Tomorrow i will try my F3AF and AS-17 with this AF-light.
F-501 can lock focus with this one - even in light conditions when focussing normally is not possible.
Never the less i will modify the SCA for use with the F-501, using a SCA300A cable, remove the cable and add a small switch instead.
The AS-17 is a TTL flash adapter for the Nikon F3 and has all the same number of contacts as the hotshoe of the F-501:
Just as with the F-501 the flash-ready LED lights up in the view finder of the F3, but autofocus help light doesn't work.
I dont know which signal of the hotshoe is missing and what modification has to be done.
I did some soldering last evening and modified a defect SCA 300A cable with the cable bridge and a small switch.
Now i can use old Nikon AF camera like F-501 or F90x with a AF help light without the need to add a flash light.
This is what it looks like:
The switch is needed to avoid battery drain when not in use. Its just some milliamps, but with the switch set off, the flash ready signal is turned off and battery remains full.