Star Tech Journal

January 1996
CD
our hand, or tap the PC board with an insulated
object (a stick). Does this affect your symptom? If
so, you have a bad connection somewhere.
Resoldering will likely fix it, I have found several
intermittent connections over the years by turn-
ing off the lights in the shop, tapping on the board
and watching for little sparks at the bad spot. Look
on both sides of the board. This won't work often,
but it is really impressive when it does.
STAR*TEcH
Journal
4 Design Improvements to
the Industry Standard
0
The "Quick Release"
Ticket Dispenser
Improves serviceability
& reduces
maintenance
THE BIG THREE
At this point our approach depends upon the symp-
tom. I sort problems in to three broad categories.
The unit blows fuses, the unit doesn't seem to func-
tion, or the unit functions however poorly with a
problem in some specific area.
MONITOR BLOWS FUSES
Monitors that blow fuses can often be fairly sim-
ply repaired. Most problems that cause fuses to
low can be found in two areas of the monitor:
The power supply and the horizontal output tran-
sistor and transformer circuit. If your monitor has
a secondary fuse in the DC supply line, it will tell
you where the problem is. If the secondary fuse is
blown, then the problem must be farther along in
the system, i.e. in the horizontal section. If the hori-
zontal section is bad, check the horizontal output
transistor (or HOT) for collector to emitter short
or low resistance. The HOT will be a large power
transistor very near to the flyback. Flyback trans-
former and horizontal output transformer are the
same thing. Since the emitter almost always is tied
to ground, we can usually make this measurement
from the transistor case (collector) to the chassis
ground. The base drive to the HOT is almost al-
ways provided by a transformer with one side to
ground. For this reason, we cannot check for base
to emitter shorts in-circuit. Also check resistance
to ground at the HOT collector lead with the tran-
sistor removed. If still shorted to ground, check
r a bad damper diode or a bad cap, especially
Lhe four lead "safety" cap some models use. Fol-
low the printed circuit traces from the HOT col-
-
... continued on page 12
"Quick Release" face plate
Dynamic, new design allows the
ticket dispenser to "quickly release"
from it's face plate on your cabinet
or ticket door, no tools needed.
Easily replace one dispenser with
another in just seconds. No tools
necessary! The new face plate
retrofits any existing Deltronic
Labs machine.
Bottom MET AL ticket guide
The extended, durable ticket guide
prevents curled tickets from catching.
Foolproof braking system
Our impressive new braking system
eliminates brake slippage, allowing
foolproof, accurate dispensing.
Optical sensor dust cover
n a
Eliminates dust accumulation and
increases accuracy of the ticket count.
Another quality product from Deltronic Labs ...
/he mdu"'r leadedn Hckel d ... n,ea
Delfronic Labs, inc.
120 Liberty Lane, Chalfont, PA 18914 • 215-997-7753
FAX# 215-997-9506