Looking for advice/ experience please

My first/front drop target was flakey registering drop.

So I removed and inspected inline drop PCB,
Nothing obvious so I decided to order a new PCB from our local distro
I quoted part # in manual 5206791-01
Distro indicated they had 1 left of part # quoted but ended up sending me 5206791-00

As per pics 6 pin vs 5 pin pro ?

Also as per pic in manual the drop ass'y has a part "23" Reflective opto isolater.
My bank ass'y does not have this installed, never has, not sure how it even worked from the start ?

Is anyone going under the hood of there LE or Premo able to see if there is this "Isolater" fitted ? I guess its just a piece of plastic ?

Anyone had to change the PCB before ?

Appreciate any help

Cheers,
Ando

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Problem solved

Correct PCB provided
Distributor kindly provided part #23 opto isolator at no charge.

All good now
METLE plays as it should, Awesome !