[Elecraft] That Little battery in the K2 # 01264

[Ron D'Eau Claire]

On the K2 the only such battery in the K2 is the real-time clock battery.
The clock is part of the DSP option. 

That should NOT cause distorted audio, of course, if it was just resting on
the speaker magnet (and not touching the paper speaker cone). 

I believe Andrew is thinking of the speaker mount in the K2/10 when he
warned about not over-tightening the speaker screws. That is very critical,
but the speaker mount in the KPA100 doesn't have that issue. 

However, starting with the bad news first, it is quite possible that the
bump that dislodged the battery damaged the speaker by bending its frame.
That speaker has a fairly soft metal frame holding a fairly heavy magnet.
I've seen an number of instances (including with my own K2) where just the
bumping and banging of the speaker alone in its box before the radio was
assembled was enough to deform the frame and cause the voice coil to run
against the magnet and cause a buzz or fuzzy audio.

It's that tendency of the frame to bend that caused the issue Andrew wrote
about in the QRP K2 when it was installed and the screws tightened too much.


Replacing the speaker, or straightening the frame (which is easily done in
most cases if it's accessible) require dismantling the whole KPA100 again.
One speaker mounting screw is buried under the KPA100 pcb. 

So let's consider less extreme possibilities first: 

You can see three of the mounting screws with the side cover removed. Are
they in place and does the speaker seem secure and solid against the heat
sink where it's mounted?

Is anything touching the cone that you can see? Sometimes the little leads
running from the speaker terminal strip into the voice coil can get pressed
so they are just touching the cone and will cause a buzz when the speaker
cone tries to move to reproduce sound. If in doubt, pull then away from the
cone slightly. Be very careful reaching in with a thin tool to get the
inside wire that you don't puncture the cone. You should be able to see the
inner wire in the thin gap between the magnet and the white terminal strip.
The cone not really fragile, but a sharp tool can puncture it easily enough.


If nothing is touching the cone from the bottom, then the speaker will have
to come out. 

Ron AC7AC





-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Phil Townsend
Sent: Friday, December 24, 2010 10:29 AM
Cc: Elecraft Reflector
Subject: [Elecraft] That Little battery in the K2 # 01264

I just got my K2 back from Don  and Allen... Thank you...Both.

But I might have a problem. 
When I hooked up the rig and listened to 40m and 20m both on SSB the sound
coming from the speaker was raspy and distorted. Also it sounded very thin.
So I plugged in my AKG 701 headphones...Yes, that was better.
But I of course wanted to get to the bottom of the problem...so I unscrewed
the left side next to the speaker.
Aha! that little flat battery had slipped out of it's holder and was resting
on the speaker magnet shield.
(No doubt it popped loose in shipping)

So my question...What does that battery do?
Would it have anything to do with the raspy audio?
Can I just put it back in and be good to go?

Or am I simply screwed.

K2# 01264
Now upgraded with 100 watt amp etc etc.

Thank You all for help.

Phil
Santa Fe

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