HP 97S I/O transistors replacement

[Kees Bouw]

(10-19-2017 11:07 AM)armania72 Wrote:  Hello everyone! A week ago I got the HP 97S I / O calculator. From the calculator there was a wire without a plug, from the case where the battery compartment, it was connected to the mains 220v for 1 second, the screen caught fire, then the wire was pulled from the power socket. Now we are repairing with my master. There transistors were out of order: M152; M141; M211. I need their technical data to replace. I have a service manual, but I have not found the technical parameters of transistors. I very much ask you to help, since I do not have such opportunities as you. Thank.

Hi,

If you had only checked the HP museum website before you connected the HP-97S to 220V you would have known that not any wire coming out of this machine should ever be connected to such a high voltage. The calculator operates on 5V DC. If you have no battery and no charger, then you could have connected the battery contacts to a 5V DC power supply (observing the correct + and - of course). As it is now, I would not be surprised if the calculator is beyond repair. Replacing a few blown up transistors will not fix it I am afraid.

Kees.