Gareth Magennis wrote:

"Gareth Magennis" wrote
"EADGBE" wrote

In the interest of clarification, I have added some information to the
schematic of the tape deck headphone amp that I'm having problems
with.

Some circuit paths are now labeled:

http://i240.photobucket.com/albums/f...mplifier-1.jpg

As always, the points at which voltage readings are marked with a star
are NOT producing the voltage indicated. The +7V location is
measuring 131mV instead. The other two points where a star is
indicated are measuring between 20mV and 30mV (fluctuating slightly).

I am starting to think that a circuit OUTSIDE of this circuit might be
at fault, because NOTHING inside of this circuit seems to be
faulty...but the darn thing still WILL NOT work.


Make sure your transistors are oriented the right way round, i.e. B,C & E
really are where you think they are. I remember once being stuck with a
repair where the lead out of a replacement transistor was not the same as
the original. Couldn't work out what the hell was going on for quite a
while, but C and E were reversed. (don't just use a diode check for this)


As an example: BC184

Centre base ('TO-18 style').


and BC184L

Base at one end.


have different pinouts.

Gareth.