The schematic is really cramped around the high voltage. It seems to be unregulated, which means a small change in the line voltage will change the deflection. Higher voltage = less deflection. That's why trying for high accuracy will be frustrating.
I concur with Demian--- HV is unregulated so calibration is susceptible to line voltage.
By how many percent is vertical calibration in error? If squarewave waveform fidelity isn't unduly compromised, perhaps you could use VR206 to get the needed gain? The only other remedy that occurs to me is adjusting a couple of fixed resistor values to raise available gain.
By how many percent is vertical calibration in error? If squarewave waveform fidelity isn't unduly compromised, perhaps you could use VR206 to get the needed gain? The only other remedy that occurs to me is adjusting a couple of fixed resistor values to raise available gain.
Bottom line is vertical calibration on this scope isn't critical. I have a new Digital for that. But I wanted this working and it is my anal retention character that will work to make it as perfect as possible when time permits. Resistor changes, higher gain transistors, maybe later. For now I am happy and grateful that you all helped me get it functional.
That reduces my task list to getting my Heathkit TT-1 working, and the hum out of my B&W speakers and Dynaco ST-70. Head is spinning about if and how to implement an isolation transformer. Every post and blog I read has a different and often disparate opinion. Can't yet afford a differential probe.
Thanks again,
Jeff
That reduces my task list to getting my Heathkit TT-1 working, and the hum out of my B&W speakers and Dynaco ST-70. Head is spinning about if and how to implement an isolation transformer. Every post and blog I read has a different and often disparate opinion. Can't yet afford a differential probe.
Thanks again,
Jeff