How much money does it pay to put into it? It is a gimmick that nobody else bothered to copy.
I may have the wrong end of this, but are you saying that a speed controller is "a gimmick that nobody else bothered to copy"
? If so, I'd have to disagree, as almost every router I've bought new since the mid-1980s has been variable speed.....
This router I have has done nearly no work in the 20 years I have had it so now maybe I can sell it for a more modern one or use it in a table like Ron Fox suggested in his report on it.
Well, providing you don't want to run large diameter bits (e.g. panel raisers or large diameter profile bits) and are content to stick with bits of say 22mm (7/8in) or smaller then the router is certainly still useable, especially for tasks such as mortising, template routing, grooving, cutting housings (dados), etc. The choice is yours.
I have found a parts listing for your router - the distributor in the UK is Spare Tool Parts UK and the listing page is here
. Looking at the diagram I can see similarities to the design of the Elu MOF177e (later deWalt DW625 - Elu were the first router maker to produce heavy duty VS plunge routers in about 1979). One thing which struck me is that the RE601 uses a magnetic core (item #36) which seems to be similar to what Elu used to call the "wheel" - a small disc which contains a piece of metal on one side and is used by the router to monitor the spindle speed. In the case of the Elu (and later DW) these can occasionally come loose or detach and cause the variable speed to stop working. The fix is simply to reattach and glue the item in place at the top of the router armature shaft with a spot of Loctite. It may be worth looking into this
BTW I'd be happy to track down the distributors for AEG tools here if you'd like