[Central-Electronics] Slicer PS-1 help

[K6JEK]

George,

I agree.   In fact, I have now discovered that C8 is very leaky, more  
of a resistor than a capacitor.   The schematic shows all the caps in  
the PS-1 as variable caps but they are, in fact, mica caps paralleled  
by trimmers.  C8 is a goner.

Some of my Collins collector friends have told me that the old rule  
off thumb that paper caps are probably bad and micas never are is no  
longer true.   This is the second bad mica cap I've found in this unit.

I'll let you know if replacing this cap made the difference.

Jon, K6JEK

On Aug 30, 2007, at 7:40 PM, George Maier wrote:

> Very nice tip, Jim.
> Jon: before you get to tweaking, you should take the time to check the
> resistor values, and make sure that the fixed caps are not open or  
> shorted.
> Not too much chance of them being leaky, but you never know.
> 73 & good luck,
> George - W1LSB
>
>
> -----Original Message-----
> From: central-electronics-bounces at mailman.qth.net
> [mailto:central-electronics-bounces at mailman.qth.net] On Behalf Of Jim
> Candela
> Sent: Wednesday, August 29, 2007 9:45 PM
> To: 'K6JEK'; central-electronics at mailman.qth.net
> Subject: RE: [Central-Electronics] Slicer PS-1 help
>
>
>
> -----Original Message-----
> From: central-electronics-bounces at mailman.qth.net
> [mailto:central-electronics-bounces at mailman.qth.net] On Behalf Of  
> K6JEK
>
> Do any of you have any experience servicing the PS-1 in the sideband
> slicer?
> It sure would be great if one of you knows the procedure for
> adjusting those trimmers.
>
> Thanks,
>
> Jon, K6JEK
>
>
> Jon,
>
>  If this PS-1 is the same as in a CE 20A, then you drive it with a  
> sine
> wave around 1 KHZ and look for equal amplitude outputs that are 90
> degrees in phase from each other (1/4 wave) . If you look at the two
> outputs on an oscilloscope ( X:Y setup) you should see a near perfect
> circle. The 90 degree phase shift and amplitude balance should remain
> pretty much constant from 300 - 3000 hz.
>
> I have set up a 20a PS-1 before this way. It's not magic.
>
> See the following link, set both fx and fy to 10hz and the initial  
> phase
> to 90 degrees.
>
> http://www.ngsir.netfirms.com/englishhtm/Lissajous.htm
>
>
> Regards,
> Jim
> WD5JKO
>
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