I'm in the habit of connecting a current-limited 9-Volt "bench" power supply to the radio when we find a blown TR40. First question for me is, "what blew it out?" The center leg of TR40 comes loose, the negative end of the second power supply to ground, and the positive side to the foil pad where TR40 center leg was soldered. The foil trace along the very front edge of the circuit board is also a suitable spot to clip the positive-side 9-Volt gator clip.
If the radio runs okay without tripping the power supply's current-protection, fixing the 9-Volt regulator should bring it back to life. And if there is still some sort of overload on that section of the radio's power supply, it must be cleared first. Don't want to blow out the new TR40 first time you turn it on. At the very least check with a meter
for a short to ground on the foil pad for TR40's center pin, after TR40 is removed. If you read a short, don't try to fix the regulator before the short is cleared.
That regulator circuit does a fine job when it works, which is most of the time. But I refuse to fix it when it breaks. We use a 7809T 3-terminal regulator chip, like the ones found in the 2950 radios. The pins don't line up correctly, but still far less trouble than the stock circuit.
My experience with repairing failed voltage regulators suggests that you'll need to replace both transistors and the zener diode at a minimum. If you miss one bad part and power it up that way, it probably still won't work. The labor to take the circuit loose just to check those parts is a lot more than just dropping in the 3-terminal regulator chip.
And if you don't have a handy 'bench' power supply to try the smokeless test first, this makes using the 3-terminal regulator chip even more attractive. At least it has a current limiter built into it. The factory regulator circuit doesn't.
Here's a pic showing this tick using a 8-Volt 7808T chip with a diode in line between its ground pin and the circuit board's ground foil. Serves to bring up the output voltage a bit. Only a ground wire is needed in place of that diode if you use the 9-Volt version.
73