Retrofitting a 12V trigger in for Yamaha RX-V2400 receiver

Just wondering while trying to parse the schematics of my Yamaha RX-V2400 whether it would be possible to retrofit a 12V trigger input? It does not have one. Appreantly there are some variants of this model that came with a trigger input which makes me hopeful
If possible a solution that operates with standby power on/off vs. full.

I attached the schematics
 

Attachments

thanks. This is great. I could see whether I can put the device inside receiver. Would need to find a 24V source in there to power the device. Or keep it outside and wire to the button inside.

My assumption the player has 12VDC on the trigger while player is on. So, this device would trigger during the transitions?
 
I got all the HW and was able to connect a cable across the standby switch.
I wired the 12V trigger from my external device the actuate input Screw terminal 2 and 3.
Got a 24VDC power supply.

My question: How to wire the switch cable? I need start pulse and end pulse. Do I wire in parallel start end pulse?
 
This solution worked great until very recently. The module is starting to oscillating on occasion. So far, I could not find the root cause. It does that without a trigger. It happens mostly in the morning. Unplugging trigger (although source device did not trigger) cable doesn't stop it.
Unplugging trigger module power supply will stop it. But as soon as I plug power back in oscillation continuous.
Power supply shows 28 VDC. Any chance the power supply could be an issue?
 
Try the below circuit instead:
When the player is powered on, its 12V trigger will turn on both relays, the top relay will turn off once the capacitor is fully charged, that will provide a momentary pulse to turn on the RX-V2400.
When you power off the player, the relay on the bottom will turned off and connect the capacitor across the top relay coil and turn it on again until the capacitor fully discharged. That will provide anther momentary pulse to turn the RX-V2400 back to standby.

Screenshot 2023-05-01 at 10-34-23 Free Online Schematic and Diagramming Tool DigiKey Electronics.png


2 - 12V Relay, coil resistance 720Ω or higher.
2 - 1N400x diode
1 - 470uF capacitor ( use different value to adjust pulse timing )

Above circuit does not require external power supply, it utilize the 12V trigger from the player to operate.
 
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btw. the RDL ST-LCR3 asks for a GROUND-REFERENCED power (24VDC).
I wired the 12V trigger from my external device the actuate input Screw terminal 2 and 3.
Got a 24VDC power supply.
How you get the 24VDC power supply from? If the 24VDC power supply is external (i.e. wall wart / power adapter), the negative of the power supply should be connected to the 12V trigger negative, that's the GROUND-REFERENCED. So the screw terminal #2 should connected to screw terminal #11 on the ST-LCR3.
Screenshot 2023-05-04 at 22-59-24 st-lcr3.jpg (JPEG Image 800 × 600 pixels) — Scaled (80%).png

This solution worked great until very recently. The module is starting to oscillating on occasion.
The strange thing: my issue only happens in the morning.
Perhaps some RF interference from the power supply, that's why I suggest try a ferrite bead on the power supply cable. Don't know if it helps, but i think it worth a try.

https://electronics.stackexchange.c...he-purpose-of-the-ferrite-bead-on-dc-adaptors
 
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