Service Modes, Error Codes, and Fault FindingEM5.1E5.EN 29
of the inputs of the HOP, the relevant error bit in the HOP
register is set to "high". If this error bit is still "high" after 1 s, the Take care not to touch the "hot" heatsink while disconnecting
OTC will store the error code in the error buffer of the NVM and, the SSB, despite the fact that the mains cord is out of the mains
depending on the relevancy of the error bit, the set will either socket. There can still be an annoying rest-voltage on the
go into the protection mode or not.heatsink for a short while. This, because the discharge
resistors 3502 and 3503 (on the LSP between hot and cold
The following protections are implemented: part) are not stuffed for Europe. Instead, discharge resistors
?HFB (Horizontal Flyback): If the horizontal flyback is not 3066 and 3057 on the Mains Switch panel are used, but
present, this is detected via the HOP (HFB_X-because they are located before the Mains switch, they only
RAY_PROT). One status bit is set to "high". The error code discharge when this switch is "on".
is stored in the error buffer and the set will go into the Advice: when you remove the SSB, disconnect the Mains
protection mode.cord, but keep the Mains Switch "on".
?XPR (X-ray protection): If the HFB pulses are too low
(level detection), the HOP will detect this via the XPR-bit. Do not try to measure on the SSB side, which is facing the 'hot'
The error will be logged in the error buffer and the set will heatsink. This is dangerous. Most service test points are
go into protection mode.guided to the 'tuner' side and are indicated by the 'service'
printing.
Note: Both errors will be logged as HFB-failure.Where the circuitry was too "crowded" for service printing, you
can find the correct location on the "test point overviews" in this
5.7.5 Hardware Related Protectionsmanual.
A very large part of the LSP is "hot", such as:
?The primary part of the Standby Supply.
Due to the architecture ("hot" deflection), some protections
?The whole Main supply (except for the secondary Audio
cannot be sensed by the microprocessor. Three of these
supply).
protections will lead to a protection on set level (Standby mode
?And the complete deflection circuitry (so notice that the
and blinking LED), while another will only lead to a circuit
deflection coil is hot!).
protection.
5.8.2 Start-up Sequence
TV-set Protection
The following fault conditions will lead to a "complete" set
protection:COLDHOT
?BRIDGECOIL protection: This is sensed via the "EW"
EHT-INFO
signal going to the base of TS7652 (via R3495 and D6499).
In a normal situation, the voltage on C2498 (diagram A4) is
5START/STOP
high and TS7652 is conducting. When bridge coil 5422 8V17/39OUT
(diagram A3) is short circuited, the voltage on C2498 I2C BUSHOP
1
changes to low, which will block TS7652. In this case, also 29START/STOP
5VCUTOFF
TS7641 will block and the voltage on 2642 will rise until CON(from
CRT panel)
TS7443 is forced in conduction. The "SUP-ENABLE" RESET8VCON2
signal (in normal operating condition -20 V) is shorted now 106105
to ground level, which will force the Main Power Supply to OTC7141
5V220 VAC
99104
Standby mode.POR8VSTBY
?ARC protection: If there are "open" connections (e.g. bad STANDBY7131SUPPLY
low 7131/41 closed
high 7131/41 open
solder joints) in the high-energy deflection circuitry, this can
3
lead to damaging effects (read: fire). For that reason, the E/MAIN
SUPPLY
W current is sensed (via 3479//3480). If this current SUP-ENABLE
Vbat
becomes too high, the "thyristor" circuit (TS7653 and
TS7654) is triggered. TS7442 is switched "on" and TS7443 +11DLINE DEFL.(BRIDGECOIL
-PROT)
is forced into conduction. . The "SUP-ENABLE" signal is POR(ARC-PROT)
7445PROT-
shorted now to ground level, which will force the Main SENSING
Power Supply to Standby mode.FRAME
DEFL
?NON_VFB (No vertical Flyback) protection: If the frame (NON-VFB)
CL16532044_023.eps
stage generates no pulses, TS7641 will block. TS7443 is 140501
now switched "on", which will lead to Standby mode.
Therefore, in normal operation condition, TS7641 and Figure 5-4 Start-up circuitry
TS7652 are conducting, while TS7443 is blocked.
The start up sequence differs from other sets (e.g. MG-sets or
Circuit ProtectionEM2E-sets, but is same as in EM3E-set):
The following fault condition will lead to a "partly" set protection:1. When the set is switched "on", the 5 and 8 V lines
?PROT1 (DC) protection: When a DC-voltage (positive or ("+5V_CON" and "+8V_CON") of the standby power
negative) is sensed on one of the loudspeaker outputs, the supply are activated.
protection circuit (TS7704, 7705, 7706 and 7707 in 2. After the OTC senses them, the P will address the HOP via
diagram A6) will put the IC7700 in Standby mode (via tri-the I2C-bus, to start the drive [1].
state input pin 6). For more details, see chapter "Circuit 3. Via the "SUP-ENABLE" signal, the Main Supply is switched
Descriptions"."on" and will deliver the V_BAT to the Line deflection stage
[2].
4. EHT generation is now started.
5.8Repair tips5. The OTC will un-blank the picture.
6. When you switch "off" the set, this is done in a controlled
5.8.1 Miscellaneousway via the POR signal [3].
Note: Standby is not directly achieved via the Standby line of
The relay you hear when you switch the set "on" (from Standby
the microprocessor, but indirectly via the HOP circuitry.
or via the mains switch), is from the degaussing circuitry. It is
not used for switching the Power Supply (as done in the MG-
chassis). |
ACEC
