Nitecore HC35 replacement driver and MCPCB?

Hi, my buddy’s Nitecore HC35 is toast, both the MCPCB and driver are dead. I’ve emailed Nitecore and they only offer off-warranty repair for a fee, they won’t ship the driver/MCPCB.

I’m wondering if there could be say a Convoy (or any brand really) 22mm driver I could use for this? The light is a 4x LED, 3V LEDs. I’d put 519a in there (original LEDs are toast too). We don’t mind losing the USB charge.

Thank you!

Driver and mpcb diameter? Output voltage? Leds in series. In parallel?