Help! Nikon F4 with SB-600 speedlight won't fire

Please bear with me as I may be overlooking a basic mistake on my part, however my SB-600 when attached to my Nikon F4 via the hot shoe will not fire no matter the mode set on the camera. When connected, the speedlight kicks into TTL-BL mode, and I get the little red flash symbol in the viewfinder display. I can also fire the flash manually just fine, only firing the shutter on the camera will not trigger the flash. I'm dry firing it without film in the camera for testing. Am I missing something here?

I've used my SB-600 on my F4 a decent amount, so I know that this combo will work.

 

Just to check one big thing off the list-have you used other flashes on your F4 to confirm that the hotshoe actually works? This has "bit" me more than once on other cameras.

I agree with Ben. It's possible the the hot shoe not working because someone used a high voltage flash on it before.

A couple of things you might want to try:

1. Take a cotton swab (aka "Q-Tip) wetted with isopropyl alcohol and clean all of the flash contacts on the hot shoe, including the ground (springy bit under the edges of the flash shoe mount).
   
2. Pop off the viewfinder and do the same for both the gold contacts on the body and the pins on the underside of the DP-20 viewfinder.
   

It's possible the the hot shoe not working because someone used a high voltage flash on it before.

I would suspect the chance of this is pretty remote. The F4 flash sync system is good for up to 250v if my memory is correct.

 

Good luck.

(I miss my F4 ... fond memories of shooting with it)

I'm dry firing it without film in the camera for testing. Am I missing something here?

A long shot, but do you have the ISO set manually (i.e. not set to "DX")?

 

Suspect if you have it set to DX the SB-600 may not fire when in TTL-BL mode if it doesn't know the ISO.

A couple of things you might want to try:

1. Take a cotton swab (aka "Q-Tip) wetted with isopropyl alcohol and clean all of the flash contacts on the hot shoe, including the ground (springy bit under the edges of the flash shoe mount).
   
2. Pop off the viewfinder and do the same for both the gold contacts on the body and the pins on the underside of the DP-20 viewfinder.
   

 

I would suspect the chance of this is pretty remote. The F4 flash sync system is good for up to 250v if my memory is correct.

 

Good luck.

(I miss my F4 ... fond memories of shooting with it)

 

Almost all Nikon's currently on the market is rated for 250V but then there are many old flashes that has sync voltage higher than that.

I've been selling film SLR's for a while and I always check the flash sync. I would say around 25% have non working contacts. Pentax cameras seem the worst, particularly the MX which typically has non working hot shoe and X terminals, but a working M terminal. Nikons are usually OK although I just tried a Nikkormat and both terminals are dead, I guess some are more vulnerable to high synch voltages than others.

Thanks for the replies everyone. I went through and inspected + cleaned the contacts on the hot shoe, the flash, and those in between the viewfinder and the body. They all looked very clean and my alcohol swab didnt take much shmoo off. Oddly though, while in standby mode the flash will wake up when the shutter button is half depressed, so it seems that some of the pins are working correctly. Michael, yes I double checked that the iso was set. John, have you been testing with a multimeter or just with a known working flash? I do not have another flash to test with unfortunately so I can't tell if its the camera or the flash that's giving me trouble. I love this camera and I'm hoping it turns out to be something trivial.

Hopefully you have a bad flash. The fact that it wakes up from standby mode and you are getting a flash ready indication in the viewfinder indicates that at least the F4 is communicating with the flash.

 

I have a less than favorable opinion of the SB-600. The one I used to own failed twice. Official Nikon Canada unit. It would randomly not fire (on a D200), eventually to the point that it would not trigger more often than it would successfully fire. Sent it in to Nikon Canada and they repaired it. Forget what they replaced but it was a major repair. Used the repaired flash (now on a D7000) for probably less than 6 months after it was returned to me when it failed again, this time completely. Would not fire even off camera with the test button. Tossed the damn thing in the garbage and bought a new SB-700.

I use a known working flashgun for testing - trying to do it with a multimeter, you need three hands and a bit of luck. The flashgun has a PC connecting cable for checking the flash socket on the camera too. It's best to check the synch voltage with a multimeter first, as mentioned, some old flashguns can run to 300 volts, which is why cameras were fitted with covers over the hotshoe and flash terminal - the high voltage could be conducted from shoe to terminal via the internal wiring of the camera, giving anyone who accidentally touched them a nasty surprise.

 

Note that measuring with a multimeter will depress the synch voltage to a degree, giving a false low reading, but it's better than nothing.

So I managed to get a hold of a D70 body and the flash fires just fine when connected via the hotshoe. This isn't really good news though, as it means that my F4 body is problematic. Also when I connect a zoom lens to the F4 and change the zoom the Sb600 changes its zoom accordingly, so most of the contacts work correctly. I guess it might be that something in the shutter-body-finder-hotshoe path is fried, in which case I'm really not sure where to go from here. Edited June 8, 2020 by Julesf

Upon very close inspection with a macro lens I found some pretty not-great looking wear around the sync contact on the body. It almost looks like the plastic's been melted just below the contact. This is a used camera and its honestly so small I didn't catch it when I bought the thing. This seems like it points to someone using a high voltage flash on it previously.

 

Ha! I figured it out. It seems that the rut that was carved out by the melting on the sync pin meant that the mating pin on the dp-20 finder wasn't being depressed into the correct position and the two weren't making contact. I carefully cut out a piece of aluminum foil and placed it on the contact and voila! Thanks for all the help and interest everyone!