Saturn Model 1 Access Led not working

Just picked up a Saturn Model 1 and everything on it works fine except the red access led. I took it apart and tested the led and it lights up fine when I put 3V on it. I was able to confirm the ribbon cable from the controller pcb to the mobo is getting a connection so that ribbon cable isn't a problem.

I assume it is similar to the model 2 and R48 is the resistor connected to the access led. I have no idea where to go from here.

Any help would be appreciated.

 

Probably the motherboard isn't the original one for that unit. There were batches without the led and those motherboards do miss the parts to make the led blink even though the pinout is identical.

 

So there is a version of the Model 1 motherboard that is missing access light functionality? I wonder why? I'm guessing if it isn't the original motherboard then restoring functionality to the access light is probably impossible unless I hunt down a schematic. The bios for the system is 1.00a. I don't know if that helps to narrow it down at all.

 

When they started making units with the round buttons they had the access light removed but they kept using the older oval button boards until they depleted the stock. That's why there are boards without the access light circuit.

I remember it was something simple/idiotic like a transistor and a resistor missing. But I don't remember the details. You can simply copy from another board.

 

Thank you very much for the info. Unfortunately I don't have an extra board to harvest parts from and even if I figured out what was missing I will probably never be able to figure out the values. I think I may need to abandon this project.

 

Thanks for your help on this but I gave up and returned the system for store credit. The model 1 I bought was in rough shape to begin with (cracked case, missing screws) so the access light not working wasn't my only problem with it.