Checking For Component Damage; Y Ipm(Ic15) Or Z Ipm(Ic2) Damage; Pass Top Fet(Y B/D: Hs2) Damage; Fet Ass'y(Y B/D: Hs1) Damage - Daewoo DPP-42A1LASB Service Manual

3. Checking for Component Damage

3-1. Y IPM(IC 15) or Z IPM(IC 2) Damage
(1) When the internal Sustain_IGBT or ER_FET of Y IPM(IC
15) or Z IPM(IC 2) is damaged, VS FUSE is open and
screen doesn't be shown.
Test Point: B32~GND(Y B/D), B28~GND(Z B/D)
O
Wave format: B32(Y B/D) or B28(Z B/D) has no output
O
wave.
<IPM Normal Output Wave>
Measurance position: Sustain section enlarge the after
O
measuring B32 wave of Y B/D and B28 wave of Z B/D.
(Full White Pattern)

3-2. Pass Top FET(Y B/D: HS2) Damage

(1) When Pass Top FET is damaged, electric discharge of
entire screen is generated.
Test Point: Enlarge the after measuring GND~B32(Y B/D)
O
Wave format: When the Set_dn does not descend until
O
-Vy.
It does not descend until -Vy
<When the Pass Top FET is damaged>

3-3. FET Ass'y(Y B/D: HS1) Damage

(1) When Set_Up FET is damaged, screen doesn't be shown
Test Point: Enlarge the after measuring GND~B32(Y B/D)
O
Wave format: Set_up waveform does not come out.
O
<When the Set_Up FET is damaged>
(2) When Set_Down FET is damaged, electric discharge of
entire screen is generated.
Test Point: Enlarge the after measuring GND~B32(Y B/D)
O
Wave format: Set_down waveform does not come out.
O
<When the Set_Down FET is damaged>
<Reset section normal output wave>
Measurance position: Reset section enlargement wave of
O
B32(Y B/D) (Full White Pattern)
- 15 -
Set_up waveform
does not come out
Set_down waveform
does not come out