"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.