My K2 #5767 suddenly has quit working. Upon power up today, the freq. readout
is OK, but none of the buttons work and the tuning dial doesn't change freq.
No error messages are seen at powerup.
Anyone have any ideas??
--Mike, W0RSR
Mike,
The symptom of not being able to do anything from the front panel is
usually an indication that it is attempting to transmit as soon as power
is applied. The simple thing that can cause a transmit condition is a
closed key (or PTT). Remove anything from the micophone jack, remove
Mike,
My K2/100 #3255 behaved in exactly the same way some years ago, actually on
two occasions about a year apart. The problem was caused by dirt or
corrosion on the contacts of the socket of the MCU U6 on the Control board.
Pulling and reseating the U6 IC cured the problem on each occasion.
What should the resistances between poles of Q7 Q8 be?
Mac
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I also just noticed that the power output transistors Q7 and Q8 are getting
warm when the power is on. I did not say before but, their is no display
or any other activity on the control board or front panel.
Fred, KC9QQ
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KC9QQ wrote:
I also just noticed that the power output transistors Q7 and Q8 are
getting
warm when the power is on. I did not say before but, their is no display
or any other activity on the control board or front panel.
Fred, KC9QQ
Fred,
In cases like yours, first step is to connect a dummy load to the K2
just in case it is trying to transmit - it is not good to enter transmit
state without a load on the PA transistors. If it is a K2/100, remove
the KPA100 and connect the dummy load to the BNC antenna jack on the
lower
Don Wilhelm-4 wrote:
Fred,
In cases like yours, first step is to connect a dummy load to the K2
just in case it is trying to transmit - it is not good to enter transmit
state without a load on the PA transistors. If it is a K2/100, remove
the KPA100 and connect the dummy load to
KC9QQ wrote:
Don Wilhelm-4 wrote:
Fred,
In cases like yours, first step is to connect a dummy load to the K2
just in case it is trying to transmit - it is not good to enter transmit
state without a load on the PA transistors. If it is a K2/100, remove
the KPA100 and connect
Fred,
Zero volts on both is way better than 8 volts on both - at least the K2
is not trying to transmit.
Check the gates of Q3 and Q4 on the control board. The gate of Q4
should be at 5 volts and the gate of Q3 should be near zero. If that is
true (and only if that is true), short the drain
Fred,
We are 'doubling' with overlapping posts here along with fast paced
responses.
From that brief measurement, I think Q3 is the problem - I base that on
the fact that you measure 8 volts on both D6 and D7. Just remove Q3 to
check that theory. The K2 will receive without Q3 installed,
Kristina,
You will just have to continue measuring things until you discover the
root cause. Did you measure the resistance at the power plug with the
power switch ON? Try the checks below (in order until you find the source).
Measure the resistance to ground from the cathode of D12. You
Many thanks to all who replied to my question. What happened was that
while I was putting T4 on, I overheated the 7-8 winding and it melted
through the insulation of the 3-4 winding, therefore shorting it. So
I just rewound it and it works!
Thanks again!
73,
Kristina KE7LUC
Hi all,
In building my K2 everything has gone perfectly and without a hitch
until I got to the Alignment and Test, Part III. When I try to turn
it on there's an audio pop but nothing on the LCD display and no
relays clicking. It worked just fine before I installed the
transmitter part.
Kristina,
It sounds like you have created a short in the DC power and the
resettable fuse is being activated.
Check all your soldering and the pad placement of the thermal pads for
the PA transistors. Did you check for a short at the collectors of Q7
and Q8 as instructed? If so, what was
Nothing I can see looks to be shorted. And yes I checked the
collectors of Q7 and Q8 and it was 1.6 k ohms, so the problem doesn't
seem to be there. I'll go fiddle with it some more.
Kristina, KE7LUC
On 5/24/07, Don Wilhelm [EMAIL PROTECTED] wrote:
Kristina,
It sounds like you have created a
OK, here's what I've done so far: checked the resistance from the
power plug to ground, the meter read infinite resistance. Also checked
the voltage at the same and got 12 volts. Then I measured the voltage
at the cathode end of D10 and got 12 volts with the power switch on
and off, but at D12 I
Hi everyone and thanks everyone for answering to my dead K2 on 3,5 and
7,0
the K2 is alive and the owner is reading the op.manual very very closley !
73 de Rolf
SM2MZC
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