The movement might look robust, oil sinks are very small and can not apply sufficient oil in jewels for 3120&3126 and so frequent servicing will be necessary to sustain watch functions and parts quality are also not that good according to my local repairer.
Hi there, If there is a problem with date change mechanism(not changing smoothly or jumps1.5 or 2 days) either manual hand advance, quick date function or by movement itself, it has got a problem with internal date driver wheel which happens quite often and stops the balance entirely due to the bloc