Testing The New Power Supply - DYNACO PAT-5 Assembly Manual

Testing the New Power Supply

Safety Warnings:
 Clean-up and make sure that no tools are inside the preamp. You're about to
power it on to test the output voltages. Remember to be safe, as potentially lethal
voltages will be present in the next step.
Re-installing the power supply is a lot of work. It's probably a good idea to test the
supply before you re-install it. Follow these steps:
1. Make sure that the power cord is unplugged.
2. Fold a piece of 8.5"x11" paper in a U-shape around the bottom and sides of the
power supply. The idea is to form a temporary insulator that will keep the PCB
from making electrical contact where it should not.
3. Set the combination of the power supply and paper temporary insulator into the
chassis, close to its normal position.
4. Look at the arrangement to make sure that nothing from the power supply can
contact the chassis. If necessary, add a second piece of paper.
Be Careful. The next step makes 120Volt AC accessible inside the unit.
5. Plug in the power cord and turn on the power switch. Stand back and look for a
minute. There should be no excitement. Pull the plug immediately if you see
evidence of smoke or fire. If all is calm after 1 minute, go on to the next step.
6. Measure the DC voltage from any of the P15 terminals to the GND terminals. It
should be 15+/-1 Volts.
7. Measure the DC voltage from any of the N15 terminals to the GND terminals. It
should be -15+/-1 Volts.
Pull the plug from the AC wall socket (mains). If the voltages were correct, go on to the
next section. If the voltages were not correct, then examine your board for missed solder
joints, backwards diodes, missing components, backwards capacitors, swapped
regulators, and the like. There is no point in going on until the power supply is
functioning correctly. If you get stuck, send email to dan@updatemydynaco.com.
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