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
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.
Consider yourself lucky. 'Cause if you're pushed into a corner, you still have
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
Sent from my iPhone
On Feb 16, 2012, at 12:26 PM, email@example.com wrote:
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