[Elecraft] PA Transistors Maintenance in K2

[Ron D'Eau Claire]

When writing and validating the kit assembly procedures, I restrict myself
only to the basic hand tools recommended by the design engineers. The
objective is to avoid customers having to go out and buy additional tools
that are not really needed. If I find that I cannot do a particular step
with those tools I bring it up to Wayne and the other engineers who decide
on an alternative. Sometimes that is to require a new tool. For example, we
went through that over adding the requirement for a temperature-controlled,
ESD-safe soldering iron some years back. The K2 and other early kits had no
such requirement but as more sensitive components were used, Wayne specified
that we add it to the tools requirement.

On the other hand, there are times we have specifically said NOT to use a
special tool. A while back we had a lot of damaged parts because builders
were using electric screwdrivers that had no torque control or which had the
torque set too high, so Wayne had me say NOT to use them, preferring hand
pressure instead.

Actually we do provide torque spec's in one case; the mounting nut for the
transformer in the KPA500. That nut must work against a Belleville washer
that acts as a spring. The objective is to apply the right pressure to the
washer (55 inch pounds) without permanently deforming it. But, even in that
case, the engineers came up with a workable alternative to avoid builders
having to go out and buy a torque wrench. 

73, Ron AC7AC


-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of David Woolley
Sent: Sunday, October 29, 2017 6:04 AM
To: elecraft at mailman.qth.net
Subject: Re: [Elecraft] PA Transistors Maintenance in K2

As far as I can tell, no torque settings are given for any of the fasteners,
wouldn't it be an idea to provide those, for people who do have suitable
tools.  Generally there are just warnings not to over-tighten.

On 28/10/17 20:24, Mel Farrer wrote:
>   If the people at Elecraft have done their job and mounted the transistor
properly with the correct torque on the mounting hardware procedure, no
additional maintainance is required.

--
David Woolley
K2 06123