HP 97 calculator printer issues

[isanchez]

Dear all,


I am repairing an HP97 printer. I have replaced the paper tracking rolls. I also have replaced the gearwheel, for a metallic one.

The printer prints with high quality and the interspacing is perfect..nearly 10 over 10 of quality.

The thing is that the noise has been increased a little bit. It is more noisy now. I have oiled and reviewed all the parts. I do not know what cause this noise. Maybe the metallic gear? apparently no.
The noise is present when the header goes back to the stand by position, in the more left side. When moves left for printing seems ok, but it is when reurns back whe i find this noise appears.

can you give me any idea how to proceed? is is not really annoying, but I would like to reduce it, if possible.

On the other hand, I have seen that a couple os resistors(?) have been connected to the board. I do not know what is the purpose...I enclose a picture

thanks and kind regards

Ignacio