[Help needed for] Tapping into existing infrared receiver (of old Technics amplifier)

I have an old Technics amplifier that I would like to make “smart” by tapping into the infrared signal - similar to how it’s being discussed here. I have followed the many tutorials and instructions for setting up a remote receiver, but I’m failing to get any kind of signal to be dumped in the log.
(For now I’m only interested in getting the ESP32 going as a receiver.)

I suspect that the problem is on the hardware / wiring side, but am not sure what I need to do.

Questions

  • Does anyone have inputs on my specific setup, what I need to fix?
  • Is there more documentation somewhere on what kind of input (Voltage range, etc.) the remote receiver component expects? I wasn’t able to find much on it.

Thanks for any help!

What I have done so far:

Hardware

Components

Wiring
See below a simplified schematic of the relevant circuit in the receiver. The parts added by me are marked yellow. The voltages in red are indicated like this in the service manual.

=> When I measure the signal coming in at GPIO33 simply using a multimeter, I can see that it sits at around 0.66V as indicated also in the original schematic. When an Infrared signal comes in, I can briefly see it going down to about 0.57V.
=> My guess is that this is not an appropriate voltage range for the remote receiver component to pick it up?
=> Could I simply connect on the other side of the resistor, or would the voltage there be too high for the ESP32 to handle (6V vs 3V)?

Software

This is my YAML configuration. I’ve tried it with and without inverted and mode. When using inverted: true I get a yellow hint in the log indicating that I might be using it wrong.

=> My guess is that the remote receiver component thinks that 0.6V is low when actually it reflects the high state in the original circuit?

substitutions:
  name: esphome-web-be2a30
  friendly_name: Dev Board 1

esphome:
  name: ${name}
  friendly_name: ${friendly_name}
  name_add_mac_suffix: false
  project:
    name: esphome.web
    version: '1.0'

esp32:
  board: esp32dev
  framework:
    type: arduino

# Enable logging
logger:
  level: VERBOSE

# Enable Home Assistant API
api:

# Allow Over-The-Air updates
ota:

wifi:
  # Set up a wifi access point
  ap: {}

# To have a "next url" for improv serial
web_server:


## IR Receiver
remote_receiver:
  pin:
    number: GPIO33
    inverted: true
    mode:
      input: true
      pullup: true
  dump: all

I’d be interested to find out if you are successful as I have an SU-A800 which I’m using a broadlink RM3 mini to control. It would be great to simply stick an ESP in there and control it directly.

Note the RM3 can actually send a distinct ON and OFF rather than a toggle. I got the codes for that from my SU-A707 amp. Looks like they must all use the same controller.

Wouldn’t it be easier to add a separate ir-receiver just for esphome? They cost pennies…