Generac Power Systems TXP - Manual (Page 50)

PRINTED CfRCUIT BOARD
The Printed Circuit Board provides the. necessary components for;
1. Control of those functions■ required.for. engine starting, runn­
ing, and stopping. These functions include:
a. Energizing the Fuel Shutoff Solenoid open and closed, as needed
b. Turning the electric fuel pump ON and OFF
c. Energizing the Choke Heater
d. Controlling Choke Solenoid action
2, Controlling current flow to the .Field .Boost circuit during a start.
This current is delivered..across the brushes and slip rings, to en­
sure the presence of a magnetic field, around ..the Rotor during a start.
Thus, it is never necessary to energize the field,, since it is energ­
ized during every start.
The illustration at right shows
the Printed Circuit Board comp­
onents that can be tested, adj­
usted, or replaced. Maintenance
is limited to (a) replacement of
the 4 Amp Fuse, (b) adjustment
of the Choke Adjustment potenti­
ometer, or (c) replacement of
the entire Printed Circuit Board.
The Printed Circuit Board recept­
acle and its mating connector are
shown at right. Notice the funct­
ions of each pin in the connector
and receptacle.
Pin Wire Nominal
Function
No. No. Value
1 15 12 VOC Battery Voltage to PCB
2 4 6-12 VDC Field Boost current to Rotor
3 90
0 OR 12 VDC
/P i 11 Qinn)
Choke Solenoid
4 20
\ r u 1 o H 1 u 1
0 • 3 VAC Ignition Stator output (Turns PCB
on during start)
5 .— — Not Used
6 14 12 VDC To Fuel Pump, Fuel Shutoff
Solenoid, and Choke Heater
7 10 •0- PCB Ground
8 91
0 OR 12 VDC
(Pulsing)
Choke Solenoid
a 0
^£0
Or
0) 3
•pi:
UU
n__n—TL-n__ n
I
.(i) (D © fp|
© <5) (fii ©
CE
□ □ □ [Il
□ □ □ □
Receptacle
(viewed From Pin End)
Connector Plug
(Viewed From Wire End)
The Choke Adjustment Potentiometer
can be used to increase.. o.r decrease
choke time. To INCREASE, choke time,
turn the adjustment screw clockwise.
To decrease choke time (or increase
"no-choke" time"), turn the slotted
adjustment counterclockwise.
Choke Time
Potentiometer
CAUTION
Be careful not to force the slotted
adjustment past its stops._______________________
Issued 3-78 5.3