[SignalOne] WG: Signal/One Service and Repairs

[Graf Ulrich Ulm]

Hi Paul,

just some information I want to let you know...

Helmut Hengstenberg, a friend of mine living in Stuttgart/South =
Germany,
owns two CX11A and two Milspecs 1030. One of the CX11A had a blown PA =
and I
ordered transistors from RF Parts. When installed, these more modern =
series
of transistors exhibited a much greater gain and the PA started to =
oscillate
whenever activated. The easiest way to stop the oscillation was  by
introducing a negative feedback. So I inserted some low inductance =
resistors
with short leads between collector and base of both final transistors =
with a
final value of about 70 Ohms and 2 W. This measure reduced excessive =
gain
and stopped oscillation completely. Gain was readjusted and the radio =
was
working as well as before.

Since this might happen quite often with moderns transitor substitutes, =
it
could be of interest to you as well.

Best 73

Uli, DK4SX

-----Urspr=FCngliche Nachricht-----
Von: PKluwe@aol.com [mailto:PKluwe@aol.com]
Gesendet am: Montag, 7. Januar 2002 23:20
An: Graf Ulrich Ulm
Betreff: AW: Signal/One Service and Repairs


In a message dated 1/7/02 9:29:32 AM, Ulrich.Graf@ulm.siemens.de =
writes:

>very interesting... I always thought the milled and golden colored =
aluminum
>receiver frame was standard with this radio.=20

The first 30 units had different shielding on the receive board, it was =
thin

metal pieces soldered together.  These receivers were awful, and most =
were=20
replaced.  Units 30 to 40 had shielding similar to the milled aluminum =
and=20
were thicker aluminum bard screwed together.  After unit 40, the =
shielding=20
was on piece aluminum anodized dark gold.

>It seems to me, that the development engineer had some problems with =
the
>synthesizer locking at first. Therefor the A24 module was added later =
to
>define lock status. The A24 module in my radio was handmade (different
>circuitry as in the handbook) in a pcb material case. Also the cables =
to
>this module were added later. Do you remember such a module/radio?=20

This describes the first 30 units pretty well.  Most were ultimately=20
updated/replaced by the factory, some at *very* high cost to the =
owners.

>I could actually not find out wether my radio has a 150W or 200 W =
final
>amp.It has the vacuum relay. But heat sink seems to be much too small =
to
>dissipate full power, even only in SSB. Most of the S/Os I got for =
repair
>had a blown final amp and 24 V regulator.=20

The "high power" units are identical to the low power units except they =
have

a vacuum antenna relay and the blower kit installed behind the rear=20
heatsinks.  There were also some timing problems in the QSK circuit =
that=20
would harm the relay (and other things) with the power greater than =
about
135=20
watts.  This was the same with the CX11A transceiver.  Putting in all =
of the

modifications and having the blower kit is *still* not enough to run =
200=20
watts output for a high duty cycle.

>As far as I know, this radio was possibly bought from a German =
distributor
>named "Disselhorst Elektronik". Ever heard about over there?

I am not familiar with them.  I don't think many of the 1030's were =
sold.

73,
-Paul   W8ZO