Utica torque screwdriver

I purchased a Utica TS-100 torque screwdriver off of E-Bay. It should adjust up to100 in-lb. It has a recent calibration sticker, but the torque not even close to what it should be when tested with a beam type wrench of similar range. I believe it was calibrated for some special purpose and the adjustable feature not used.

I would like to know how to adjust it. I can use the beam wrench to get values close enough for my purposes. I have tried to increase the torque with the allen head set screw in the end. As it is turned in the torque does increase- but at about15 in-lb the screw is in so far it is running out of thread. I have to wonder if the original set screw was replaced with a shorter one.

Does anyone have any instructions or suggestions?

I found the info I needed at Uticatools.com. Not sure why it did not show up in the google searches I did before the post. I was correct in the screw in the end adjusting the torque- but incorrect that a longer setscrew is needed. Even when using the proper procedures it does not adjust. Looks like I will need to send it in. I suspect the spring was replaced or cut down to make it a particular value at the max setting.