We don't really care that you downloaded the manuals and put them on a CD for your personal use.
The PAS-4 preamp was created by Panor, a Japanese company who bought the rights to the Dynaco name and produced the PAS-4 in a plant in Taiwan. Some made it over here but they never sold in large volumes in the USA like the PAS-2 and PAS-3. Very rarely does one show up on Ebay or Audiogon and when they do they go for $500-$600. The PAS-4 is a much better sounding preamp than the PAS-2 or PAS-3.
As for starting up your old ST-70 the best thing to do is use a Variac to bring the voltage up slowly over a period of an hour so the quad cap has a chance to reform gradually. Most Dynaco users, however, don't have a Variac so here is what I would do in this order ..
1. Pull the rectifier tube and start the amp up without a rectifier. Let the amp stay on for 5 minutes or so and check that all the other tubes light up OK. If the amp was working OK when you put it away there should be no problem here. This just tells us that the power transformer is working OK. Turn the amp OFF.
2. Open the amp up, set your meter for its highest resistance scale. Place the black probe on the chassis and the red probe on each of the 4 sections of the quad cap and measure the resistance on all four sections of the quad cap. What SHOULD happen is that you should get a RISING RESISTANCE. The resistance will gradually go up as each section of the quad cap charges from the battery on your multimeter. If the resistance on each section is over 1 MEGohm (1,000,000 ohms) you are probably OK. If the resistance peaks out at 5000 to 10,000 ohms the cap is probably bad and should be replaced.
3. Assuming the resistance on all four sections of the quad cap is sufficiently high then plug in the rectifier and turn the amp on and KEEP YOUR EYES ON THE RECTIFIER TUBE AND YOUR FINGER ON THE POWER SWITCH. The key time is about 10 to 15 seconds after you turn the amp on. The indirectly heated 5AR4/GZ34 rectifier will have heated up sufficiently to start applying high voltage from pin 8 across to the quad cap. If the quad cap is weak or has gone bad it will not accept the high voltage and the rectifier will "arc over" and you will see sparks inside the rectifier. The second you see anything abnormal inside the rectifier > you shut the amp off! (you still have your finger on the switch - right ?)
The quad cap is the weakest link on an old ST-70. Replace it with the CE Distribution or the Dynakitparts 80, 40, 30, 20 quad cap, Both are very well made and should last along time. This cap should be oriented properly > All you do is place the 80 section towards the back of the amp and all the other sections will be in the proper place. If you have a Mark III instead of a ST-70 use the one from Dynakitparts because it has a slightly higher voltage rating.
Let us know how you made out this weekend when you "fire her up" ?