[ARC5] T-22 Woes

[Mark K3MSB]

Hi Guys --

Used the scope as Ian suggested.  I had it out today and was probing with a
pickup loop.  I then remembered that I used a loop when I was working on my
5100 and it provided not so clean waveforms when the transmitter was OK.
So, used the coupling cap....

I used a 33 pf coupling capacitor as it was the lowest I had with a 1 KV
rating.

Measured at the output of the transmitter (external antenna terminal)
before the matching capacitor and 4:1 UNUN:

If using a 67 pf matching cap:  Waveform is clean and about 12V P-P
if using a 100 pf matching cap:  Waveform is clean and about 10V P-P

The outputs on the other side of the matching caps are really, really small
(remember I found the 67 pF cap works great with my other T-22).

The roller inductor has no effect throughout it's entire range.
The antenna coupler has no effect throughout it's entire range.

I listened to my signal on the 756 and it sounds a bit rough, but not to
bad otherwise.

Well guys, I've had fun today working on the radios and I'm bushed so I
think it's time to call it a night.

BTW, to clarify a previous email,  I and now (I had mistyped "not") using
the keying and voltage divider as per Dave S. and the manual.

73 Mark K3MSB






On Tue, Jun 11, 2013 at 6:55 PM, David Stinson <arc5 at ix.netcom.com> wrote:

>
> I'm betting your tank is not resonant due to Hi-Z contacts.
> This is a very common problem.
> Check the screws that mount the variable caps,
> tank coil and roller coil, especially those that are supposed
> to provide grounds.
>
> Ground one end of your ohmmeter.
> Probe the top tank coil contact.
> It should read grounded.
> If it does not, check the connection at the bottom of the tank coil.
>
> Next,  open the bottom of the rig.
> Gently probe the stator plates of the two front-most variable caps.
> Probe the plates, not the end contacts.
> All the stator plates should read at DC ground (through
> the tank coil).  If they do not, a Hi-Z contact point has
> developed between the stator plate stack and the metal
> strip pressed onto the end of the stack as a connnection point.
> Solder one of the pressed connection points with a sturdy iron, being
> careful not to destroy the plastic
> beads that mount the stators.
>
> Hope this helps.
>
> 73 Dave AB5S
>
>