SB 200 Upgrade

[Stewart Lyon]

John,
A couple of hints on Softkey and the ps board. Instead of drilling for a
mounting screw, use two 1"x1" 3M mounting pads (one on top of the other)
to mount the PCB. They will stick forever and you don't have to worry
about drilling into something important -- like a tube. Using two will
assure that the wire ends won't poke through and ground out.

Replace the front panel 100K pot with one that has an ON/OFF switch and
route the keying line through this switch on its way to the back panel
jack. This way you can put the -200 on standby without switching the
power off. You can also accomplish the same thing by an external switch
in the keying line but the pot way is handier -- if you can find a pot
with on switch on it. I think the pot has a linear taper.

If you are going to use the amp with a transistorized transceiver, the
AGC output level is probably too high. There was an article in the now
defunct "Heathkit Technical Journal" on installing a pot to adjust the
AGC to suit the driver. All my rigs are tube-types so I never tried it.

When you replace the power supply board, don't discard the old board.
Those capacitors are the same as used in the HP23 power supply and may be
still have some history left.

The SB-200 *is* an excellent amplifier and even better with the Harbach
additions. Good luck with yours.

73, Stu - W6CUX
Winnetka, CA
ARRL Life Member

On Fri, 15 Oct 1999 14:39:24 EDT John Barkow <KD6PT at AOL.COM> writes:
>Hi Gang:  Still in the throws of working  on the  SB 200. ......

> I received the Harbach pwr supply and soft key but haven't installed
them as yet.
>Next, are there any other mods or component upgrades
>that are recommended. Want to get it all done now as there are manly
more  good
>years in this excellent amp.
>Thanks to all,  John kd6pt.

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