97S low battery Indicator with no display

[John Garza (3665)]

Interesting problem. I did a printer refurb on a 97S that was otherwise working well - except the paper advance problem. When I assembled everything only the low battery indicator was lit, no friendly 0.00 in the display. I tried multiple battery packs (all good), and even tried the charger for a couple of secs. Still no good. I did double check my connections/disconnections with the post pins during the work, and then triple checked after the problem arose. No issues there. I worked on an anti-static mat and bench humidity was 61%. With the cover off, I noticed a transistor was overheating on the main logic board. Markings are a Motorola 931 4-668. I take it as an internal HP part number. That looks to be Q2 according to the 97 service manual. However the component layout diagram in the manual does not match my machine. Just wondering what could have taken out the transistor, and if there is anything else that might be wrong with the unit causing the transistor to fail. Anyone have experience with this sort of thing in Topcats? -J

The internal arrangement.



The transistor in question: