[SBE] Gates FM Solidstatesman TE-3 Exciter

[jer hill]

Speaking from no experience with this exciter, why don't you try an O-scope
and check for voltage. You already know the impedance and you should be able
to derive current and power in a relative manner to indicate operation or no
operation. 20 mW should be small enough for a scope to handle.

Jer Hill

-----Original Message-----
From: sbe-bounces at sbe.org [mailto:sbe-bounces at sbe.org] On Behalf Of Curt
Yengst
Sent: Wednesday, June 10, 2009 8:08 AM
To: sbe member discussion mail list
Subject: Re: [SBE] Gates FM Solidstatesman TE-3 Exciter

Section 4.5 of the manual states the following:
 
"Three outputs from the modulated oscillator are as follows:  An RF output
of approximately 500 millivolts into a fifty ohm load for automatic
frequency control (J-2).  An RF output of 20 milliwatts to drive a power
amplifier (J-3) and a DC output proportional to the RF output level that
provides a convenient means of monitoring the RF output of the modulator
(J1-9)."
 
If the RF output of the Modulated Oscillator is supposed to be 20 mW (I'm
thinking it's not...), what would be the correct DC voltage on J1-9?  I
couldn't find anything in the manual or schematics to tell me what it should
be.
 
I'm trying to determine if the the MO is putting out the correct RF power.
My wattmeter doesn't go down to 20 milliwatts.
 
 

________________________________

From: sbe-bounces at sbe.org on behalf of Dan Mammone
Sent: Tue 6/9/2009 11:51 AM
To: 'sbe member discussion mail list'
Subject: Re: [SBE] Gates FM Solidstatesman TE-3 Exciter



Curt,

 

Take a look at section 5.3 in the manual regarding the carrier frequency
issue.

 

[http://sujan.hallikainen.org/BroadcastHistory/uploads/GatesTE3.pdf]

 

Dan 

 

From: sbe-bounces at sbe.org [mailto:sbe-bounces at sbe.org] On Behalf Of Curt
Yengst
Sent: Tuesday, June 09, 2009 11:05 AM
To: sbe at sbe.org
Subject: [SBE] Gates FM Solidstatesman TE-3 Exciter

 

Fellow gearheads:

 

As a rainy day project, I'm in the process of trying to fix a Gates FM
Solidstatesman TE-3 exciter.  A while back, it was putting out enough power
to keep the transmitter happy, but it wouldn't stay on frequency.  After
reseating the socketed transistors on the Modulated Oscillator's PCB, it
stayed put for a while, but began to drift again.  I eliminated the sockets
and soldered the transistors directly to the board.  Now it stays on
frequency.

 

The problem now is that it only puts out about 3.5 Watts instead of 10
Watts.  The only user adjustment on the Power Amplifier is the input drive
control, which is pretty much maxxed out.  If I remember correctly, it was
only putting out 3.5 Watts even before I did the transistor fix, so I'm not
entirely convinced that was the cause of this new problem.

 

If anyone here has experience with this thing, any advice would be greatly
appreciated.

 

Curt