W
Wdyorchid
Guest
Your help sound exciting. I've been searching for a scope the past few weeks.
When I get one I will try it.
Today I'd pulled out the last transistor (Q105) and tested it and it's
fine. I'd used a light bulb connected in series with collector (C) and emitter
(E) ground and inject currant into B with a logic pulser. It works okay. But
reversing (C ) and (E) makes the bulb glow dimly, this is normal I believe.
This transistor I cannot find an exact replacement part.
C113 sounds like an exciting task to replace and find. I will get on it
right away.
Thanks for the great quality help.
-w orchid
When I get one I will try it.
Today I'd pulled out the last transistor (Q105) and tested it and it's
fine. I'd used a light bulb connected in series with collector (C) and emitter
(E) ground and inject currant into B with a logic pulser. It works okay. But
reversing (C ) and (E) makes the bulb glow dimly, this is normal I believe.
This transistor I cannot find an exact replacement part.
C113 sounds like an exciting task to replace and find. I will get on it
right away.
Thanks for the great quality help.
-w orchid
The best ( cheap ) way to check junction transistors for shorts and/or
excessive leakage is to make a curve tracer using an old " lab " scope
, and about a 3-6 volt transformer , email me , and I will try to
hunt-up or simulate details ( scope must have a horizontal-drive input
)
total cost , besides scope , the price of salvage transformer and
switch and resistor ( s ) 3 if you want a good one , but 1 resistor
will do .
tim
wdyorchid@aol.com (Wdyorchid) wrote in message
news:<20030822041804.10910.00000511@mb-m14.aol.com>...
Take a look at this schematic. The green line is faulty line measuring 28V
which should be 1V. Assuming that replacing four transistors in these
general
areas would solve it, but it didn't. What can I be missing?
Details: Q111, Q109, Q129C, and Q129A replace same time. Measurements were
taken and still the same as before. (Thinking Q111, Q109 drives the output
transistors (Q129A, Q129C, replacing them would solve something) All the
transistors were checked with a diode tester but didn't paid attention to
comparing them before installing them. What is the correct way to test them
with a diode checker? (I'd been using a logic pulser before but lost it.)
Receiver is a Dolby pro logic RX-V480.
http://autotails.tripod.com/zoom.htm