Hi I can appreciate this may be an old SDS - Black and Decker SDS KD1001K Type1. Problem I have is that this unit is fine when one pneumatic hammering operation is active but when switched to both hammering and drilling the unit does turn but as soon as I apply a little pressure (not a lot) the rotation just does not want to know. Obviously something is not engaging or possibly a shear pin in the unit. Not sure. Any help would be appreciated along with thoughts. Every topic I tend to read is reference issues with hammering but this isn't the case. Hammering is good, rotation is not really happening. Regards Sean
Best advice I can offer is find your local B&D service centre. http://service.blackanddecker.co.uk/BD/GB/en-GB/AgentLocator/SearchAgentLocators
Clutch. Check forward/reverse button is correctly engaged, and torque setting is not between slots. Also speed setting.(Assuming you have all those settings!)
End of the day, what you spend on repairing it,if repairable could go towards a new drill. http://www.screwfix.com/p/bosch-gbh-2000-corded-sds-plus-drill-240v/87453