Mains jigsaws.

[TRITON]

ebay search ‘bosch battery converter’.

That could be just something im after. Bought Bosch, wish i'd bought Makita.
Bosch make about 6 bare tools for 18v, Makita have about 60.

 

[JobandKnock]

Circuit board? Aren’t they just a motor with mechanical bits attached?

Not these days - the circuit board contains the speed controller,si it is probably that which has failed

The reliability I've had with Bosch tools hasn't been bad over the last 4 decades; a previous Bosch corded jigsaw (a GST135BCE) was in use as my primary jigger from 2005 until partly replaced by a Makita cordless in about 2010 and finally fully supplanted by a Mafell P1cc in 2015, since which time it became a "loaner". 2 years ago it was sold to a colleague (for parts price) who needed a cheap 110v joggers his cordless couldn't hack it on the job he was on. It is still in regular use. The GST150BCE and GST160BCE jigsaws I have a "fleet" saws (I.e anyone whi works for us and needs can have a go - gotta keep the job rolling) are now 5 and 4 years old respectively. For medium to heavy trade use I don't think that's too bad TBH

 

[NormanB]

Circuit board? Aren’t they just a motor with mechanical bits attached?

It probably effects cutting speed by pulse width modulation (PWM).