[Elecraft] K3 low Power

[Dick]

Martin,

I had the same problem on this end, and I can guarantee your problem is on
the LPF board (bad MOS FET).  If you key up with no power out, and any of
the three on the LPR board are cool, they are bad.  One is the driver, and
the two are the finals to drive the 100W amp.

Hopefully, the two "cool" ones are the RD15SHVF1.  It is best you replace
the two finals at the same time.

They are easy to replace, and it can be done without removing the LPF board
(but I found it easier to do it with the board out). 

Dick K8ZTT

-----Original Message-----
From: Elecraft [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Martin
Sent: Monday, May 12, 2014 3:53 PM
To: elecraft
Subject: [Elecraft] K3 low Power

Elecrafters,
a little while ago i had an issue with loss of rf-power.
I thought i had found the problem. I hadn't.

Symptom now:
Power out only about 3 Watts.

I removed the 100W-PA, changed the Menue to 'not inst'.

With TUN PWR set to 12W i can achieve about 2.5W .

Only 1 of the 3 Transistors on the low-Power PA gets warm during (short)
transmissions with the bottom cover removed.

There are 2 RD15HVF1 and 1 RD06HHF1. How can i check if a transistor is
defective?

Any help welcome.


I think the 100W PA is ok. Well , i hope .

-- 

Ohne CW ist es nur CB..

73, Martin DM4iM
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