hp-91 transistor substitution

[joseaem]

    Hi all.
I'm owner of an old HP-91 calculator (year '79 more less). It makes all functions so well, but it have a 'little' problem at display. All results and all digits have the minus sign activated or bright.
Open the chassis, I discover a transistor phisically break (see picture attached).
I need a valid commercial reference of this transistor, and perhaps the oher 2 additional transistors near, because for me it's impossible find them in tables and internet.

The numbers are 'M712 3-393', 'M712 3-374', '4-071 M741'

Thanks in advance