Fixing the Autek VA1 (an RF construction lesson?)

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Fixing the Autek VA1 (an RF construction lesson?)

Robert Cochrane
Apologies if this thread has gone on too long.

Don Brown has pointed owners in the right direction if they have a poor
quality Autek instrument.  Mine came from the bottom of the low quality pit
so it may be worth setting out the fix in a bit more detail.  It also
taught me a lot about RF physical & mechanical construction needs.

Most of the problems were caused by a combination of poor solder joints and
badly secured switches and tuning caps, pots etc.  I think the very
unstable readings were mainly due to poor mechanical stability resulting in
varying stray capacities.

All this is at owners risk of course, but it cost me less hassle than going
back to Autek from the UK.  Nothing harder than fixing a K2.  Just take it
slowly.

Remove the battery
Remove the two tuning knobs
Turn over, and unscrew the two case screws in deep recesses
Ease the two case halves apart GENTLY - there are two boards with a
multi-pin connector.
Remove the two (or three!) retaining screws on the upper board with the LCD
display.
Avert your eyes from the interior of the top of the case, which appeared to
have been carved to fit by a ten year old using a hot soldering
iron.  Ugly, but not the problem.
Don't remove the lower board unless the basic fix does not solve the
problems.  More difficult as it is connected to the output socket and my
bottom board was much better than the top one.
Check the top of the bottom board for poor joints and also unsoldered
component lugs, using an eye glass.
Check both sides of the top board the same way.
With a small tip on a temperature controlled iron, a wrist strap and GREAT
CARE, resolder any poor joints.
Solder any unsoldered locating lugs on pots, switches and variable caps
etc  Mine had lots of these - some switches were hanging on by a
corner.  Be careful near the LCD.
Check again, particularly for solder bridges etc and clean up with solder
braid.
Reassemble (reverse of disassembly).

Tighten all screws carefully but firmly by hand to give maximum mechanical
stability (the case is not really stiff enough).

Such a shame that such a neat piece of kit was so badly constructed.

Wayne - as others have suggested, is there a niche for an Elecraft
miniature 0-30 MHz amateur bands aerial analyzer with good mechanical
design, more digits and perhaps a few extras like a minimum SWR frequency
search and value?  Must give signed reactance, of course.

Could be a kit, but I guess it would need a board with some SMD chips
pre-soldered.

Rob M0RAC




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SMD hand soldering [was Fixing the Autek VA1 (an RF construction lesson?)]

Kevin Rock
There is really no need to have SMDs pre-soldered.  The learning curve for
hand soldering them is pretty quick and once mastered is rather fun.  No
drinking coffee while you're building though ;)
    73,
       Kevin.  KD5ONS

On Tue, 19 Apr 2005 08:32:40 +0100, Robert Cochrane
<[hidden email]> wrote:
>
> Could be a kit, but I guess it would need a board with some SMD chips
> pre-soldered.
>
> Rob M0RAC


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