Star Tech Journal

June 1996
CD
STAR*TECH
... continued from previous page.
170VDC then regulated down to
transistors: those that contain an
120 or 130VDC 'by a large pass
internal damper diode and those
transistor. A couple of brands use
that do not. This is a crucial dif-
different transistors in almost
ference. Whenever you sub a
identical circuits. So it is pretty
H.O.T. you must use the same
likely that the transistors can be
type. Check the symbol on your
interchanged. Verify this by
schematic. The damper diode
checking specs in the transistor
will either be inside the transis-
manual. Monitor color gun
tor or it will be a separate com-
driver transistors are another ex-
ponent. The 2SD870 has the di-
ample of similar parts across sev-
r;::==:=2:::1J£=:c:===::::::::::=::m:::i::m::m=:m::::::::m:::::::::::::aCL, eral brands.
Monitor
Proble111s?
Order This Tech Pub
J\-te>NITORS:
SYMPTOMS/ SOLUTIONS
I
-
Though I stay away
from them as much
as possible because
of the high cost, you
can use the ECG,
NTE, SK replace-
2
ment series or simi-
PIN 1. EMITTEA
1 o o
O J
lar. They usually
2. BASE
3. COLLECTOR
work. I have one
{Pin 3 connected 10 caH)
note of caution.
Please be aware that
when you look up a
part in the ECG
CASE:~
cross
reference
PIN 1. EMITTER
guide,
it
does
not tell
2. BASE
3. COLLECTOR
1
you the specs of
your part, it only
tells you the specs of
the part they would
have you use in its
place. The guide is
PIN 1. EMITTER
2. BASE
good
for something
3. COLLECTOR
4. COLLECTOR
else: identifying the
functions and con-
nections of I Cs. In one handy
ode and a 2SC 1308 does not. The
volume you can find the pinouts
damper diode is doing the same
for many of the I Cs we use.
job as the one across a solenoid
coil.
Rather than pay through the nose
for ECG types, I make my own
Check other similar circuits for
replacements. My semiconduc-
suitable subs. A common moni-
tors are in drawer bins sorted by
tor circuit is the linear power sup-
ply. The main AC line is recti-
fied and filtered to about
... continued on page 16.
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