HP 97S I/O transistors replacement

[Paul Berger (Canada)]

(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.

The service guide lists the HP house numbers for the transistors and there are cross references to "standard" parts are available, the problem is that not all parts are listed and could possibly be custom parts. There are no know specs listed for the HP parts all you can do is guess, that is what I have had to do with some HP equipment. If you do have a working 97 you could check the transistors for gain and from the circuit diagram you can figure out polarity. You will notice that the layout of the main board does not match what is in the service guide, however the circuitry is the same.

I would agree with the previous post, I would not be optimistic of anything surviving being connected to 220VAC, even if it was only for a second.

Paul.