Can you use the Vivitar 2600D flash on a Nikon D3100 dslr?

I recently purchased a Nikon D3100 DSLR, would it be ok to use a Vivitar 2600D flash which I bought years back but still functions like new.

Yes, you can. You have to shoot in manual mode to make it work right, auto modes will not know there's a flash present and your exposures would be off.

I'd be wary.

According to this site http://www.botzilla.com/photo/strobeVolts.html the Vivitar 2600 has a trigger voltage of 148 Volts. That's fine for film cameras but digital cameras tend to emit magic blue smoke with a trigger voltage above 12V.

Check the documentation or online if the 2600D has a substantially lower Voltage than the 2600.

You could isolate the voltage by using a safe sync on the hotshoe ($50: http://www.bhphotovideo.com/...oe_to.html ), or a sync cable connection from the camera to the flash, or you could get even fancier with an infrared or radio remote trigger solution, just don't attach the flash directly to the hotshoe unless you sure it's okay.

Or invest in a modern flash. The Nikon SB-400 is pretty basic but it does give you automatic (i-TTL) metering and a bounce head etc. For just $120.