Voigtlander Bessa II 6X9

I have a Bessa II 6X9 with a Heliar mounted in a Compur Synchro shutter. The camer and lens are in fine shape, however the shutter has a weak main spring, so all speeds throughout the range are sluggish. I have been looking for someone who is able to service this shutter, and have not had much success. Any suggestions?

It's always worth having a look at this thread to see if one of the shops mentioned qualifies: https://www.photrio.com/forum/threads/repair-shops-in-and-out-of-business.210509

There's of course always the option of just accepting the situation, noting the slower shutter speeds and basing your exposure settings on the real speed instead of the nominal/indicated speed. This works well provided that the speeds are reasonably consistent.

If everything else about the camera is fine, I'd do what @koraks suggests and create a small chart to keep in my pocket of marked vs actual speed, then enjoy taking pics.