can you run the HP 55 on AC adaptor without batteries?

[dmh]

(02-28-2021 11:31 PM)Steve Simpkin Wrote:  

(02-28-2021 10:41 PM)dmh Wrote:  I know this should never be done for the Woodstock and Spice series and for the 67 but what about the 55? Is there any risk of causing damage?

Can someone advise definitively regarding the 55 with the technical details to confirm if so and why?

TIA, dmh

Yes. Running the Classics on AC power without a battery pack is safe. The AC power supply on these models has a separate regulated power source for the calculator logic.
There was some concern about doing this on the HP-67 (which is not really a "Classic") but it appears safe on those as well. More information here.

https://www.hpmuseum.org/forum/thread-82...l#pid72353

Regarding the 55, thanks!

Regarding the 67, I read that thread you shared (thank you) and am still confused about the 67. Towards the end it seems to go back to saying don't run the 67 without a battery.