Philips EM3E, Service Manual, Page: 32 / 120

Service Modes, Error Codes and Fault Finding GB 32 EM3E 5.
– Replace FET 7504 and zener 6505.
– Remove the SSB panel.
– Short B and E of TS7529, in order to put the Main
Supply in ‘on’-mode (TS7529 is blocking then).
Caution: To prevent that this will damage R3403
and TS7443, first disable the HW-protection of
the deflection circuit. Therefor short circuit C2642
on the LSP (diagram A4)
– Attach a load of 500
W
to VBAT capacitor C2515 (the
supply can not work without a minimum load).
– Use a variac, and slowly increase the VMAINS.
Measure over sensing resistors R3514//15 if a nice
sawtooth voltage becomes available.
– Also measure the VBAT . This may never exceed
+141 V. If it does, there is something wrong in the
feedback circuitry (e.g. regulator 7506).
• Note: Be careful when measuring on the gate of FET
TS7504. This circuitry is very high-ohmic and can easily
be damaged (first connect ground to measuring
equipment, than measure the gate).
5.8.6 Standby Supply
The simplest way is to replace the components of the
Standby Supply with repair kit 3122 785 90320.
5.8.7 Line Deflection
The simplest way is to replace the components of the Line
Deflection circuitry with repair kit 3122 785 90330.
5.8.8 Frame Deflection
Caution: When the Frame Deflection circuitry is suspected,
one must be careful. Because there is a DC-voltage on the
frame deflection, the beam current could damage the CRT
neck, leading to a defective CRT.
Best thing to do is:
1.
Interrupt the resistors 3403 and 3404 on the CRT panel
(diagram F), in order to remove the ‘filament’ voltage
from the tube (no beam current, so no chance of
destroying the CRT).
2. Interrupt resistor 3403 on the LSP (diagram A4) to
disable the ‘SUP-ENABLE’ line.
3. Measure with a multimeter, or better with a oscilloscope,
the functionality of the Frame stage.
4. After you’ve found the cause, exchange the defective
component (e.g. TDA8177), and re-solder the
interrupted resistors.
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