[GreenKeys] SBT-1 Progress report #2

[telegrapher at att.net]

After getting the primary voltage meter to read correctly i was ready to 
proceed with the power up process.

As i had the power amp also installed and hooked up, the paperwork says 
i could turn on the Transmitter voltage and High voltage switches and 
see the proper lights come on.  NADA.  Now what.  Nothing is simple 
anymore.  Another jug of water please.

Checking the PS-4 schematic i see that the bias voltage runs through the 
control relay to the timer tube. Also the other relay and overload 
circuit breakers have this voltage running through them.  Must be that 
a) either the bias voltage isn't there or b) the timer tube isn't 
working.  Egads.  Pull top cover off of the PS-4 and stare at the timer 
tube.  I should have one of them around here someplace.  Check junkbox. 
  Nothing but 26NXXX type timer tubes.  Go back to staring at schematic. 
  Well if i pull the tube out and apply a ground at pin 5 of said tube 
it should pull in control relay as that's part of the operation.  Apply 
power again.  But instead of pulling the tube i just watched to see if 
the time delay tube actuated.  Shortly i hear a click and other tubes in 
the various regulator circuits light up.  AHA!  That part of the circuit 
is working so there must be bias voltage.  WHy no HV nor transmitter 
power lights?  Back to the paperwork.....

Tracing the bias line i see it goes not only through the control relay 
but through the 3 overload circuit breakers and another relay out to the 
PA through 4 interlock switches, back into the PS-4 and then down into 
the PS-5  HV supply, through a couple more interlocks and then back to 
the transmitter on Switch.  Just what i need.  More water please.

I disconnected the cable from the PS-4 going to the RF amp and placed a 
VOM across pins D and E.  No short.  Open contact in the Amp.  I 
subsequently found that the bottom cover interlock was not functioning. 
  The pin that slides back and forth making or breaking the contact was 
bent.  Straightening it out corrected the interlock problem.  I now had 
continuity through that cable and piece of gear.  I had already checked 
the wiring through the PS-5 HV supply so now should be good to go.

Reconnecting all the cabling, replacing the Amp into the rack (ugh, 
heavy and awkward).  Hook AC back to the unit and turn on AC.  Lots of 
blower noise which is a good sign.  After a few minutes and another jug 
of water cause i'd been doing a lot of sweating over this, and 
determining that things were not smoking anyplace, i turned on the 
transmitter switch and then the HV switch.  VOILA!  There are now red 
and green lights showing voltages are present to the amp and meter 
readings are also there.  150 Ma resting current.

It's gonna work.  Now to get the GPE-1 hooked into the system to see if 
it will generate power, fix the VOX and SBE units and i'll be generating 
RF!

Life is getting better in my advancing years......

Larry
W0OGH