[CQ-Contest] TS940S trouble

[Zack Widup]

On Thu, 9 Aug 2001, Bob Wolbert wrote:

> 
> Wim,
> 
> When the display on the TS-940 shows all dots, it is telling you the PLL
> has become unlocked. Probably one of the inductor cores on the PLL board
> must be adjusted. 
> 
> I recommend performing the PLL alignment described in the service manual.
> 
> 73 de Bob, K6XX
> 


I don't own a TS-940 but I understand this problem is similar to the one
the TS-440 has.  The PLL board was covered with an adhesive cement to keep
the components from falling off the board.  Why they do this I don't know;
I've never had any components I've soldered correctly fall off a homebrew
board!

This glue eventually absorbs humidity and breaks down and begins to become
conductive.  It is a light tan color which becomes darker as it
deteriorates.  Before I cleaned up my TS-440, the PLL's would come
unlocked particularly in hot, humid weather.  I finally took the PLL board
out and removed ALL the affected (glued) components and removed the glue
from everything on the board.  It was a long, slow, tedious job but I
haven't had the problem since.

73, Zack W9SZ


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