I have the EICO Model 635 Tube Tester and the Operating Instructions and Tube Data Information. This book contains the; General Description Warranty General Information Tube Testing Procedure Testing Picture Tubes All Vacuum Tube Switch Settings Parts List Schematic Diagram Would be willing to make a copy and send. Requester to pay for repo costs and shipping. I am having trouble with socket "A" in mine. It's a 10-pin socket, looks like a standard 9-pin with a 10th in the center of the socket. Would appreciate info on where I can get another socket. Cheers, Bob McKee rlmdlm01(a)juno.com