dim bulb tester. put a incandescent bulb in series with the mains input to put a lower voltage on the power supply’s input. If it glows brightly, there’s probably a short in the psu.

#1: StormAudioISPEliteMk1;DSP5K2/5K2HC/D33x6/D2500;RoonRock/Tidal
RegaPlanar3/RB250/Carbon/NADPP2;SonyTCK850es;CaCXUHD;CaAzure651T;GoogleTV; FireTV4KMax;AppleTV4k;Virgin360/Philips 65OLED950;SonosArc
#2: 562v2;DSP5K;FireTV;SonyBDPS3700;CAAzure640T
Spare: 568.2mm (faulty);596s;DSP5000C;M60C;Explorer2;G68ADV;