[Elecraft] K3 - 100 watt amp dead?

[George Fremin III]

On Tue, Nov 29, 2022 at 06:19:45PM +0000, Michael Carter wrote:

> The original 100 watt PA (KPA3) used RF BJTs as the finals,
> whereas the KPA3A used RF MOSFETs (LDMOS).

I took it apart a few weeks ago.  I did not note what transistors are
in it.  I will be taking it apart again when I have time in the next
week or so.

It all looked good.  I can detect no burned smell of any kind nor did
I see anything obvious.  I did clean things up and put it back
together.

It does have the gold pin update. 

> similar problem revealed the fault to be in one
> of the RF chokes (the red toroids on the 100 watt
> PA board) that feed DC to the PIN diode switches.
> The problem was a broken wire on one RF choke.

I did look at these but in retrospect I did not look closely at the
wires on each.  I will do that when I take it apart again.

I do see it drawing current in transmit and that seemed to go up as I
turned up the power control.  I did not note the amount of current
shown on the K3 display but I will look at this further in a few days.

Thanks for all the good advice so far - once I am back with the radio
I will dig into it a bit more.

-- 
George Fremin III - K5TR
geoiii at kkn.net
http://www.kkn.net/~k5tr