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EN 22
5.
FTP2.4A AA
voltage that is still on the circuit can not disappear through the
speakers).
5.8
Repair Tips
5.8.1
Power Supply Unit (for Fujitsu - FHP - plasma displays)
Below a troubleshoot sequence for the FHP power supply is
given (so this is not valid for the SDI power supply, this is
explained further on).
Stand-by Supply
1. 400V present?
2. +9V_STDBY, +5V_STDBY, and 25V_HOT present?
Preconditioner
1. Relay 1450 and 1440 "on" = switch "on" and supply "on"
(LATCH= "H" and STANDBY= "L").
2. 400V or rectified mains present on item 2616?
3. 40V present on item 2664?
4. 15V present on item 2662?
LLC Supply
1. 25V_HOT (from Stand-by supply) present?
2. 25V_HOT_SW (from Preconditioner) present?
3. 17V on pin 15 of item 7001 present?
4. Vcego= "H" and LATCH= "H"?
5. Vrs present? (Vrs=Vs/67).
6. Remark: Vs_unswitched = 65V when switch 7050 is open.
Va Supply
1. Vs_unswitched present?
2. 30V on item 3133 present?
3. Vsa_control= "L" (Vsago= "H" and Vs_lowlim= "H")
4. Vra present? (Vra=Va/48).
Vcc Supply
1. Vs_switched present?
2. Vccgo= "H"? (Vcego= "H").
Vs (switched)
1. 95V present on cathode of item 6054?
2. POK= "H" and Vsa_control= "L"? (POK= "H" when Vs, Va,
Vcc, 12V, and 8V6 are above their lower limit)
5.8.2
Power Supply Unit (For Samsung - SDI - Plasma Displays)
This PSU is for Service a "black box". When defective (this can
be traced via error-codes in the error buffer, or by strange
phenomena), a new panel must be ordered and after receipt,
the defective panel must be send for repair.
1
Figure 5-9 SDI PSU Alarm board
Service Modes, Error Codes, and Fault Finding
5.8.3
F_15460_079.eps
140405
A simple troubleshoot method for the SDI PSU is given below
(see also the SDI PDP repair manual, mentioned on the front
page).
When the TVis in protection check the LED on the PSU Alarm
board (see [1] in figure "SDI PSU Alarm board"). In normal
working mode, this LED is "on". However, if this LED is blinking,
the PSU is in protection. See table:
Nr. of blinks
Fault Description
1
V
block problem
A
2
12V block
3
D5VL
4
D3V3
5
V
S
6
V
/V
CC
G
7
V
SET
8
V
E
9
Thermal protection
10
PFC_OK
11
OVP
12
Time_Over
13
V
SCAN
3V3 Supply (DC/DC Converter On The SSB)
As mentioned above, the DC/DC converter is switched "off"
when something goes wrong (detection of a missing 3V3
supply at one of the devices supplied by the 3V3). Because of
this, the TV goes to protection (I
is logged.
For further diagnoses, you need to overrule the I
put the TV in Service Default Mode by means of the solder
pads on the SSB (see figure "Service pads").
The DC/DC converter is still not working because it is switched
"off" by the 3V3_FAULT line (schematic B12). Now you have
some possibilities:
1. First, measure the impedance over diode 6U06. In normal
conditions, you should measure approximately 120 ohm (if
possible, verify this with another set). If the impedance is
much too low, do not try to start up the converter as
mentioned below. Remind that if FET 7U03 is short-
circuited, this will also influence your measurement.
2. Desolder coils 5U05 and 5U06, connect an external 3V3
supply at capacitor 2U23 (current limitation to 500 mA) and
a second external 3V3 supply at capacitor 2U31 (current
limitation to 800 mA). The normal working current of the
3V3_SIM line is approximately 400 mA and the normal
working current for the 3V3_DCDCFBX line is
approximately 700 mA. Therefore, if one of the currents
exceeds their nominal value you can determine in which
circuit the overload is situated. If the TV would start up and
you have normal picture, there is probably no overload but
a problem in the detection circuits.
3. If you do not have two external power supplies, you can do
the following: Desolder coils 5U02, 5U03, and 5U04 (you
must desolder all three, otherwise the circuit could be
damaged), connect an external power supply of 3V3 at the
cathode of diode 6U06. Make sure to limit the current of this
external supply to approximately 1200 mA. If the supplied
current exceeds 1100 mA (approximately normal working
current) you can conclude that one of the devices supplied
by 3V3 is short-circuited.
4. Another possibility is to force the converter to start up by
short-circuiting (and keep short-circuited) resistor 3U25
(B12).
Caution: Be aware that this can damage the TV. Even if
you measure approximately 120 ohm over diode 6U06,
there can still be something wrong in the converter itself.
By short-circuiting resistor 3U25, the internal protection of
the converter is disabled.
Remark
Display voltages
Display voltage
Display voltage
Display voltage
Display voltage
Display voltage
Display voltage
Display voltage driving signal
Overvoltage protection OR DC-prot
A control signal to the PSU is missing af-
ter a certain time period
Display voltage
2
C protection). Error code "55"
2
C protection:
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