First draft, ask if something seems wrong, it probably is:
Replacing the Hammond power transformer with the PT-2
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First, cut the wires from the old power transformer RIGHT AT THE TRANSFORMER - so they are as long as possible. Strip the ends of these wires 1/4 inch.
Now here is the worst part - remove the orange wire from the braid in which it is embedded, and unsolder it from amplifier terminal 4. You'll want to move the brown and purple wires away from that terminal so you can get at it without melting their insulation, and there are a lot of other things soldered to that terminal. Worse yet, you must eventually attach two new wires there - that's why you are removing the orange one, to make it a little more accessible. I'm sorry, I apologize, if I coule think of a better way I would suggest it - but I can't.
Then you can exchange the transformers.Be sure to mount the new transformer with the "missing tooth" (terminal 3) towards the back of the amplifier. Don't forget the core ground wire on the back right mounting bolt. The PT-2 terminals should be labelled 1-2-3-4-5 left to right along the back side, and 6-7-8-9-10 left to right along the front. Terminal 3 is missing.
Now you can solder the 2.5v winding, transformer terminals 6 and 7, to the yellow wires that go to the 2A3 socket.
Solder one end of the now loose orange wire to transformer terminal 9, the 6.3v winding center tap. Solder the other end to the transformer core ground lug on the mounting bolt, nearest transformer terminal 5. Now you can solder the green wires to transformer terminals 8 and 10, providing 6.3vAC to the driver tube.
Now the second worst part - adding two new UF4007 rectifier diodes. First, notice that there are already two diodes, from T1 to T5 and from T2 to T5. They have a white stripe at one end, and orientation is important. Both of them have the white stripe at the end that goes to T5. Now you must attach and solder the NON-STRIPED end of two NEW diodes to T4 - that messy terminal with the ground buss, the capacitor negative terminal, and the bleeder resistor. You can put them on the visible side of the terminal strip - cold comfort, but better than none. Take your time, be patient and careful. You have my permission to mutter foul oaths during the process. A strong light and good reading glasses may help. The ground buss wire was always a pain to solder on these amps, so be sure you have good connections.
Once the diodes are in place, solder the other ends to T1 and T2 respectively. This completes the 4-diode fullwave bridge rectifier. Now you can solder the brown and purple wires to transformer terminals 1 and 2, the 300vAC high voltage winding.
Finally, the black and white 120v power from the power cord is soldered to the 120v winding, transformer terminals 4 and 5.
The usual voltage and resistance checks should be the same as before, except for terminals 1 and 2.
If there are difficulties in this process, post on the Bottlehead forum and we'll deal with them, and revise these instructions if you find a better way.
