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EN 20
5.
FTP2.4E AA
5.7.3
OTC Related Protections
If a protection is detected at an OTC input, the OTC will start to
scan all protection inputs every 200 ms for 5 times. If the
protection on one of the inputs is still active after 1 s, the
microprocessor will put the TV in the protection mode. Before
the scanning is started, a so-called "ESD refresh" is carried out.
This is done, because the interrupt on one of the inputs is
possibly caused either by a flash or by ESD. As a flash or ESD
can influence IC settings, the HIP, MSP, 3D Comb and wireless
module (not used in this set) are initialised again, to ensure the
normal picture and sound conditions of the TV.
8 V and 5 V protections: The microprocessor senses the
presence of the 8 V and 5 V (via the "+5V_CON" and
"+8V_CON" lines). If one (or both) of these voltages is (are) not
present, an error code is stored in the error buffer of the NVM,
and the TV is put in the protection mode.
Audio Supply protection: The OTC senses if the audio
module is in protection via IRQ-DIGITAL (pin 98 of OTC). If this
is the case, the OTC puts the TV in protection.
5.7.4
Hardware Protection
Short-circuiting the 3V3 supply from the DC/DC converter will
shut down the DC/DC converter. The absence of the 3V3
supply line is also sensed via I
protection above), this is useful if there is something wrong in
the detection circuit of the DC/DC converter.
Audio DC Protection: This protection occurs when there is a
DC voltage on the speakers. In that case, the Main Supply is
switched "off". The Stand-by Supply is still working. For the
Samsung SDI V4 displays, all internal supplies (except the
5V2), are switched "off" and the LED on the Samsung SDI V4
display (on PSU Alarm board) blinks 11 times., which means
there is an overvoltage protection.
Repair tip: If there is an audio DC protection (DC voltage on
your speakers), you will probably see error 18 blink. To be sure
this is an audio DC protection, disconnect the cable between
the SSB and the audio PWB and also the cable between the
Main Supply and the Audio PWB. If the TV starts up, it is very
likely that there is DC on the speakers. Check, and replace if
necessary, the audio amplifiers.
Note: It is also possible that you have an Audio DC Protection
because of an interruption in one or both speakers (the DC
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?
Service Modes, Error Codes, and Fault Finding
2
C (see description Audio Supply
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 5-8 SDI PSU Alarm board
A simple troubleshoot method for the SDI PSU is given below.
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
5.8.3
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
F_15460_079.eps
140405
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
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