[train123]

I guess you need to begin with why you are troubleshooting an amp circuit. If the fuses are already blown, then you just need to check the output amp stages for a dead short using an ohm meter. If the fuses aren't gone, you can troubleshoot with a voltage meter. The proper way to power up a potentially shorted unit is with a variable AC supply and an Amp meter to measure the current draw. Slowly increase the AC supply while monitoring the current draw, if it draws excessively, then you've got a short. If you are carefully, you won't blow fuses during this test.

[helpful55]

I haven’t blown any fuses, I’m just planning ahead so I don’t blow any expensive fuses, a dollar’s a dollar. The amp circuit that I’m working with uses a fuse of 4A 110v, and is a slo-blo as the surge to charge the caps will blow fast acting fuses. Can you give me any ideas of how to initially test this audio amp that may potentially have a short problem? I don’t believe that I can go by resistance off the power plug terminals as the caps that are uncharged give a very low resistance reading. If the amp is 200 watt rms would a 100w incandescent in series work to determine if the circuit is shorted? And do I quickly disconnect if the bulb lights fully, or do I give it a few seconds before assuming a short with those caps? And will this still blow the fuse or can I defeat it for this test? (The cost of one fuse is OK if necessary for testing purposes). Thank you for any help.