[SignalOne] CX7A

[signalone@mailman.qth.net]

I bought the basket-case CX7A on eBay recently.

This is the one that came "Guarenteed to arrive dead,  if this
radio starts to work within 30 days, return for a full refund."

No powercord, 4CX350F, wiring harness hanging out the back, voltage
regulator connect to aft key jack, loose push buttons.  Did not come
with the Beryllium block or the heatsink.  Did not come with the
power supply for the 4CX350F.  Did not come with the blower or external
ductwork for the 4CS350F.

A fellow (not the seller, someone who wanted to help out) sent me a
powercord. The radio powered up.

Jitter on the 100 Hz digit.  

Dead PTO-B

I opened PTO-B and fixed the tuning slug by glueing it to the carrier.

Audio is strong, dual receive works.

Passband tuning works.

Keyer works but I can't use it.  It doesn't buffer the dits the way my
TTL keyer does.

Only has one CW filter, no AUX crystals.

The QSK works.  I can hear the CW on another receiver but it is very
weak.

I'm hoping that the power transformer is good and that the wiring
harness is intended to deliver higher voltages to the 4CX350F. 

Good S-Meter action, no indication of transmitter output. 

Noise blanker works.

Seems sensitive and stable enough.  About the same as my SB-303. I have
an SB-303 that is stable within a couple hundred Hz over a week and has
dual cascaded 2.1 kHz filters.  

So, here's the problem. I'm thinking about restoring the radio to use
an 8072.  I've read about problems with 8072.  What's the story with
the 8072 and what's the deal with the 4CX350F?  It's mentioned the the
Sullivan manual but no details.

I don't have the CX7A hardware for the 8072 but have an offer of some
GE landmobile RF power modules that include 8072's. 

Mostly I work on Heathkits (simple construction, detailed manual), this
is a challenge.

de ah6gi/4