SB-600 not talking to D50

have you tried resetting to default settings?

perhaps it's sensing that the diffuser is out. because if the diffuser is out, the flash will not zoom (at least it was like this with the SB-80DX)

flash bulb could be burnt out...if it doesn't fire when when you push test, that's my guess as to the problem. Another possibility (although unlikely) is a loose connection in the flash.

problem in zoom motter unit repair it

try to clean the hot shoe of the camera &try the flash to use on anther camera and see problem is in flash or camera

Definately a settings problem. The camera will only syncronize on one specific speed. Youe best bet is to use auto. For manual, you'll have to set the shutter speed at the sync speed.

Flash Sync Speed

up to 1/250 X-Sync Speed

up to 1/8000 FP High Speed Sync

Red-eye reduction
Red-eye reduction with slow sync
Rear-curtain sync
Slow sync
Front-curtain sync (normal) Flash Sync Modes

1) i-TTL: TTL flash control by 1,005-pixel RGB sensor, built-in flash, SB-800, SB-600, SB-400: i-TTL balanced fill-flash and standard i-TTL flash
2) AA (Auto Aperture-type) flash: Available with SB-800 used with CPU lens
3) Non-TTL Auto: Available with Speedlights such as SB-800, 28, 27, and 22S
4) Range-priority manual flash; available with SB-800 Flash Control

Series of images is the KEY. If the Power you set the SB-600 is HIGH it will take a LONGER time to recycle than the SB-800. If you try to take a photo before the SB-600 is ready you will get a dark image. The randomness you get is due to the time between shots. In general try to run remote flashes at a lower power so they recycle faster.

I like the SB-800 because it can take 5 cells. 5 cells can really make a difference in the recycle time (faster) The SB-600 only takes 4 cells so it is slower.

sb-600/800 make a distinct motor-spinning noise when zooming, this is normal. Any grinding/clicking noises are not normal.

I had the same issue. The flash is set to go off, the camera assumes it went off, (as the record metadata shows) but it doen't go off at all, and the piture is underexposed.

I bought the 100 page repair manual, which is ONLY a dissassemble/reassemble manual with NO diagnostics. (Got it on ebay) So I was atleast able to get to the capacitor and flash bulb. I saw 300V across the capacitor leads, and the same 300Volts across the flash bulb leads. SO I am assuming that there is a transistor or relay that drops to ground to fire the flash that isn't working, or the electronic signal to drive that isn't working.

It seems most people replace the entire flash circuit board(which is near the capacitor under the left hand side). But it seems Nikon only sells parts to it certified repair facilities.

Ugh.... Looks like I'm buying a SB-600, as this is the cheepest solution. Too bad, because the on-board flash is more than decent. I hope the SB-600 thrills me enough to change my mood. :)

Switch camera off and remove batteries. Leave for half an hour. Re insert batteries switch on set to flask and hold to ear. Can hear a whistling [This is the Flash charging up] If you cannot -assume the flash unit has failed. Now go to the Manual - A full version is in a PDF file on the Disc. Check through that you are doing every thing correctly. If still no lick Nikon customer support will advise your next move. The likely hood will be that if the camera is over a year old they may offer a discount on a replacement. A repair is not likely or very pricey.