Samsung PN19MT-MO-IO, PN19MT9U Troubleshooting
PN19MT/MO/IO
x178/19P2
5-1
5 Troubleshooting
5-1 Parts Level Troubleshooting
Notes: Check the following circuits.
• No raster appears: Power circuit, Horizontal output circuit.
• High voltage develops but no raster appears: Video output circuits.
• High voltage does not develop: Horizontal output circuits.
5-1-1 No Power Supply
Check and replace D606, IC620,
D647, and D640.
Check and replace FG601, D601,
D701, Q701, IC601, and ZD601.
Done.
Yes
No
Repeating start?
Check and replace
D620, IC601 and IC701.
Yes
No
IC601 Pin 1 waveform is right?
Check and replace ZD705, ZD706, D702,
and also check the secondary diodes.
Yes
No
IC701 Pin 8 Voltage is right?
Replace Main board.
Yes
No
Operate normally?
Yes
Verify voltages.
WAVEFORMS
1
1
100 V (IC601, #1)
CH1 P-P = 100 V CH1 RMS = 350.2 V
5 Troubleshooting
5-2 PN19MT/MO/IO
x178/19P2
5-1-2 DPMS Failure
Make No H/V Sync. (power off mode)
Check signal source
H/V Sync. video level.
LED blinks?
Check IC201 Pin 39.
Yes
No
Q620 Base drive voltage?
Check IC201 Pin 10.
Check and Replace Q403.
Yes
No
Is there 12 volt?
Check IC201 Pin 9.
Check IC651.
Done
Yes
No
5 Troubleshooting
PN19MT/MO/IO
x178/19P2
5-3
5-1-3 H_Deflection Failure
IC250 Pin 26 waveform is right?
Check IC250.
Yes
No
Q401 Gate Drain waveform
is right?
Check IC250 Pin 26.
Check Q401, R404 and 25V line.
Check Q250, Q251.
Yes
No
Check some parts around
IC261 and Q262.
WAVEFORMS
6
3
210 V (Q454, Drain)
CH1 P-P = 210V CH1 RMS = 302V
4
66.4V (Q401, Drain)
CH1 P-P = 66.4V CH1 RMS = 25.84V
5
1.24kV (Q402, Collector)
CH1 P-P = 1.24kV CH1 RMS = 302V
Q454 Drain waveform is right?
Yes
No
Check R467, Q454, D456,
and +210V line.
Check ZD450 and IC402 Pin 6
3
4
2
Yes
Q402 Collector waveform
is right?
5
Check and replace D403 and Q402.
Check DY connector connection.
No
2
13.0 V (Q401, Gate)
CH1 P-P = 13.0V CH1 RMS = 7.91V
6
11.0V (IC250, #26)
CH1 RMS = 11.0V
5 Troubleshooting
5-4 PN19MT/MO/IO
x178/19P2
5-1-5 H_Lin. Failure
IC201 Pin 21 voltage varies with
different H_Lin. DAC values?
IC403 Pin 7, 8 voltage varies with
different H_Lin. DAC values?
Check+12V line.
Check some parts around IC403.
Check L403.
Yes
Yes
No
Replace IC201.
No
5-1-6 Invariable H_Size
IC201 Pin 20 voltage varies with
different B_Out DAC values?
IC402 Pin6 Voltage Varies with
different H_Lin. DAC Values?
Check and replace IC402.
Yes
No
Check and replace IC201.
No
7-1-4 S Correction Failure
S1~S3 signals are right at each
frequency block?
Check S1 ~ S3 signal.
Check and replace C411~C418,
Q408~Q411, Q403~Q407.
Yes
Check and replace IC201.
No
7
WAVEFORMS
7
13.6 V (IC402, #6)
CH1 P-P = 13.6V CH1 RMS = 9.02V
5 Troubleshooting
PN19MT/MO/IO
x178/19P2
5-5
5-1-8 Side Pin or Trap Failure
IC250 Pin 24 output exists?
Check and replace IC250.
5-1-9 Para. or Pin Balance Failure
IC250 Pin 24 output varies with
different DAC values?
Yes
Replace IC250.
No
WAVEFORMS
9
9
IC250, #24
CH1 P-P = 1.00V CH1 RMS = 3.008 V
5-1-7 Abnormal H_Size
T402 Pin 8 waveform is right?
Check and replace T402.
Check IC402 Pin 6
and IC201 Pin 20 and 22.
Yes
No
WAVEFORMS
8
8
28.0V (T402, #8)
CH1 P-P = 28.0V CH1 RMS = 5.92V
9
5 Troubleshooting
5-6 PN19MT/MO/IO
x178/19P2
5-1-11 V Deflection Failure
14V line is on?
IC250 Pin 23 output exists?
Check and replace IC250.
Yes
Yes
No
Refer to 5-1-1 No Power Supply
No
IC301 Pin 6 output exists?
Check and replace some parts
around R312, R316 and IC301.
Yes
No
Check V_DY connector connection.
WAVEFORMS
10
11
10
1.32 V (IC250, #23)
CH1 P-P = 1.32V CH1 RMS = 1.507 V
11
55.2 V (IC301, #6)
CH1 P-P = 55.2 V CH1 RMS = 8.04 V
5-1-10 Tilt Failure
IC201 Pin 23 output duty varies
with different DAC values?
IC403 Pin 10, 11 output varies with
different DAC values?
Check and replace IC403.
Check and replace CRT.
Yes
Yes
No
Check and replace IC201.
No
Check tilt connector connection
IC301 Pin 1 output exists?
Check and replace R301.
Yes
No
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