PHILIPS 32PW9528/12
Manual de Servicio

Service Modes, Error Codes, and Fault Finding
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 OTC will store the error code in the error buffer of the NVM and, depending on the relevancy of the error bit, the set will either go into the protection mode or not. The following protections are implemented: � HFB (Horizontal Flyback): If the horizontal flyback is not present, this is detected via the HOP (HFB_XRAY_PROT). One status bit is set to "high". The error code is stored in the error buffer and the set will go into the protection mode. � XPR (X-ray protection): If the HFB pulses are too low (level detection), the HOP will detect this via the XPR-bit. The error will be logged in the error buffer and the set will go into protection mode. Note: Both errors will be logged as HFB-failure. 5.7.5 Hardware Related Protections Due to the architecture ("hot" deflection), some protections cannot be sensed by the microprocessor. Three of these protections will lead to a protection on set level (Standby mode and blinking LED), while another will only lead to a circuit protection. TV-set Protection The following fault conditions will lead to a "complete" set protection: � BRIDGECOIL protection: This is sensed via the "EW" signal going to the base of TS7652 (via R3495 and D6499). In a normal situation, the voltage on C2498 (diagram A4) is high and TS7652 is conducting. When bridge coil 5422 (diagram A3) is short circuited, the voltage on C2498 changes to low, which will block TS7652. In this case, also TS7641 will block and the voltage on 2642 will rise until TS7443 is forced in conduction. The "SUP-ENABLE" signal (in normal operating condition -20 V) is shorted now to ground level, which will force the Main Power Supply to Standby mode. � ARC protection: If there are "open" connections (e.g. bad solder joints) in the high-energy deflection circuitry, this can lead to damaging effects (read: fire). For that reason, the E/ W current is sensed (via 3479//3480). If this current becomes too high, the "thyristor" circuit (TS7653 and TS7654) is triggered. TS7442 is switched "on" and TS7443 is forced into conduction. . The "SUP-ENABLE" signal is shorted now to ground level, which will force the Main Power Supply to Standby mode. NON_VFB (No vertical Flyback) protection: If the frame stage generates no pulses, TS7641 will block. TS7443 is now switched "on", which will lead to Standby mode. Therefore, in normal operation condition, TS7641 and TS7652 are conducting, while TS7443 is blocked.
I2C BUS 1 5VCON RESET 106 8VCON 105 OTC 99 POR 104

EM5.1E

5.

EN 29

Take care not to touch the "hot" heatsink while disconnecting the SSB, despite the fact that the mains cord is out of the mains socket. There can still be an annoying rest-voltage on the heatsink for a short while. This, because the discharge resistors 3502 and 3503 (on the LSP between hot and cold part) are not stuffed for Europe. Instead, discharge resistors 3066 and 3057 on the Mains Switch panel are used, but because they are located before the Mains switch, they only discharge when this switch is "on". Advice: when you remove the SSB, disconnect the Mains cord, but keep the Mains Switch "on". Do not try to measure on the SSB side, which is facing the 'hot' heatsink. This is dangerous. Most service test points are guided to the 'tuner' side and are indicated by the 'service' printing. Where the circuitry was too "crowded" for service printing, you can find the correct location on the "test point overviews" in this manual. A very large part of the LSP is "hot", such as: � The primary part of the Standby Supply. � The whole Main supply (except for the secondary Audio supply). � And the complete deflection circuitry (so notice that the deflection coil is hot!). 5.8.2 Start-up Sequence

COLD

HOT

EHT-INFO

8V

5 START/STOP 17/39 HOP 29 START/STOP CUTOFF (from CRT panel) OUT

2

7141 5V 8V 7131

STBY SUPPLY

220 VAC

STANDBY low 7131/41 closed high 7131/41 open

3

MAIN SUPPLY
Vbat

SUP-ENABLE

+11D POR 7445

LINE DEFL. (BRIDGECOIL -PROT) (ARC-PROT) PROTSENSING FRAME DEFL (NON-VFB)
CL16532044_023.eps 140501

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Figure 5-4 Start-up circuitry The start up sequence differs from other sets (e.g. MG-sets or

Circuit Protection The following fault condition will lead to a "partly" set protection: � PROT1 (DC) protection: When a DC-voltage (positive or negative) is sensed on one of the loudspeaker outputs, the protection circuit (TS7704, 7705, 7706 and 7707 in diagram A6) will put the IC7700 in Standby mode (via tristate input pin 6). For more details, see chapter "Circuit Descriptions".

EM2E-sets, but is same as in EM3E-set): 1. When the set is switched "on", the 5 and 8 V lines ("+5V_CON" and "+8V_CON") of the standby power supply are activated. After the OTC senses them, the P will address the HOP via the I2C-bus, to start the drive [1]. Via the "SUP-ENABLE" signal, the Main Supply is switched "on" and will deliver the V_BAT to the Line deflection stage [2]. EHT generation is now started. The OTC will un-blank the picture. When you switch "off" the set, this is done in a controlled way via the POR signal [3].

2. 3.

5.8
5.8.1

Repair tips
Miscellaneous The relay you hear when you switch the set "on" (from Standby or via the mains switch), is from the degaussing circuitry. It is not used for switching the Power Supply (as done in the MGchassis).

4. 5. 6.

Note: Standby is not directly achieved via the Standby line of the microprocessor, but indirectly via the HOP circuitry.