Sony BKM-V12, Service Manual

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2-12
PFM-42X1/42X1N
2-4-3. Checking for Component Damage
1. Y IPM (IC100, 101) or Z IPM (IC4, 5) damage
1) When the internal Sustain_FET of Y IPM or ZIPM is
damaged, the screen is not displayed or electric
discharge occurs.
. Test point : GND to B50 (Y B/D), GND to B35 (Z B/D).
. Waveform : B50 (Y B/D) or B35 (Z B/D) has no
wave output.
2) When the internal ER_FET of Y IPM or Z IPM is
damaged, Y IPM or Z IPM emission increases.
. Test point : GND to B50 (Y B/D), GND to B35 (Z B/D).
.
Waveform : As shown in Fig. 2.
Crushed pulse ocurrance
Fig. 2 When the ER_FET is damaged
<IPM normal output wave>
.
Measuring position : Sustain the enlarged picture after
measuring the B50 waveform of
the Y B/D and the B35 waveform
of the Z B/D (Full White pattern).
2. FET ass’y (Y B/D : HS1) damage
1) When Set_Up FET is damaged, screen is not dis-
played.
. Test point : Enlarged after measuring GND through
B50 (YB/D).
.
Waveform : As shown in Fig. 3.
Fig. 3 When the Set_Up FET is damaged
2) When Set_Down FET is damaged, electric discharge
occurs over the entire screen.
.
Test point : Enlarged after measuring GND through
B50 (YB/D).
. Waveform : As shown in Fig. 4.
Fig. 4 When the Set_Down FET is damaged
<FET Ass’y normal output wave>
.
Measuring position : Enlarged wave of the reset section
of TP B50 (Y B/D) (Full White
pattern).
Set-up wave does not occur.
Set-down wave does
not occur.
Set-down
Set-up