[ARC5] T-19 Update

[Mark K3MSB]

Yes, I am keying via the cathodes.

I did measure across R74 as you recommend, and my measurements were about
the same.  The value of R64 is 15.9K;  up a bit but not enough to account
for what I'm seeing.

I'm going to see if I have any spare tubes to swap tonight.

Mark K3MSB

On Mon, Dec 17, 2012 at 9:16 PM, Neil <neilb at ihug.co.nz> wrote:

> > The proper way to check the level of drive is to measure the DC volts
> > across R74, the 15K grid bias resistor. You can measure that with the
> > 1625's keyed or unkeyed and it should hardly vary from one to the other.
>
> I wrote the above but didn't make clear that I was referring to keying of
> the 550VDC supply to the 1625's by contacts in the modulator, as was
> done in the original configuration.
> If the 1625's are keyed in the cathode leads (as many hams prefer to do),
> the grid current will fall to zero each time the contacts open.
>
> 73 de Neil ZL1ANM
> ______________________________________________________________
> ARC5 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/arc5
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:ARC5 at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>