As part of my retrofit project on my Boss 8 Series II mill, I went searching for a decent factory manual. I was able to download some bits and pieces but never a complete and clear copy. I found a brand new Bridgeport R2E4 Manual on ebay for $20 including shipping. This appears to be a factory original with all the wiring diagrams, including the logic board details. The official title on the manual is Bridgeport Series II CNC R2E4 Maintenance Manual (Code # 11040827) This is a 8.5" x 11" bound manual

The seller claims to have more available: jgreen32@msn.com