[R-390] C-103

[David Wise]

Two leads - positive, one lead - negative.
This is not a critical cap.  It parallels the
RF GAIN control to keep wiper noise from blowing
out your ears as you rotate it.  With RF GAIN at
max, there will be no voltage across it.

You are fighting with both hands tied behind
your back if you don't have a service manual.
Go to www.r-390a.net and get the latest revision
of the Y2K manual.  C103 is in Figure 6-35 on
page 6-84, and Figure 5-22 on page 5-52.

73,
Dave Wise

> -----Original Message-----
> From: r-390-bounces at mailman.qth.net
> [mailto:r-390-bounces at mailman.qth.net]On Behalf Of Carole White-Connor
> Sent: Thursday, October 26, 2006 7:52 PM
> To: R-390 at mailman.qth.net
> Subject: [R-390] C-103
> 
> 
> Another newbie question:
> 
> I was looking at C-103, the 50 mfd/50V electrolytic on the 
> back wall of the
> receiver. Here are my questions:
> 
> 1. How can I determine the polarity of that cap? Is negative 
> the lead with one
> wire attached or two attached?
> 
> 2. What does C-103 do? I did not find it in a quick perusal 
> of the schematic.
> 
> 3. I measured mine. I did not detect any voltage on either 
> prong. Each prong
> seemed to measure continuity to ground. That has me concerned.
> 
> As always, thanks!
> 
> 
> Joe Connor
>