[Kenwood] TS-430 PLL Problem...

[Steve Kent]

Joe:

I just posted he schematic to my web space.  Check out:
http://home.netcom.com/~skent/hamradio/TS430/TS-430s_ControlUnit.pdf

Pin 8 is the phase detect out pin on the PLL IC, driving a LPF, and 
ultimately the varactor diode for VCO2.

Oh, yes, I have seen those plated thru holes cause problems, especially 
around leaky electrolytics!

Fortunately (or unfortunately) this board is a single-sided board so I 
don't have to sweat that!

73,
Steve - KW5CQ

Hi Steve.

Interesting problem. I've had experince with PLLs over the years, 
though not necessarily with the TS-430's (although I did own one for 
awhile). Anyway, let me throw in my two cents' worth.

One time I had to troubleshoot a Drake FS-4 synthesizer. Its job was 
to generate a signal in 500 kHz increments. However, it was doing it 
only in 1000 kHz increments. Turned out all the components were fine, 
but a plated-thru via hole was not conducting from one side of the 
PCB to the other! Reflowing the solder joint and shoving a strand of 
wire through the hole fixed it. Maybe your PLL is sufferiing a 
similar problem.

What is IC8 Pin 8? Is it a PLL lock detect signal, or is it a divider 
programming input?

Wish I had a schematic of the '430; I'd try to help you try to figure 
out this puzzler.

73,
Joe K9LY


At 11:47 AM -0600 2/12/08, Steve Kent wrote:
>Hi Ken:
>
>Thanks for the reply....
>
>I looked at the band select data lines and unfortunately they check 
>out ok per the service manual.  I believe that my problem is 
>somewhere in the PLL2 loop. IC8 Pin 8 goes dead, to 0V when the 
>radio is in 'the dead zone'. PLL3 appears to be tracking as it 
>should.
>
>I wish I had another radio to compare it to!
>
>Regards & 73,
>Steve Kent
>KW5CQ
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