Over the last few days, I have done a lot of chainsaw work made considerably more difficult by my inability to properly tension the chain. After opening up the saw I discovered the root cause of the problem. The threaded shaft used to set tension was fractured (see the top right of the photo; I removed the broken section of the shaft from the adjustment block for clarity). Studying the design for a few minutes led me to conclude that it is fundamentally flawed and destined to fail again even with a brand-new shaft. Still, I needed to get the saw working again and searched for a replacement part on the internet only to discover that the part I need is now obsolete. Fortunately, I also discovered that the entire mechanism had been redesigned and was available as an upgrade kit for just over ten bucks. My anger at the shit design was replaced with appreciation for the improved version. Even so, the new version is simply a beefier variation of the original design and does not address the fundamental design issue (the adjustment block puts a flexing force on the threaded section which will fatigue and fail over time). Only time will tell how much longer the new version will last.