[R-390] Gain drift

[Larry H]

Hi  Dave,  Although you've made very good progress, unfortunately, I'm
thinking you still have a gain problem.  I just tested the stability of
gain on my daily driver and it's what I'd expect.  I set the carrier level
at 40 on a cal signal 3 hours ago and it  held very stable for a long time,
and has drifted slowly down to 39.  This is with the agc hooked up and in
normal cal operation with  8kc bandwidth.  The set had been off for 16
hours.  Wish I had better news.

Regards, Larry

On Sun, Oct 21, 2018 at 3:41 PM dog <agfa at hughes.net> wrote:

> Well I had it on for about 6 hours today and no sign of the gain
> changing all that much. With the AGC jumper disconnected the Carrier
> meter is very sensitive over a small delta rf and with the same input it
> changed from 50 at startup to 25 later on and finally back to about 65.
> Changing the sig gen just a few uV will bring it back to 50. Once the
> AGC is in play that will change. I saw no difference on the plate of
> V504 nor the -9VDC diode load output nor the audible noise from the
> diode load. Tomorrow I'll hook up the RF section and put the RX back in
> order and see what it does from the balanced ant input.
>
> Dave
>
>
> ______________________________________________________________
> R-390 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/r-390
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:R-390 at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>