head separated from the shaft.  With the board removed,
the screw shaft could easily be unscrewed from the heat sink and replaced
with a new screw.  By the way, I turned the KPA100 board screw-head-down
when I drilled so there wouldn't be much of a chance for metal splinters
getting into the board.  It worked!

 

I have always used a high quality #1 screwdriver when I tightened these
screws, but it stripped out anyway.  I use my K2/100s exclusively for
contesting and have been finding I need to re-tighten those screws after
20-30 hours of full bore operating (100 watts, lots of CQs).  Maybe a
Lock-tight type product is needed to keep the screws from backing out after
thermal cycling, but some of you may have some advice whether this should be
done or not.  Anyway, in case you find your final's screw stripped, this
method worked for me.

 

P.S.  I played around in ARRL SS SSB this past weekend.  The K2 is a GREAT
side band radio too!  I know, I know.I can get ejected from this reflector
for such heresy.  ;-)

 

73,

Bob K5WA

K2s #4687 and #5119 in SO2R configuration

 

 

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[Bekir Kemal Ataman]

>P.S.  I played around in ARRL SS SSB this past weekend.  The K2 is a GREAT
>side band radio too!  I know, I know.I can get ejected from this reflector
>for such heresy.  ;-)

Why? Is this a CW-only list? I am not very good in CW and I joined this
list because I think K2 is a great SSB radio. If it is a CW-only place,
then I am sorry for joining in. I'll unsubscribe straight away.

73!
BKA (TA2RX)

----------------------------------
Bekir Kemal Ataman
ArchiMac BBS Sysop & Webmaster <http://www.archimac.org/>


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[Ron D'Eau Claire-2]

Not "just" SSB, but a number of SSB operators running from QRPp to the legal
limit (and those impatiently still at 100 watts while waiting for the
long-awaited Elecraft amplifier!).

Ron AC7AC

-----Original Message-----

>P.S.  I played around in ARRL SS SSB this past weekend.  The K2 is a
>GREAT side band radio too!  I know, I know.I can get ejected from this
>reflector for such heresy.  ;-)

Why? Is this a CW-only list? I am not very good in CW and I joined this list
because I think K2 is a great SSB radio. If it is a CW-only place, then I am
sorry for joining in. I'll unsubscribe straight away.

73!
BKA (TA2RX)

----------------------------------
Bekir Kemal Ataman
ArchiMac BBS Sysop & Webmaster <http://www.archimac.org/>

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[David F. Reed]

Bekir,

I think many "Elekrafters" enjoy CW because the radios (K1, KX1, K2)
have such nice characteristics as CW rigs; I admit my first few contacts
with my K2 were SSB though, even though I enjoy CW plenty, and have
worked several contests as CW only, QRP category...

I think most will welcome you here, and the cw / ssb rivalry is all in
fun (or so it seems to me).

So what antenna(s) are you using with your K2, and what bands are you
using it most on?

73 de W5SV, Dave

Bekir Kemal Ataman wrote:

>>P.S.  I played around in ARRL SS SSB this past weekend.  The K2 is a GREAT
>>side band radio too!  I know, I know.I can get ejected from this reflector
>>for such heresy.  ;-)
>>    
>>
>
>Why? Is this a CW-only list? I am not very good in CW and I joined this
>list because I think K2 is a great SSB radio. If it is a CW-only place,
>then I am sorry for joining in. I'll unsubscribe straight away.
>
>73!
>BKA (TA2RX)
>
>----------------------------------
>Bekir Kemal Ataman
>ArchiMac BBS Sysop & Webmaster <http://www.archimac.org/>
>  
>

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[Bekir Kemal Ataman]

>I think many "Elekrafters" enjoy CW because the radios (K1, KX1, K2)
>have such nice characteristics as CW rigs

I can understand people preferring CW because of having CW Rigs and vice
versa but if it is reaching a point of ejecting/rejecting others for not
having the same preferences then we have got a problem.

>I think most will welcome you here, and the cw / ssb rivalry is all in
>fun (or so it seems to me).

I just hope it is. Otherwise I'd really be disappointed.

>So what antenna(s) are you using with your K2, and what bands are you
>using it most on?

I have got a 4-band inverted-V on 10, 20, 40 and 80 meters about 20 meters
off the ground. I managed to get SWRs less than 1.2 on all bands after
struggling for a few weeks on the roof of our apartment block. It seems it
was worth the trouble.

Although my QTH is blocked by a nearby hill in the East and another nearish
hill in the North, I have worked quite a few countries with less than 8
Watts. (My rig does not go above 7.1 to 7.3 Watts, giving a Hi Cur warning.
I just hope this is normal. Cal Cur is set at 3.5 Ampers)

When I could hear the stations early enough, I have managed to contact a
few Japanese stations, too. When I am little late, my signals get lost in
the pileup. The European DX Net organized by I2ZGC, Gianni helped me make
contact with a few North African stations but I could not hear/get heard by
stations in South Africa nor Indonesia. I sometimes hear a few North
American stations early in the morning but even then they are very weak
most of the time.

I work on 40 and 80 meters at night and 20 meters during the day, mostly. I
could not hear anyone on 10 meters so far. It seems to be very quite in
this part of the world. Perhaps I just wonder around the wrong frequencies
or just at the wrong time. I cannot go in the air very often because of
work load during the week and because of XYL QRM at weekends but I try to
join contests whenever I can. It is great fun.

I am now looking forward to the European QSO Party. If we can manage the
contacts properly, an SSB version might start soon.

73!
BKA (TA2RX)

----------------------------------
Bekir Kemal Ataman
ArchiMac BBS Sysop & Webmaster <http://www.archimac.org/>


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[Don Brown-4]

Hi

I believe the screws loosen due to the thermal pads compressing not the
screws backing off. The lock washers should prevent the screws from backing
off and locktite may make the screws impossible to remove. Once the pads are
fully compressed the screws should not loosen, but it may take a couple of
times at 10-20 hour operation intervals to fully compress the pads. These
pads are not insulators, they are for heat transfer only and they have a
coating that slightly melts under high temperature. This coating fills all
of the gaps under heat and compression and forms a good thermal path to the
heatsink.

Sears sells a small kit of stripped screw removal tools. These tools bite
into the head of a stripped screw making it easy to remove. Screwdrivers
will ware out and start slipping in the slots. Mt favorite screwdriver is a
magnetic hand tool that holds the bits for power drivers. These bits are
much harder than most standard screwdrivers and can be easily swapped out if
they are worn. The magnet also holds the screw for starting or removing and
the handle of the screwdriver holds several different bits. The handle of
this screwdriver locks or it can ratchet in either direction. Most large
hardware stores carry these screwdrivers.

Don Brown
KD5NDB




----- Original Message -----
From: "Bob Evans" <[hidden email]>
To: <[hidden email]>
Sent: Monday, November 21, 2005 7:40 PM
Subject: [Elecraft] KPA100 stripped final's screw removal

> Hi Folks,
>
>
>
> This may not be a very high tech solution, but it got me out of a
> perceived
> pickle.  I had stripped one of the screws securing the final transistors
> to
> the heat sink in one of my K2/100s.  I was thinking "how the heck am I
> going
> to remove a stripped screw in such a tight space?".  A friend had
> suggested
> super gluing a Phillips screwdriver into the stripped screw.  I tried it
> and
> the super glue didn't hold.  Then I thought I could drill and tap the
> screw
> out, but I couldn't find a tap that was small enough.  What finally worked
> was simply to drill into the center of the screw until the screw head
> detached from the screw shaft.  It took a 5/64" bit.  I had loosened all
> the
> other screws on the board and the board simply lifted away from the heat
> sink when the screw head separated from the shaft.  With the board
> removed,
> the screw shaft could easily be unscrewed from the heat sink and replaced
> with a new screw.  By the way, I turned the KPA100 board screw-head-down
> when I drilled so there wouldn't be much of a chance for metal splinters
> getting into the board.  It worked!
>
>
>
> I have always used a high quality #1 screwdriver when I tightened these
> screws, but it stripped out anyway.  I use my K2/100s exclusively for
> contesting and have been finding I need to re-tighten those screws after
> 20-30 hours of full bore operating (100 watts, lots of CQs).  Maybe a
> Lock-tight type product is needed to keep the screws from backing out
> after
> thermal cycling, but some of you may have some advice whether this should
> be
> done or not.  Anyway, in case you find your final's screw stripped, this
> method worked for me.
>
>
>
> P.S.  I played around in ARRL SS SSB this past weekend.  The K2 is a GREAT
> side band radio too!  I know, I know.I can get ejected from this reflector
> for such heresy.  ;-)
>
>
>
> 73,
>
> Bob K5WA
>
> K2s #4687 and #5119 in SO2R configuration
>
>
>
>
>
> _______________________________________________
> Elecraft mailing list
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> You must be a subscriber to post to the list.
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>
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> Elecraft web page: http://www.elecraft.com
>

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[Bob Nielsen]

On Nov 22, 2005, at 2:01 AM, Bekir Kemal Ataman wrote:

>> I think many "Elekrafters" enjoy CW because the radios (K1, KX1, K2)
>> have such nice characteristics as CW rigs
>
> I can understand people preferring CW because of having CW Rigs and  
> vice
> versa but if it is reaching a point of ejecting/rejecting others  
> for not
> having the same preferences then we have got a problem.
>
>> I think most will welcome you here, and the cw / ssb rivalry is  
>> all in
>> fun (or so it seems to me).
>
> I just hope it is. Otherwise I'd really be disappointed.

Don't worry about it.  There are a few fanatics, but most of us like  
to operate both modes.  Remember that this list also supports the K1  
and KX1, both of which are CW-only, so there may me more messages  
regarding CW than SSB.

>
>> So what antenna(s) are you using with your K2, and what bands are you
>> using it most on?
>
> I have got a 4-band inverted-V on 10, 20, 40 and 80 meters about 20  
> meters
> off the ground. I managed to get SWRs less than 1.2 on all bands after
> struggling for a few weeks on the roof of our apartment block. It  
> seems it
> was worth the trouble.
>
> Although my QTH is blocked by a nearby hill in the East and another  
> nearish
> hill in the North, I have worked quite a few countries with less  
> than 8
> Watts. (My rig does not go above 7.1 to 7.3 Watts, giving a Hi Cur  
> warning.
> I just hope this is normal. Cal Cur is set at 3.5 Ampers)
>

This sounds like there may be a possible problem.  Is it this way on  
all bands?  You should be able to get ~15 watts output from a K2.

> When I could hear the stations early enough, I have managed to  
> contact a
> few Japanese stations, too. When I am little late, my signals get  
> lost in
> the pileup. The European DX Net organized by I2ZGC, Gianni helped  
> me make
> contact with a few North African stations but I could not hear/get  
> heard by
> stations in South Africa nor Indonesia. I sometimes hear a few North
> American stations early in the morning but even then they are very  
> weak
> most of the time.
>
> I work on 40 and 80 meters at night and 20 meters during the day,  
> mostly. I
> could not hear anyone on 10 meters so far. It seems to be very  
> quite in
> this part of the world. Perhaps I just wonder around the wrong  
> frequencies
> or just at the wrong time. I cannot go in the air very often  
> because of
> work load during the week and because of XYL QRM at weekends but I  
> try to
> join contests whenever I can. It is great fun.
>

We are nearing the bottom of the sunspot cycle and propagation  
conditions favor the lower frequencies (10 meters will be useless  
much of the time).  In 4 or 5 years, conditions will be much improved  
on the higher frequencies, so we all need to be patient.  In 2001,  
conditions were much better and I was able to work 100 countries  
running 5 watts into a 30 meter long wire antenna (non-resonant)  
which was only 4 meters above the ground.  These contacts were a  
mixture of CW and SSB and many were on 10 meters.  There is a 10  
meter DX contest which will take place on 10-11 December and that  
will bring out many more operators to that band than you will find  
presently.  I'm sure that your "TA" prefix will be very welcome in  
that contest.

73,
Bob Nielsen, N7XY



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[Don Wilhelm-3]

Bekir,

The power output from your K2 is indeed low and your current draw is higher
than normal.
When this condition exists, the first thing to suspect is the Low Pass
Filters.

Check the inductors for the proper number of turns (count the turns as thay
pass through the center of the core - if the outside is counted, you may be
one turn in error).

Check the capacitors for proper values (look on the schematic to see the
correct values).

73,
Don W3FPR

> -----Original Message-----
>
> Although my QTH is blocked by a nearby hill in the East and
> another nearish
> hill in the North, I have worked quite a few countries with less than 8
> Watts. (My rig does not go above 7.1 to 7.3 Watts, giving a Hi
> Cur warning.
> I just hope this is normal. Cal Cur is set at 3.5 Ampers)
>

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