HP 97S I/O transistors replacement

[armania72]

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.

[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.

[armania72]

The calculator was bought at the flea market, and I did not know its voltage, the wire was going out of the battery compartment, it was necessary to check the efficiency, now I understand my mistake, but there is a desire to restore, for starters I need the parameters of these transistors. If anyone knows, please write.

[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.

[Dave Frederickson]

From the second pic, the "M152" part is marked 4-713 which is an 1854-0713 (HP shorthand). This would be Q4 on the Logic PCA in the 97 Service Manual.

Perhaps with the service manual you can correctly identify the other parts. It looks like they could be Q1 and Q3 on a standard 97 Logic PCA.

Also, I agree with the others, it's probably fried.