Some info on unlocking can be found here. You can also find information in the Really Right Stuff catalog or website at this address.

Mine locked up twice and I was always able to unlock it using the above techniques.

Let us know if you managed to unlock it.
Good luck
Francois

Thanks! I'll check these out and hope they work!

Best,
Spencer

I mentioned the PC website in my first link  :D
So if your B1 needs repairs, contact them.

Francois

Hello,

I have read over the years that the B1 can lock-up. I never paid much attention since mine never had any troubles, until now. I was shooting the National Day parade here in Singapore and my tension knob locked in the open position. Does anyone know how to unlock it? It wont budge.

It had been working fine the few minutes before. I took my tripod down to move and when I went to set up again, it was locked.

Thanks in advance.

Regards,
Spencer

Download the PDF version of the RRS catalog. On page 8, you'll find a desciption of the procedure to unfreeze your BH. If it fails to unlock it, you may have a more serious problem with it.

HTH,
Francois

Precision camera in Chicago  works on the b1 If you need service contact them
847-430-8088.

He does quite a bit of work for Arca Swiss.
I don't remember his name but I think it was Bob?