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GB 32
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5.
EM3E
Service Modes, Error Codes and Fault Finding
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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).
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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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