Solid State Guitar Amp Forum | DIY Guitar Amplifiers

Hey guys, just wondering if anyone could point me in the right direction of ways to do pretty basic tests on gear? Specifically whether something's mains input is working correctly? I've got an old Alesis compressor which uses an unusual mini jack style plug w/ DC, and compatible supplies are hard to find. I've got a power supply for it and also a noise gate from the same series which is also not working. Is there any straightforward way of using a multimeter to see if there's a break in the circuit that deals with taking mains power? I imagine this could be more straightforward on the power supply then either of the units! Thanks for the help!

Isn't there a label on the supply module telling its outputs?  And if so, if you cannot measure said voltages directly on the adaptor plug, then plug it into the unit and measure on the power jack pins inside.

Thanks for the help! It's been so long since I've really used one that I forgot that they can be used with an active circuit (of non-lethal power ratings that also won't destroy the thing obviously haha). The supply was dead so got a new one, simple enough. All the wiring & fuse seemed fine, so I can only assume that the actual transformer had died maybe? Way above my level of understanding to mess with that anyway.