LG 50PK950 Training Manual page 158

Soft Touch Key
Soft Touch Key
Pad Resistance
Pad Resistance
and Diode Mode
and Diode Mode
Checks
Checks
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.
P100 Connector "IR/LED Control Board" to P703 "Main" (No Key Pressed)
Diode Mode
Readings taken with
all connectors
Disconnected. Black
lead on Gnd. DVM
in Diode Mode.
P100 (Key 1, Key 2) Resistance Reading with Soft Touch Key pressed.
Pin 3 measured
KEY
from Gnd
CH (Up) 2.08M Ohms
CH (Dn) 16.85M Ohms
Input 8.81M Ohms
Power 23.24M Ohms
P100 Voltage Measurements with Soft Touch Key pressed.
Pin 3 measured
KEY
from Gnd
CH (Up) 0.21V
CH (Dn) 1.59V
Input 0.86V
Power 2.3V
Pin Label
3 KEY 1
4 KEY 2
KEY
Volume (+)
Volume (-)
Enter
Menu
KEY
Volume (+)
Volume (-)
Enter
Menu
STBY Run
3.14V 3.14V
3.28V 3.28V
158 October 2010
Pin 4 measured
from Gnd
8.81M Ohms
2.08M Ohms
37.3M Ohms
16.85M Ohms
Pin 4 measured
from Gnd
0.88V
0.21V
2.4V
1.65V
Diode Mode
1.83V
1.83V
50PK950 Plasma