Nikon F3 + SB-16A malfunction?

Hello,

I've shot a roll of Delta 100 with my F3 + SB-16A flash unit. I got very upset with the results. Only 10 pictures from 36. 8 of them were shot without a flash, and the rest 28 pictures were taken with a flash, only 2 of them "survived".
Everything seemed okay, flash did fire, I've set my camera to A (as shown in the manual) and did everything else by the books. The negatives are basically empty, only in some of the pictures there's a visible window somewhere in the background or something like that. So now I'm confused:
Is it a camera malfunction?
Flash malfunction?
Or I'm doing something wrong?

Thanks in advance

The first thing I would try is to look through the body(no lens) while pointing the flash & camera at a light colored wall. Try this setting the shutter speed manually.
You should see the wall as a bright area filling the film gate.

I'm not familiar with the flash/camera combination. So, is the flash supposed to set the shutter speed or just provide an indicator in the finder?
If the flash doesn't set this then the underexposure with just the window could very well be right because of too fast a shutter speed.

I don't recall the F3 having a ttl function setting the speed(been wrong before) just the indicator.

In A mode the flash would automatically set the shutter speed to X sync speed. However you must make sure that the ready light in the viewfinder light up. If not the flash would still fire but it won't set the shutter speed to X sync. Also the foot has a mechanism to engage with the ASA dial to transfer the ASA setting to the flash. If this doesn't work correctly the flash would get the wrong ASA and deliver wrong exposure. Third the flash has 2 light make sure both fire because the small flash only deliver about 10% of the light.