What’s this circuit i found inside my CD player?

[sergimm]

I just purchased an old Marantz CD-67 MKII SE, and when I opened to check the state of the internals, I found a custom circuit that seems to connect to the frontal panel buttons. What I presume is/was its power source cable has been cut.

The CD player works perfectly otherwise, but I’m curious about that hack. See photos attached.

 

[Mark Johnson]

Those four black things look like relays to me

 

[billshurv]

It was most likely a cabled remote control as the board had 4 relays on connecting to the controls related to playing CDs. Maybe used it as an alarm clock?

 

[sergimm]

That makes sense. I also thought maybe a remote control of some kind...still weird since this player has a remote control. The alarm clock scenario seems much more feasible. Thanks!

 

[JMFahey]

Relay contacts are most probably just in parallel with front panel buttons.
Shortest simplest path solution.
What activates the relay coils?

 

[billshurv]

still weird since this player has a remote control.

Quite. I did wonder about some home automation setup, but you'd still need to turn it on and off. And for a bar or restaurant you'd want a changer.

Relay contacts are most probably just in parallel with front panel buttons.
Shortest simplest path solution.
What activates the relay coils?

That is the bit that was cut off so we don't know!

 

[HarryY]

The EDR201A1200 is a relay so I would say some form of wired remote.