[TenTec] Low (to no) Power Out Omni D--han'nt given up yet

[Mike Bryce]

Actually, you'll learn more about how things work when they don't work. 

First.  DO NOT DIDDLE the coils on the band pass board. They rarely fail and they are as broad as a barn door. 

The alc is derived by a diode on the swr / filter board. When the PA is over driven the diode produces a voltage that follows the PA output. That voltage is applied to the LLD board   

There it is used to turn on the ALC led and at the same time it reduces the gain of the LLD. The ALC set point is the trimmer on the pcb. 

When the ALC exceeds the set point a Zener diode conducts and then through a pair of transistors lowers the gain of two more transistors. I'd be more specific but I am at work and pulling this out of my head. 

With no ALC voltage from the PA ( no output) the LLD will by default be set for max gain. 

So a open ALC diode won't cause low power as the PA would no longer be under control of the LLD   

In this case, the PA would draw excessive current and pop the breaker in the supply. ( a ten tec ps ) 

Now I may have missed it but did the radio fail during use or did you turn it on and nothing? 

Remember, a screwdriver won't fix a broken radio so leave the adjustments alone for right now. 

And...

Consider yourself lucky. 'Cause if you're pushed into a corner, you still have an out. 

You can still send it back to the factory. 

That in itself is why I have been and will continue to purchase my ham equipment from Ten Tec for I know if I can't fix my TT 315 receiver that's almost 40 years old, they can. 

That speaks volumes. 

Had you been working on a FT-301, Yaesu would had told you "sorry for your bad luck."

Mike wb8vge

Sent from my iPhone

On Feb 16, 2012, at 12:26 PM, scottsheppard at videotron.ca wrote:

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