"Frank346" wrote in message
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"Radiosrfun" wrote in message
...
Hi,

I have "I believe" - all of his info downloaded and have reviewed it. I'm
going to check your links to be sure I have all. I "usually" do start
with the power supply in any case - unless symptoms guide me elsewhere.
In this case in particular - being "almost" dead - that was the "first"
place I headed. Situation is - I am at a component which is producing
less than it should - and I look to changing it, but in the manual -
there is a transistor shown in the same circuit along with a zener. The
zener is there - the other transistor Q206 "appears" to not have been
placed there. Was just trying to find out what is with that. I'll look
again - but it didn't appear to be on the bottom of the board - and "all"
(as I can see them) traces of the parts shown interconnect on top minus
Q206.
So - was wondering of any changes, etc. And then too - the resistor which
was burned in the center is showing with the first band (not discolored)
to not be as listed in the book. Well anyway, I'll replace the transistor
which isn't pumping out enough and see what it does for me. I can't make
out the resistor other than the first band, so I'll stick one in which
the book called for - and see what goes on. I'll study the thing to see
what was in their mind - then I'll go from there. I've wasted better time
on my own so - trying to help a friend - won't bother me. If I"m not
doing this, I'll be playing taxi driver for family. Would rather play at
the bench!

Lou

Seems like you might have a very early production radio that just doesn't
have Q206. The date code on the back of the radio might confirm this.

The circuit is just an amplified Zener regulator and it isn't extremely
critical if the amplifier is one transistor or two. The service manual
shows a 8.2V Zener and you mentioned having a 9.1V Zener in the radio so
they evidently didn't intend to put Q206 in the circuit. Replace Q204 and
add a small heatsink to keep it from burning out again. The resistor may
look like band one is brown, but heat can change an orange band to brown
over time. Try a 470 Ohm resistor initially. If the output voltage is too
far below 8.4V, the Zener is being starved and the resistor will have to
be reduced. In that case try 330 Ohms and measure the output again.


THANK YOU - very much................. I'll look at the band again, you may
be right - it "was" late! Yeah, I've seen this before - quite a bit in other
radios. But the rest was as stated. As to the Zener - I may be in error -
the book "shows" an 8.2 vdc. I seen the schematic was calling for 9.1 vdc
off one leg of one of the transistors and that stuck in my head. I'll have
to remeasure that too as it seems to me I may just have gotten 9.1 +/- vdc.
I didn't make notes as I usually do.

I'll give this a whirl since I know definately the voltage is "way" off on
the transistor. But as I said - I simply stopped there to try to find out
what the heck was going on with the missing transistor.

I definately have to make notes on this one - regardless if it is fixed or
not - JUST in case!

Thanks again..........

Lou