[SBE] Gates FM Solidstatesman TE-3 Exciter

[Curt Yengst]

Success!  (So far, anyway....)
 
One of the variable capacitors on the power amplifier stage was out of adjustment.  A little tweaking, and the exciter is doing 10 watts easily.  And it stays on frequency to boot!
 
Now to get some audio into it.
 
 

________________________________

From: sbe-bounces at sbe.org on behalf of Curt Yengst
Sent: Wed 6/10/2009 11:07 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