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Blown fuse KPA100

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Hank Kryger

Blown fuse KPA100

Hi to the group

I am in the final phases of finishing my KPA100, version "C" with
upgrade kit for "D".version. Manual page 46 (version C manual)
External Amplifier Keying Test (PA KEY),

right hand column, step 2, "measure ground to Q9 tab. Result as
noted in the manual.

right hand column step 3, Hold TUNE. When I do this the DMM reads 3.2
Ohm, as noted in the manual, but as soon as the reading starts, when
holding TUNE, the Ohm reading starts to increase, at a steady pace. At
around 8.9 or 9.2 Ohm the fuse in my power supply, 20 Amps, went,
replaced it with a 25 Amps, did test again and this time the 20 Amp
fuse in the power cord went,

There was no smoke or smell at the time this happened. I did have my
50 Ohms dummy Load attached to the antenna as a precaution.

Any help would be appreciated. Thanks, Hank WA9QJH

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Don Wilhelm-3

Re: Blown fuse KPA100

Hank,

First thing is an instruction that you apparently skipped - put the K2
into CW TEST mode before doing that test. You may have another problem,
but the amp should not draw significant current in CW TEST.

Second thing (but check it first) is the KPA100 bias. Be certain the
bias pot is set fully counter-clockwise until you get to the step for
adjusting that pot.

You do have a 0.22 uF cap at C31 do you not?

73,
Don W3FPR

Hank Kryger wrote:

> Hi to the group
>
> I am in the final phases of finishing my KPA100, version "C" with
> upgrade kit for "D".version. Manual page 46 (version C manual)
> External Amplifier Keying Test (PA KEY),
>
> right hand column, step 2, "measure ground to Q9 tab. Result as
> noted in the manual.
>
> right hand column step 3, Hold TUNE. When I do this the DMM reads 3.2
> Ohm, as noted in the manual, but as soon as the reading starts, when
> holding TUNE, the Ohm reading starts to increase, at a steady pace. At
> around 8.9 or 9.2 Ohm the fuse in my power supply, 20 Amps, went,
> replaced it with a 25 Amps, did test again and this time the 20 Amp fuse
> in the power cord went,
>
> There was no smoke or smell at the time this happened. I did have my
> 50 Ohms dummy Load attached to the antenna as a precaution.
>
> Any help would be appreciated. Thanks, Hank WA9QJH

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KJ3D-2

KAT-100

Good Morning Group,

I'm beginning the KPA100 and KAT100 build this weekend and have some
questions.

True or False: I must run two power lines from my Astron 35, one to the
KPA100 and another to the KAT100.

True or False: I MAY connect a secondary power supply (turned off) to the
barrel connector on the K2 in case the Astron fails.

True or False: If the Astron fails, the K2 will go into bypass mode and
continue to work at QRP levels if I then turn on the secondary power supply.

REAL QUESTION: If the K2 is running in the bypass mode, will the
KAT100 then take power from the secondary power supply?

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KJ3D-2

RE: KAT-100

How tacky -

I forgot to sign my own question...

Thanks es 73,

Tom, KJ3D

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of KJ3D
Sent: Saturday, April 21, 2007 7:46 AM
To: [hidden email]
Subject: [Elecraft] KAT-100

Good Morning Group,

I'm beginning the KPA100 and KAT100 build this weekend and have some
questions.

True or False: I must run two power lines from my Astron 35, one to the
KPA100 and another to the KAT100.

True or False: I MAY connect a secondary power supply (turned off) to the
barrel connector on the K2 in case the Astron fails.

True or False: If the Astron fails, the K2 will go into bypass mode and
continue to work at QRP levels if I then turn on the secondary power supply.

REAL QUESTION: If the K2 is running in the bypass mode, will the
KAT100 then take power from the secondary power supply?

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Don Wilhelm-3

Re: KAT-100

In reply to this post by KJ3D-2

TRUE to all your T/F questions.

To answer the REAL question, yes the KPA100 will go into bypass if power
is removed from it. The KAT100 does present a problem if it is powered
from the same supply as the KPA100 and that supply fails or is switched
off because the KAT100 does not use latching relays - with power off it
will revert to all capacitors disconnected and all inductors bypassed
and ANT 1 will be selected. In other words, the K2 output will be
connected to whatever SWR your antenna presents without the tuner in-line.

The KAT100 and base K2 SHOULD continue to work seamlessly at lower power
if you power them both from the low current power supply, but I have not
really tried that scenario.

73,
Don W3FPR

KJ3D wrote:

> Good Morning Group,
>
> I'm beginning the KPA100 and KAT100 build this weekend and have some
> questions.
>
> True or False: I must run two power lines from my Astron 35, one to the
> KPA100 and another to the KAT100.
>
> True or False: I MAY connect a secondary power supply (turned off) to the
> barrel connector on the K2 in case the Astron fails.
>
> True or False: If the Astron fails, the K2 will go into bypass mode and
> continue to work at QRP levels if I then turn on the secondary power supply.
>
> REAL QUESTION: If the K2 is running in the bypass mode, will the
> KAT100 then take power from the secondary power supply?
>
>
> _______________________________________________
> 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
>

KJ3D-2

RE: KAT-100

Hi Don and Jim,

Thanks for taking the time to respond.

The KPA100 will be internal and the KAT100 will be in an EC1.

After re-reading the manuals for the KPA and KAT 100's, maybe this isn't so
hard.

I think that I can connect my secondary supply directly to the K2 and then
power the KAT100 via a switch to select either the main or secondary
supplies while main/secondary power to the K2 would be automatically
switched from main to secondary if the Astron fails.

Does this sound reasonable or am I missing something else?

Thanks,

Tom

-----Original Message-----
From: Don Wilhelm [mailto:[hidden email]]
Sent: Saturday, April 21, 2007 8:05 AM
To: KJ3D
Cc: [hidden email]
Subject: Re: [Elecraft] KAT-100

TRUE to all your T/F questions.

To answer the REAL question, yes the KPA100 will go into bypass if power is
removed from it. The KAT100 does present a problem if it is powered from
the same supply as the KPA100 and that supply fails or is switched off
because the KAT100 does not use latching relays - with power off it will
revert to all capacitors disconnected and all inductors bypassed and ANT 1
will be selected. In other words, the K2 output will be connected to
whatever SWR your antenna presents without the tuner in-line.

The KAT100 and base K2 SHOULD continue to work seamlessly at lower power if
you power them both from the low current power supply, but I have not really
tried that scenario.

73,
Don W3FPR

KJ3D wrote:

> Good Morning Group,
>
> I'm beginning the KPA100 and KAT100 build this weekend and have some
> questions.
>
> True or False: I must run two power lines from my Astron 35, one to
> the KPA100 and another to the KAT100.
>
> True or False: I MAY connect a secondary power supply (turned off) to
> the barrel connector on the K2 in case the Astron fails.
>
> True or False: If the Astron fails, the K2 will go into bypass mode
> and continue to work at QRP levels if I then turn on the secondary power

supply.

>
> REAL QUESTION: If the K2 is running in the bypass mode, will the
> KAT100 then take power from the secondary power supply?
>
>
> _______________________________________________
> 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
>

Don Wilhelm-3

Re: KAT-100

Tom,

Would it not be easier to simply connect the KAT100 permanently to the
secondary power supply?

If you have the secondary supply always connected to the K2 (and powered
on) for backup QRP operation, then I don't understand why you would want
to provide a switch in the KAT100 power line. There is no real
advantage to powering the KAT100 from the same supply that powers the
KPA100. You would have to be certain the secondary supply is powered on
first, but that should be easy enough to accomplish.

Or perhaps you are envisioning some other operating situation that has
not occurred to me yet.

73,
Don W3FPR

KJ3D wrote:

> Hi Don and Jim,
>
> Thanks for taking the time to respond.
>
> The KPA100 will be internal and the KAT100 will be in an EC1.
>
> After re-reading the manuals for the KPA and KAT 100's, maybe this isn't so
> hard.
>
> I think that I can connect my secondary supply directly to the K2 and then
> power the KAT100 via a switch to select either the main or secondary
> supplies while main/secondary power to the K2 would be automatically
> switched from main to secondary if the Astron fails.
>
> Does this sound reasonable or am I missing something else?
>
> Thanks,
>
> Tom
>

KJ3D-2

KPA100 parts issues

In reply to this post by KJ3D-2

Good Evening,

Before contacting Elecraft, perhaps someone is currently building a KPA100
or has recent experience who could answer some questions.

I have completed the parts inventory for the KPA100 and have a three
unresolved issues.

1. Inventory says RFC3 and 11 have tan bodys. I have two of the same value
only with green bodies. Is this OK?

2. Inventory says C64 and C79: .0047 (472) .4 LS mono 250 V or above. I
have 2 squarish blue things identified as 4N7 J250 TD with .4 LS. I cannot
identify them as being anything else. Ya think they're C64 and C79?

3. Errata says C2A and C6D: 1200 pf (6122) 630 Poly. I have a pair of
brown caps labeled P122J 630 F that I cannot associate with anything else.
Again, are these C2A and C6D?

Thanks,

Tom, [hidden email]

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Don Wilhelm-3

Re: KPA100 parts issues

Tom,

You point out some of the fallacies in attempts to identify components.
As far as the inductors are concerned, the only thing that matters is
the color code stripes. The fact that they had tan bodies when the
manual was written has been superseded by either a change in vendor or
the whim of the manufacturer. I believe the current bodies may be
green. Even if the body color is yellow, white, tan, green, blue or any
other color, if the stripes are brown, black, brown, that would indicate
a 100 uH inductor.

Capacitors are similar, but can be more complex. The significant
identifiers are the value and the rated voltage. In the case of the
1200 pf capacitors, that value would be indicated by '122' which means
two significant digits of '12' followed by 2 zeros - so 122 equals 1200
pf. the other marking of '630' should indicate the voltage rating.
While capacitors may vary a lot in the particular markings that may be
used, it is always a good idea to become familiar with the marking
conventions that are in current practice. The Component Data section of
the ARRL Handbook has a good writeup on capacitor markings that every
builder/ham should be familiar with.

Now, the 4N7 marking - the 'N' indicates 'nanofarad', which is likely
fully understood by European hams, but not so certain by US hams who are
more accustomed the microfarads and picofarads. Nanofarads is 10^-9 and
therefore 1 NF is 1000 pf or .001 uF. An easy way to convert is to
slide the decimal point (represented on the capacitor by the position of
the 'N') by 3 places. So a capacitor marked 4N7 is 4.7 Nanofarads, or
4700 pF, or .0047 uF.

OK, so much for the tutorial - all your assumptions are correct.

73,
Don W3FPR

KJ3D wrote:

> Good Evening,
>
> Before contacting Elecraft, perhaps someone is currently building a KPA100
> or has recent experience who could answer some questions.
>
> I have completed the parts inventory for the KPA100 and have a three
> unresolved issues.
>
> 1. Inventory says RFC3 and 11 have tan bodys. I have two of the same value
> only with green bodies. Is this OK?
>
> 2. Inventory says C64 and C79: .0047 (472) .4 LS mono 250 V or above. I
> have 2 squarish blue things identified as 4N7 J250 TD with .4 LS. I cannot
> identify them as being anything else. Ya think they're C64 and C79?
>
> 3. Errata says C2A and C6D: 1200 pf (6122) 630 Poly. I have a pair of
> brown caps labeled P122J 630 F that I cannot associate with anything else.
> Again, are these C2A and C6D?
>
> Thanks,
>
> Tom, [hidden email]