Thank you very much for the detailed answer, Chuck,
So tihs means that actually I can do the calibration in separate steps by running the CALxx procedure from the beginning to the end. This will fix then the FAIL04 problem once all the calibration constants are updated and the checksum is OK for all of them.
Sending the scope from Europe to the US and back is more than 500 USD (including the taxes, customs etc) so its beyond the economical repairs. The battery is good, it's just our lab technician pulled out all the chips in the failed attempt to quickly repair the scope by reseating the ICs and clearly lost all the settings once the memory has lost its power. Then the scope was thrown to the company auction and I scored it for 150$. After that I had to replace the U200 hybrid, opamps around, etc. Looks like someone decided to probe HV with this scope. After recapping the power supply I decided to calibrate it, but I didn't have by that time the time mark generator. So now, I'm better prepared and can go slowly running the CAL routines one by one.
I'm going to re-run tonight the CAL01. Could you, please, tell me whether I always have to join the zoomed time marks around the Y axis in the middle of the screen. Sometimes two zoomed traces disagree more in the middle of the screen, The service manual only precises that the traces must be joined around the division 6 (screen center) only for the step 1. I assume that in order to align the signal timing they have to be precisely aligned at x10 zoom around the screen center (vertical axis). So I'll try re-running the CAL01 with the signal alignment around the screen center.
Thank you again and all the Best,
Maxim
