My dewalt 788 scroll saw will not speed up. i had it for several years but never used it but when i did try to use it ,it operates very slow.

Item 61
https://www.fix.com/models/scroll-saw/dewalt/id773687/dw788-type%202/section6573527/page-b

This sounds like the motor may have an issue or the speed control trigger switch.

Check out the brushes for contact on commutator.

Blowing fuses is not caused by brushes unless there is a huge spark show going on and if that is the case your armature will be trashed as well - the electronic module in that saw is notorious for failure and that is where I would start

First: if there is looseness in the table, it is dangerous. So I would check all the parts for wear. If, for instance, a knob worked loose, the bolt could have worn (via vibrating) the bracket, resulting in you being unable to tighten it correctly. Occasionally I take mine all apart and check it all over for just that reason. I also check all the knobs just before use to make sure they are all tight. Here is a web page talking about Dewalt scroll saw problems and solutions http://www.scrollsaws.com/SawReviews/DewltTuneUp.htm

I have no idea most folks throw them away.

look at the tag again and please add which type there are 4 listed then click this link for the info you want http://servicenet.dewalt.com/Products/Detail/DW788

Part is $84.00 Are the operators crowding the tool, blades sharp? Scroll saws do not cut quickly.
https://www.ereplacementparts.com/dewalt-dw788-type-scroll-saw-parts-c-1009_2631_2632.html

might be pushing it to fast? or a bad outlet/plug?

CHECK FOR ANY BREAKS OR WEAR IN CORD , IF NONE IT MAY BE THE CARBON BRUSHES ARE WORN OUT .