HITACHI P42H401, P42H4011, P50H401, P50H4011, P55H4011 Training Manual
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Version 04 (02/05/2008)
DW-3 NO PICTURE TROUBLESHOOTING Page 1 of 10
DW-3 CHASSIS PLASMA DEFECT TROUBLESHOOTING PROCEDURE.
The Below Information relates to investigations related to a Defective Plasma when there is no Picture at all.
Use this section for P42H401, P42H4011, P50H401, P50H4011, P55H4011 and P55H401 and P42T501,
P50S601, P50V701, P50X901, P50T501, P55H401, P55T501 and P60X901 Plasma Television.
No Picture:
1. The Power Supply may not be producing the correct voltages.
2. The Digital Module (Digi-Main) may not be producing correct
turn on commands (Power 1 and 2).
3. The Logic PWB may not be supplying the correct Vs/Va turn on
commands (Vsago and Vcego).
The Panel can have a defect of two natures.
1. The panel is shorted.
2. The panel is defective, but not presenting a short.
3. Y-SUS and/or X-SUS may be defective (Shorted and or non-
working).
First monitor the front Power LED.
• Does it turn on, then go completely off? (Indicates Shutdown), Power Supply not running.
• Does it turn on and stay Green, but no picture. (No Shutdown),
• Power Supply running basic power supplies, but Vs/Va voltages not being produced.
PRELIMINARY OBSERVATION:
Next open the unit by removing the back cover. Check the following carefully by visual observation.
Power Supply PWB: Look very carefully around all mounting screws for cracks or PWB damage.
(Shutdown usually indicates a Short.)
NOTE: It would be very helpful is you have
one other document to accompany this one.
(On our web site, see these models Things
You Should Know section Power Supply
Issues to download these documents.)
DW-3 Power Supply Explanation.pdf
http://www.hitachiserviceusa.com/service/
Seminars/Plasma-Web/DW3-Web/Fixes/
00-Things-Known.htm
BUFFERS (Drivers) ON SDR Upper and/or Lower PWBs (50”~60”)
Take a moment to carefully observe the Buffer “Snot” Chips
(Left Side black chips mounted on the SDR Upper and Lower PWBs).
Look very closely for burns and/or small holes in these chips.
If any defect is seen, the PWB is defective. Replace this PWB and
the Y-SUS if PWB not upgraded. Replace only SDR if PWB is upgraded
SDR U / L
COF (Chip on Film) from Panel to A-BUS (42”)
Take a moment to carefully observe the COFs Chip on
Film (Mounted on the flexible ribbon cables).
closely for burns and/or small holes in these chips.
Look very
Look very closely for any ribbon cable damage on the
connections to the Panel itself from the
A-BUS PWBs.
If any defect is seen, the Panel is
defective. (Note, some additional disassembly is required
to see these COFs as they are on the underside of the ribbon cable coming from the panel to the A-BUS L, R and
C PWBs.)
HOLES
BUFFER BUFFER
See Web site Things You Should Know
Picture Issues Item 25 to determine if PWB
is upgraded.
TO PANEL
COF COF
TO A-BUS CONNECTOR
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DW-3 NO PICTURE TROUBLESHOOTING Page 2 of 10
PWB QUICK CHECK:
Look for any burns, open fuses, etc... If burns found, then replace the PWB.
If fuses open, first check for low ohms condition before replacing the fuse an attempting to turn on the set.
VOLTAGE CHECKS: (When AC applied, then when the Power Button is pressed)
WHEN AC FIRST APPLIED: When AC is first applied, the power supply should turn on and supply the
following voltages for a little more than 2 minutes.
• Stand-By voltages (SBY 5V), (SYB 3.3V on some models) and all voltages on the CNPPS connec-
tor? (This requires Power 1 and Power 2 commands being high coming from the Digi-Main PWB
CN63). After approx. 2 minutes, (unless Quick Start is on), a relay click is heard and the CNPPS
voltages turn off.
If Quick Start is on, the Power 1 and 2 commands remain high and all above voltages remain on.
WHEN THE POWER BUTTON IS PRESSED: When the power button is pressed, the Logic PWB sends
Vsago and Vcego commands to the power supply via the CN64 connector.
• Note: There are two conditions the set can be in before the power button is pressed.
1. If Quick Start is off, the Power 1 and Power 2 commands are output from the Digi-Main PWB
after a short internal self diagnostics is run.
2. If Quick Start is on, the above does not happen because the Power 1 and 2 commands are
already high as stated in “When AC is First Applied”.
Are you generating the Vs and Va voltages. (This requires the Vcego and Vsago commands being high coming
from the Logic PWB CN68 connector).
42"
Va CN64 pin 1
Vs (85V) CN64 pin 7.
-Vs (-85.5) CN64 pin 9. (New for the DW-3 Chassis)
50"
Va (60V) CN64 pin 1
Vs (80V) CN64 pins 8 or 9 or 10.
Note: There is a great deal of information on our web site about how to Force the Power Supply to produce
all of the above voltages to check the Power Supply PWB and how this Power Supply generates voltages.
(See this models Things You Should Know section Power Supply Issues for information.)
http://www.hitachiserviceusa.com/service/Seminars/Plasma-Web/DW3-Web/Fixes/00-Things-Known.htm
IMPORTANT NOTE: FOR CONDITIONS 2 and 3 BELOW IN THE DW-3 SERIES:
Any Time Vs/Va voltages do not appear and a test is made, each time a new test is to be made,
• Press the Power Button and Turn the Plasma OFF.
• Wait until you hear a "Click".
• Unplug the CN68 connector.
• Re-Plug the CN68 connector. If this is not done, the Turn On command for Vs/Va at Pin 7 and 8 of
the CN68 connector will not happen.
• Additional Note: If the Connector CN-68 is pulled and voltage readings are taken on the CN68
connector at the Power Supply, the STB 3.3V will be present at pin 3. There will be no voltage at
pin 1.
This answer to Are you Generating Vs and Va voltages will be;
1) Yes (Green Power LED will be always on)
2) Brief rise the collapse (Green Power LED will go Green then Go Off or may stay Green)
3) No (Green Power LED will go Green then Go Off or may not go Green at all)
There are three possible answers, see next page for Troubleshooting based on your response:
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DW-3 NO PICTURE TROUBLESHOOTING Page 3 of 10
If the answer is 1) Yes (Green Power LED will be always on)
This indicates your providing Vs and Va voltage to the X-SUS and Y-SUS PWBs. Use an Analog Scope. Look at
the outputs from the X-SUS and X-BUS. Use the Top Pin of the connector going to the Panel, on either side.
See if there is activity.
Top pin to Panel Y-SUS PWB 460V p/p
Top pin to Panel X-BUS PWB 29V p/p
No Activity will usually indicate a defective PWB.
But if no activity is seen, before condemning the PWB,
pull the Ribbon cable from that PWB to the Panel and check again.
If activity returns, this will usually indicate a defective panel.
Remember: You have to pull all Ribbon Connectors before condemning the
PWB.
If the Panel is defective with this process, in most cases evidence can be seen
on the screen.
Example: If the top ribbon cable is pulled, the Top of the screen will be
black, but the bottom will have raster.
If the answer is 2)
(Green Power LED will go Green the Go Off) Brief rise then collapse of the Vs and Va voltages.
This indicates a "Load" on the line.
Pull the CN-64 connector feeding Vs/Va voltages to the X-SUS.
Take an ohmage reading from the Va and Vs lines on each PWB.
This means you have to read the Connector on the Power Supply and the pulled connector going to the X-SUS.
See if there is a low value. Low value indicates a defective PWB.
Normal reading should be infinity. (Using the diode mode on the DV/Voltmeter, there will be a brief charge
time, then infinity.) In other words, it may appear as a low ohm reading, but should rise to infinity or open.
(Also not, if there is a charge on the line, the meter may show a low. You must Pull the CN68 connector and take
a reading again).
The line should now be infinity when reading the Power supply pins for Va and Vs and when reading the
connector going to the X-SUS PWB.)
If a Low is see on the connector, pull the CN32 Connector. (Bottom right hand plug on the Y-SUS PWB).
CN32 feeding Vs/Va voltage to the Y-SUS PWB.
Y-SUS PWB.
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