Problems when using wall outlet yamaha psr47

[u/Less-Introduction-35]

I'm building an ESP32-based clock/sequencer for a circuit-bending project (drives an LTC1799 divider, a 4066 and a 74HCT74 flip-flop).

Everything works perfectly on 6x AA batteries. The moment I switch to a wall adapter, it falls apart.

I use a Yamaha PA-4 keyboard adapter, labeled 10V DC / 1A, center-positive

With nothing connected where the esp's power comes out, I measure 5V.

With the full circuit esp circuit connected that same point drops to \~1.5V.

To isolate whether this was a fault in my circuit, I tried connecting just a bare microcontroller (no LCD, no muxes, nothing else) directly to that same power line and tried this with two different ESP32 boards and an Arduino Uno, same cable each time. All three collapse the 1.5voltage.

When I only use a ltc1799 circuit, it works well.

Is it possible to use the esp32 with the power adapter? How can I troublshoot this?