{"id":3301,"date":"2021-05-10T13:03:30","date_gmt":"2021-05-10T20:03:30","guid":{"rendered":"https:\/\/www.rbdinstruments.com\/blog\/?p=3301"},"modified":"2021-05-10T13:03:34","modified_gmt":"2021-05-10T20:03:34","slug":"testing-the-fuses-on-the-card-rack-power-supply-outputs","status":"publish","type":"post","link":"https:\/\/www.rbdinstruments.com\/blog\/testing-the-fuses-on-the-card-rack-power-supply-outputs\/","title":{"rendered":"Testing the fuses on the Card Rack power supply outputs"},"content":{"rendered":"\n

The fuse strip located near the hinge on the OEM supply door routes the +5, +15, and -15 voltages from the OEM supply to the card rack unit motherboards.<\/p>\n\n\n\n

Each card rack unit has a dedicated section of fuse strip\nand specific fuse values.<\/p>\n\n\n\n

When troubleshooting problems with card rack units it may be necessary to test the fuses in the fuse strip. With the card rack power OFF you can visually inspect each fuse to see if any of them look like they are blown. You can also use an ohmmeter to measure the resistance of the fuses (typically one ohm or less). In some cases it is helpful to measure the actual voltage on the fuses.\u00a0It is possible that a fuse that looks good is actually blown.\u00a0Or the voltage on the fuse may be loading down on the output side.<\/p>\n\n\n\n

Since the +5, +15, and -15V OEM supply outputs are floating with respect to ground, you need to reference your meter to the correct place in order to measure the voltage. The card rack power needs to be ON when measuring the voltages on both sides of the fuses. The voltage should be very close to the same value on both sides of the fuses. One side is voltage in, the other side is voltage out to the card rack unit.<\/p>\n\n\n\n

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