[Elecraft] K2 Q7 Collector To GND Resistance Reading

[W3FPR - Don Wilhelm]

Gary,

You have a short (or at least a very low resistance) to ground somewhere in 
the PA collector circuit or on the +12 volt line.

The easiest first step in isolating it is to remove the heat sink.  The tabs 
on the PA transistors are connected to the collector, and the thermal pads 
are supposed to act as an insulator as well as a heat transfer medium.  It 
is quite possible that a bit of metal is lodged in the thermal pads, and the 
best way to check that is to remove the heat sink (rear panel).

If the short remains after removing the heat sink, look very carefully at 
the soldering in the PA area - it only takes a sliver of solder splash to 
create a short.

73,
Don W3FPR

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

> In running the final Resistance Checks on p. 71 of the K2 manual, I only 
> get 1.7 ohms at the Q7 collector. The manual says I should get >500 ohms. 
> When I study the schematic, I can't see where the >500 ohms is supposed to 
> come from since Q3 is connected across Q7 and Q8 collectors and the 12V 
> line.
>
>