IBM 6500-V20 Maintenance Manual - Page 258

Power Supply Operational Check ATTENTION ATTENTION This procedure shows you how to use power supply tester 10R4059, to quickly and safely monitor the output voltages of the printer power supply from outside the card cage. You will be able to turn on and off the +48 volt and +8.5 volt outputs at the tester's remote Monitor Block. To check the power supply you need a DC voltmeter with an input impedance greater than 20,000 ohms per volt and capable of measuring 55 volts DC. To measure +5 volt output, the voltmeter must have a low voltage range (10 volts). The power supply tester is for intermittent monitoring of power supply voltages. Do not hold down the push button on the Monitor Block for more than five minutes at a time. To prevent overheating the Load Block, for each minute you hold down the push button on the Monitor Block, wait at least two minutes with the push button released. (There is no time limit to how long the Load Block can be attached to the power supply, just to how long you should hold down the push button.) 1. Prepare the printer for maintenance (page 313). 2. Cabinet Model: Remove the paper guide assembly (page 348). Pedestal Model: Remove the top cover assembly (page 327). To prevent electrostatic damage to electronic components, wear a grounded static wrist strap when you work around the circuit boards. 3. Put on a static wrist strap and ground the lead to an unpainted part of the printer frame. Touch the printer frame with the hand wearing the wrist strap before you touch the controller board or power supply board. 4. Disconnect power supply cable connector P101 from either the power stacker power cable or connector J101 on the controller board. (Figure 12.) 5. Plug power supply connector P101 into the 12-pin connector on the power supply tester Load Block, as shown in Figure 12. Note the position of Pin 1 relative to the Load Block. 6. Position the tester Monitor Block outside of the printer with the rubber feet resting on a flat surface. (If you are working on a cabinet model, you can close the top cover and use that as the flat surface.) 258