Looking for (idler?) gear wheel of HP-46 printer unit

[Sadsilence]

Sorry for not explaining detailed enough. It has nothing to do with oscilloscope quality at all. It is a problem of physical access. To check signals, printer unit has to be powered and connected to a sending device. When HP-46 is only available sending device you must run calculator and printer unit at least partially disassembled, a 110/220VAC transformer is smiling at you, connection line between printer and rest of calculator is short and so it is difficult to connect/hold your oscope probes to right positions in that mess of "floating" calculator parts. Generating right test patterns by initiating coincident print commands might be tricky, too. I feel calibration was done useing a special test device back in 1970s. Of course it may be much easier than I thought and I simply missed right entry point. Any additional information is highly appreciated.