HP-33c

[burkhard]

(05-04-2019 02:40 PM)Wyatt_Irk Wrote:  This calculator came with the battery spring tabs removed, but an AA nimh rechargeable with a flat (-) terminal fits. Is it safe to use the charger with this set of rechargeable batteries in place?

It isn’t risk-free to use that calculator’s charger with the *intended* batteries.
If the modified calculator loses contact with the batteries while plugged in and turned on, it will smoke the ACT.

If you want to do this instead of charging off-board, I would at least be sure it is kept tuned off while the charger is plugged in.