[Kenwood] TS-940S PLL Trouble

[Bill Smith]

I have a TS-940 with warbley audio when it is cold.  The set also may blank
the display (shows all dots), but only briefly, and only when it is first
turned on.  Both are intermittent.  As it warms up (usually less than two
minutes), both symptoms apparently disappear.

It was most noticable last winter, presumably when the air was cooler and
humid.  Although the previous owner stated he adjusted the PLL circuitry (he
didn't specify which PLL), IHMO, the rosin residue should be removed from
the bottom PC board before any further adjustment.

Several other problems disappeared when the regulator board was resoldered.
Haven't attempted to chase the instability yet.  Do you have any
suggestions?

73 de Bill, AB6MT
billsmith at ispwest.com


----- Original Message ----- 
From: Clif Holland
To: Michael Tope ; kenwood at mailman.qth.net
Sent: Thursday, June 03, 2004 7:54 AM
Subject: Re: [Kenwood] TS-940S PLL Trouble


Before it goes off is the rx audio warbley or distorted??

Clif Holland, KA5IPF
AVVid
Authorized Kenwood and Icom Service Center
816 W Shady Grove Rd
Irving, TX 75060

www.avvid.com

1-800-214-5779
972-870-0630 (Local)
----- Original Message ----- 
From: "Michael Tope" <W4EF at dellroy.com>
To: <kenwood at mailman.qth.net>
Sent: Thursday, June 03, 2004 2:02 AM
Subject: [Kenwood] TS-940S PLL Trouble


> Hi All,
>
> I have a late model TS-940S (S/N 904xxxx) which has a
> problem with frequency display blanking (and corresponding
> receive audio cutout) which if I understand correctly is an
> indication that one of the rig's PLLs is unlocking. Originally,
> when the problem occured, the frequency display would blink
> alternating between all dots and the displayed frequency.
> Thinking I had a faulty ROM socket, I went down that path a
> soldered IC2 directly to the digital board. This didn't cure the
> problem, it just changed it. Now when the receiver cuts out,
> the display goes to all dots and just stays that way (as opposed
> to alternating between dots and alphanumeric). The problem
> comes and goes and doesn't appear to correlate with any
> external stimulus. I poked around the digital board and the
> PLL unit and couldn't find any obvious loose connection or
> mechanically sensitive points which would induce the failure
> when stimulated. Wiggling and twisting the chassis with the
> covers off (to put a little twist in the PC boards) doesn't seem
> to do anything either.
>
> Any suggestions for what might be causing this? The radio
> works fine otherwise, but isn't much good for anything since it
> can cut out without warning.
>
> Thanks,
>
> Mike, W4EF......................................................
>
>
>
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