Vfo, Vscn-F, & 5V_F Resistance Measurements (Su-Sd Boards) - Panasonic G20 Series Troubleshooting Handbook

Vfo, VSCN-F, & 5V_F
Preparation:
Disconnect AC Power prior to making any disconnection or connection.
Wait at least 2 minutes before the removal of any connector.
Note: If the power LED continues to blink even after the TV is unplugged, press and hold the power switch on the TV
for a few seconds until the LED turns off.
Procedure:
1. Remove the 4 VFG screws from the SU and SD boards. (See picture to the next page (page 44).)
2. Disconnect SC41, SC42, and SC46 from the SC board. Also remove the ribbon cable between the SU and SD
boards (SU11/SD11). (See picture on the next page (Page 44).)
3. Using the VF-Ground (VF_GND) as reference, measure the Vfo, VSCN-F, and 5V-F resistance's on the SU and
SD boards individually. (Use the test points around SU41 and SD42 shown on the pictures on the next page
(page44). The board is considered to be bad is a short circuit or a very low resistance reading is found on any of
these lines.
SC41/SU41
Pin
Number
2
4
8
9
This test is done to determine if the SU, or SD are bad.
While a short circuit found on any of these boards confirms a defective board, a normal resistance reading does not
necessarily indicates that the boards are 100% functional.
If no short circuit is found on any of these boards, perform the SU and SD isolation procedures shown on page 38.
Resistance Measurements (SU-SD boards)
Test Point SC42/SD42
Pin
Around
Number
SU41
TPSU15 1
TPSU16 2
TPSU17 6
TPSU18
Test Point Line
Around
SD42
TPSD29 VFO
TPSD28 VSCN-F (TPSC1)
TPSD26 5V_F
VF_GND
Resistance
Reading with
SC41 Removed
2.2M
221K
5.7M
Reference Ground
Slide 43