I have a 3B-ST that I purchased new - not sure of the year, but more than 20 years ago.
I shorted the outputs about 10 years ago and Bryston kindly sent me replacement output transitors which got me going again. The unit has been sitting in a box for the last 8 years or so, and I honestly can't remember if it was working when I packed it away. Anyway, I thought I'd start using it again, plugged it in and it was dead. Had a peek inside and found the top the LM317 regulator floating around in the case. Further inspection shows that it had, indeed blown it's top. Also, I found a defective zener (z5/1N4741) and cap (2U2 tantalum/C23) which makes sense - this would short the output of the LM317.
Luckily I have a bunch of LM317 and will order some caps and zeners. However, a post that I found on DIYAudio had the exact same problem. When the poster emailed Bryston, they said they were no longer using tantalum caps, but he doesn't say what was recommended as a replacement.
The power power supply board is marked 3BST-PSB 4.8 JUL 96, with a hand written date of 4/28/97. It's 230 V.
I have attached a schematic (V5.0) from the Bryston website, and I've marked the defective components. However, I can't see the MJE172 tranny (T4 and T10), on my board plus a few other things are different.
Wondering if anybody can help with the tantalum replacement and a better schematic.