"GAGI-9A6AAG" wrote in message
...

"EADGBE" wrote in message

This headphone amplifier has been REPAIRED and is now working
perfectly.


good4u )

i was folow developing of case you got....i am hobbist to and from my
experience i can tell that malfunctions caused by "cold solder" are most
dificult problems to solve...especiali when there is some random states of
working and it doesnt working...and again...and again...but you cant see
it where does it happening...

even tracking signals is sometimes waste of time...even method of
searching cold solder in dark room (so you can see the sparking
place)...seems sometimes is pure luck that matters! )

Greethings from Croatia...
Gagi



Interestingly, for the most part, I used to find the locating of bad joints,
one of the *easiest* things to do in fault-finding. As well as having sharp
eyes to spot obvious ones, use of the right techniques i.e. prodding,
flexing, heat, cold, and above all, having a good idea exactly *where* to
look, and at what *type* of component, would quickly reveal the source of
the problem.

Sadly, that has now gone 'out of the window' with modern soldering
materials. I have found many bad joints made in lead-free, that have shown
no external physical signs of being bad, such as cracked around, and have
gone good and bad completely at random, failing to respond to any of the
'normal' techniques for finding them. Add to this that my eyes are not as
good as they were 20 years ago (even 5 years ago...) and that *all*
lead-free joints *look* bad with their dull crystalline surface, and I would
have to agree that now, bad joints are likely to turn a job from a
one-coffee money spinner, to a pot-of-coffee frustrating money loser ...
:-(

Arfa