I think you cannot easily purchase a new PCB. This PCB is designed for your shaver and is not used in any other appliance.
Maybe some online shops can sell a PCB, but I do not think you will find such shops.
Contacting a PHILIPS Service Centre may be useful but maybe the repair price will be more than the price of a new shaver.
Now your options are:
1. Have the PCB replaced by a PHILIPS Service Centre.
2. Find a really good professional repair specialist to have your old PCB fixed.
3. Do something to charge the batteries without using the shaver's charger PCB.
Maybe solder in some holders for regular AA batteries and swap/recharge them outside the shaver in a regular charge.
Or I have seen a solar power mod for shaver where a solar panel was soldered to the batteries.
You can also design a new charger for batteries or make a connection for outside charger but it may be difficult.