Control Board; Y-Sus Board; Y-Sus Board Output Diode Check; Control B/D Trouble Shooting - Philips PDP42V7 series Service Manual

Service Modes, Error Codes, and Fault Finding
Control Board (see figure "Control b/d trouble shooting")
1. Check LED status (normal status lightening or not)
2. If not, check OSC X1 output.
3. Check CTRL input voltage (connector P10).
4. Check each FET (3.3V, 5V, and 1.8V).
Input voltage
Probe
touching
OSC(X1) point
Check oscillating state.
Be careful with physical shock.
Figure 5-9 Control b/d trouble shooting
Vsc check point
(measure over R53)
Vset_dn
adjust
Vset_up
adjust
LED
5 V
3.3 V
1..8 V
DMM – (GND)
Check FET
F_15590_072.eps
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Figure 5-11 Y-SUS b/d trouble shooting
Y-SUS Board (see figure "Y-SUS b/d trouble shooting")
1. Check fuse: FS1 (5V), FS2 (Vs).
2. Check voltages (Vsetup, -Vy, and Vsc).
3. Check diode between GND and Y-SUS output.
4. Check whether output voltages agree with voltages on the
label.
Normal diode value= 0.6 (forward)
Figure 5-10 Y-SUS board output diode check
Vy adjust
(measure over R78)
LGE PDP 5.
Normal diode value = OL (reverse)
Vy check point
Vs fuse
5V fuse
F_15590_073.eps
060705
EN 11
F_15590_074.eps
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