I just acquired a 7B53A in good condition with option3 that has a good delayed sweep but no mains sweep. I do not have another working low sn 7B53A with trigger board pn670-1865-02. Cleaning the switch does not help. I have had very little success in the past troubleshooting ECL chips. I would love to get some good advice and would like to? buy or swap for a known good 670-1865-0? pcb. Please respond off list and I will try to do same. I have a good 7834 scope ready to sale or trade. I want a good 7CT1N.
