SR-52 Feed Motor Noise

[NeXT]

I rebuilt the battery pack for my SR-52 programmable calculator and while the roller is getting soft, it will still pull cards through and it won't mark them up.
Problem is the geared motor in this thing screams like it has a dry gear or bearing inside and I can't see any way to get a drop of oil into it. Is it just non-serviceable?

 

[Leviset]

I was recently given an SR-52. It has its original battery pack (40+ years), still recharges and holds its charge!

 

[johnx993]

SR-52's and even the TI-59s are notoriously noisy compared to their HP counterparts.

 

[johnx993]

Also... the rubber wheel, even if it';s not gummy yet, can deform over time. This may add some resistance to pulling the card through smoothly.
Try disassembling the card reader, and try running the motor external to it's mount - does it still scream?
-J

 

[nolanx]

I think the SR-52 motor is sealed and not really serviceable. If it’s too noisy, replacing it with a similar DC motor might be a good solution.