Panasonic CT-32SX31CE Service Manual

Also see for CT-32SX31E: Operating instructions Service manual

Panasonic CT-32SX31CE Service Manual Manual pdf 5 page image

- 5 -Service Notes (Continued)IMPORTANT: To protect against possible damage tothe solid state devices due to arcing or staticdischarge, make certain that all ground wires and CTRDAG wire are securely connected.CAUTION: The power supply circuit is above earthground and the chassis cannot be polarized. Use anisolation transformer when servicing the Receiver toavoid damage to the test equipment or to the chassis.Connect the test equipment to the proper ground () or( ) when servicing, or incorrect voltages will bemeasured.WARNING: This Receiver has been designed to meetor exceed applicable safety and X-ray radiationprotection as specified by government agencies andindependent testing laboratories.To maintain original product safety design standardsrelative to X-ray radiation and shock and fire hazard,parts indicated with the symbol on the schematicmust be replaced with identical parts. Order parts fromthe manufacturer’s parts center using the partsnumbers shown in this service manual, or provide thechassis number and the part reference number.For optimum performance and reliability, all other partsshould be replaced with components ofidentical specification.Horizontal Oscillator Disable CircuitThis chassis employs a special circuit to protectagainst excessive high voltage and beam current. If, forany reason, the high voltage and beam current exceeda predetermined level this protective circuit activatesand detunes the horizontal oscillator that limits the highvoltage. The over-voltage protection circuit is notadjustable. However, if components indicated by thesymbol on the schematic in either the horizontalsweep system or the over-voltage protection circuititself are changed, the operation of the circuit shouldbe checked using the following procedure:Equipment needed to check the disabled circuit:1. DC Ammeter2. High Voltage Meter (0- 50kV electrostatic)3. Variac or Isolation Transformer4. HHS Jig (See Fig. 2)Figure 2. HHS JigPreparation1. Connect Receiver to AC 120 Volts. Do not turn ON.2. Connect HIGH VOLTAGE meter to 2nd anode(H.V. button).Note:Use cold ground( ) fornegative lead.3. Connect the ammeter serial from the flyback anodelead to the picture tube anode socket.4. Prepare HHS jig to be connected between TPD50and TPD51 as shown in Fig. 2.Procedure:1. Open Connector A17.2. Turn power ON and Apply a monoscope pattern.3. Set current within 50-100μΑ by changing thepicture and bright controls.4. Turn power OFF.5. Connect HHS jig between TPD50 and TPD51 (VRshould be turn fully clockwise).6. Turn power on.7. Turn slowly the variable resistor to increase thecurrent until the horizontal sync frequency abruptlyincreases indicating that the horizontal frequency isjust beginning to pull out of sync. Maintain thecurrent within 50-100μΑ by changing the pictureand bright controls8. Observe the High Voltage meter. HIGH VOLTAGEshould read less than 40.2kV.9. Turn power OFF, Remove HHS jig, HV meter,ammeter and connect A17 connector.10. Turn Power ON. Reset Picture and Brightnesscontrols. Confirm B+ 140V±1.5V with 120V ACapplied.11.IF HIGH VOLTAGE IS NOT WITHIN THESPECIFIED LIMIT THE CAUSE MUST BEDETERMINED BEFORE THE RECEIVER ISRETURNED TO THE OWNER.TPD50 TPD51100Ω 1KΩ