I am still using a very old Yamaha P250 (probably 20 years old now) as my studio controller keyboard. These were very solid and built like tanks. It is a full 88-note weighted action and although there might be better actions now available I have been very happy with it. It has mod and pitch bend wheels and sockets for expression pedal as well as sustain etc. It also has built in and very powerful speakers which I rarely use but can be useful in certain situations. If I am recording a vocal harmony I can quickly turn on the speakers to remind me of notes and then turn them off when I am recording my vocal.

You could probably pick one of these up for a good price so long as you double check it has been well looked after.

Which keyboard is giving you some trouble? It does not sound like it is worth spending repair money on that might not work out.