Yesterday I wrote that I was looking to replace the batteries in my newly acuired 37E. Thanks for those who responded.
At Radio Shack I purchased a cordless phone battery (23-967) with 2.4V and 1500mAh. They were the perfect size and had a soldered strap conecting the batteries in series. I let it charge overnight and tried it this morning. It worked for a few minutes but the the low voltage (litle red) light lit and soon thereafter the display went dead. The calculator works fine on the power cord.
Where did I make my mistake and what should I do now?
Thanks for your comments,
Dan