127
July 2010 50PJ350 Plasma
Soft Touch Key
Soft Touch Key
Pad Resistance
Pad Resistance
and Diode Mode
and Diode Mode
Checks
Checks
P100 (Key 1, Key 2) Resistance Reading with Soft Touch Key pressed.
Menu
Enter
Volume (-)
Volume (+)
KEY
9K Ohms
22K Ohms
0.62K Ohms
3.6K Ohms
Pin 4 measured
from Gnd
3.66K Ohms
9K Ohms
0.61K Ohms
Pin 3 measured
from Gnd
Input
CH (Dn)
CH (Up)
KEY
P100 Voltage Measurements with Soft Touch Key pressed.
P100 Connector “IR/LED Control Board“ to P703 “Main” (No Key Pressed)
KEY 2
KEY 1
Label
3.3V
3.3V
STBY
1.58V
3.29V
4
2.58V
3.29V
3
Diode Mode
Run
Pin
Diode Mode
Readings taken with
all connectors
Disconnected. Black
lead on Gnd. DVM
in Diode Mode.
Menu
Enter
Volume (-)
Volume (+)
KEY
1.667V
2.42V
0.214V
0.89V
Pin 4 measured
from Gnd
0.88V
1.619V
2.1V
Pin 3 measured
from Gnd
Input
CH (Dn)
CH (Up)
KEY
IC100 on the Front IR
Board is generating
these Resistance
changes when a Soft
Touch Key is touched.
This in turn pulls down
the Key 1 and Key 2
lines to be interpreted
by the Microprocessor.