[CQ-Contest] Re: Kenwood 930 problems?

Martin Ellis jmellis at ihug.co.nz
Fri May 22 09:46:02 EDT 1998

Hello Alan,

I experienced the same problem with a TS930 about 10 years ago.

The main problem area was the final unit board, where the heat from
the output transistors caused movement in the circuit board.
The result was intermittent failure due to lack of connectivity
in the plated thru-holes between the upper and lower surfaces of
the board.   

We observed that in some areas, there was no problem, due to the
presence of components, where the component legs were soldered
on the top and bottom of these thru-holes. The wire legs mad the 
connections secure.  But where there were no component legs,
the broken solder connections occurred.

The solution was to remove the board, using a solder station to
suck out all the old grey/crystallized solder.
We then inserted tinned copper wire into each plated thru-hole, 
and carefully soldered the wire link to both the top surface and
the bottom surfaces. Make sure to use plenty of heat, and get a 
*mushroom* solder joint on each layer.

In my TS930 there were no component failures, and 100% reliability
in the final unit board after this repair.

Hope this is of help.

Martin ZL1ANJ

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