Troubleshooting The Hammer Driver Transistors - Tally T6090 Maintenace Manual

T6090 Maintenance Manual

Troubleshooting The Hammer Driver Transistors

3–20
The Hammer Driver Transistors are located on the Engine Controller CBA. When you
are having problems like Hammer Coil shorting or Hammers not firing, these compo-
nents should be checked along with the other components involved in the function.
To check the Hammer Driver for the malfunctioning hammer, use an Ohmmeter on its
lowest scale. Test the collector (C) to base (B) by placing the Positive (+) lead on the
collector terminal and the Negative ( – or Common) lead on the base terminal. If the
reading is either a short (0 Ohms) or an open (∞, infinity), the driver is bad and you
should replace the Engine Controller CBA. If this check is OK, then test the base (B) to
emitter (E) by placing the positive (+) lead on the base terminal and the negative (– or
Common) lead on the emitter terminal. If the reading is either a short (0 Ohms) or an
open (∞, infinity), the driver is bad and you should replace the Engine Controller CBA.
Use the following table to locate the correct driver terminals to check for the hammer(s)
you are having trouble with.
The Base of each segment of the driver goes to the LSI Chip, which turns On/Off
each segment. The Collector of each driver segment is connected to the corre-
sponding Hammer Coil.