relay problem on SB-401

[Stewart D. Lyon]

The design of the relay amplifier is a tad marginal on the SB-401. I changed
the circuitry of a couple to that like the SB-101 (et al). I don't have the
schematic in front of me but it involves removing the cathode resistor of
the relay driver and replacing it with a 15 V zener diode.  A side effect is
the changing of the time-constant of the "VOX delay" circuitry which can be
fixed by adding a 0.2 uf across the existing time delay capacitor. All this
can be done on the back side of the board where no one can see it.

If you want to pursue this, I can dig my schematics out and give you a
better description.

73, Stu W6CUX

----- Original Message -----
From: "Glenn A. Hartmann W2Tpe" <W2TPE94 at AOL.COM>
To: <HEATH at LISTSERV.TEMPE.GOV>
Sent: Monday, October 02, 2000 2:51 PM
Subject: relay problem on SB-401


> group,
>   being just a tad electronically challenged, i'm appealing to you for
> direction with this problem. while trying to tune up the 401 last night i
> could not get the relay(s) to react, either in the tune position or in key
> down. i pulled the chassis out of the case today and found that, with a
> minimal amount of pressure on the top of the RL-1 relay, it would react to
> the key. the only thing i have tried doing is to play with the anti-vox
adj.
> to no avail. i have the manual, i'm just hoping someone can point me in
the
> right direction. thanks to all, keep up the good work.
> 73 de glenn - w2tpe
>

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