Yep, Authorized Photo Service in Morton Grove are fair and good! I have been using them for 20+ years. On a SB-800, you probably need a new flash tube. I have had two replaced on two different strobes.
I have a D300 there right now for cleaning and to be used as a back up camera. I will pick up a another D7200 at Xmas when the price, hopefully, drops $200 as it did last Xmas.
Go to Authorized Photo.

How come no one is talking about HDR Photography? Once you see what kind of images you get when you combine 7 exposures, you will will never go back to a single image in real estate photography. I do not know about other cameras, but the D7200 makes it outrageously easy!

Hopefully, I am replying to the person about the flash question. First it must be said that there are many ways to get the result you want. I know what I know and it works. Shoot these flash exposures in manual. Never go above f5.6 It is too much work for the flash. I typically work at f4 or more open. camera set at 1/60. if you sync at less go to rear sync flash. Use your Iso depending on the conditions. bright envorironment, maybe start at 400 or less. dark environment, easily go to 1600 iso. I use a D7200 and there is no noise there. With flash I work with in 15 ft. Ok to use modifiers there. beyond 15ft. take off the modifiers. I only use my Nikon flash on "A." if you need a slight more light, click the + button and it raises the power by a 1/3 each time. To some up:
camera manual
"play" with iso
Flash at "A"
use rear sync below 1/60
I have a ton of samples at www.delottphoto.com
To me, the difference between a pro and amateur, the pro uses his flash.

I am a successful professional photographer. However, I do not do sports or wild life. That said the D7200 Nikon is the best camera value. I use the nikon 50mm for my studio head shots, the Sigma 85mm f1.4 lens, and the the Sigma "brick" 18- 35mm f1.8. Together with LR and Nik software at this time, you will have the very best images! www.delottphoto.com