Or download TDSL Personal Edition.
http://www.duncanamps.com/tdslpe/ It'll give you all the info you need including pinout's with the nomenclature. You can look up almost any tube made.
a 6an8 is a triode/pentode (two tubes in 1). Each side has a different function. pins 1 thru 3 are the triode, 6 thru 9 are the pentode and 4-5 are the heater.
On the 6AN8 pinout is as follows:
Legend: a=anode (plate), g=grid, k=kathode european or Cathode for US, h=heater or filament, g2= 2nd grid (or screen)
1 = a''
2 = g''
3 = k''
4 = h
5 = h
6 = a
7 = g2
8 = g
9 = k+g3
taken from TDSL
All the HEATERS / FILAMENTS on the pioneer are AC Voltage. Either you measured them in DC or you have no voltage to them. Check them again in AC.
Learn how to read the pin #'s on the sockets. Generally #1 is to the left of the space or locating pin(on an octal) and they go around clockwise to 7, 8, or 9 depending on the type of tube(couterclockwise on the top of the socket). Look at the sockets really close. There are usually numbers right next to the pin on the bottom.
Swap V5 and V6. Check all the voltages again. If the Bum voltages follow the tube, get a pair of new 6AN8's. If it doesn't then you've got problems in the circuit.
The pots you are replacing are Tube BALANCE POTS. They balance the tube load in the pair. On a push pull output you want the tubes to be as close as possible when making power. One tube that isn't pulling it's weight throws all the load on the other tube. The pots will even this out. These are not BIAS pots and there are no bias pots on the 801. Which is why I put that blurb in there about the bias pot replacement.
Take a picture of these "HUM BALANCE" pots, and trace them out exactly to which pin on which tubes. I believe you're getting VR8 and VR9 (hum balance) confused with the output balance control. VR8 and VR9 are 2 pots in the Heater circuits that are best left alone unless there is a hum with the volume down, and then they get adjusted for minimum or no hum in the heater as they are AC.
ARE YOU READING THE SCHEMATICS? Doesn't seem to me that you are at times. If you are I apologize, but some of the questions and statements you are making lead me to believe either you aren't or you are getting confused by it, and don't understand it. If you are having problems let us know.
SLOW DOWN! Everyone gets the 1st time jitters, but in the end 99% of the time all it does is cause more problems due to mistakes, and getting ahead of the help. The closer you get to the end the more you want to rush. This is the time to SLOW DOWN, Step back, take a few deep breaths, take a walk to clear your head. Slow, methodical work will get you a fully working unit faster than trying to rush it....(think the turtle and the rabbit. Who won the race?) Quite a few of us are "retired" but all that means is SWMBO is now the boss and she don't pay too good. Plus you're never done. So hold on, we'll get to you within 24 hours or so.
Swap the 6an8's and recheck the voltages. If they move, replace the tubes to get a matched set. If not start checking resistors (lift one leg), and check all the electrolytic cap polarities in the area. Also check grounds.
BTW Pin 8 on the 6an8 is the input lead. You won't get a votlage on it unless a signal is going thru it. Ohm out from pin 8 to the center tap of the BALANCE CONTROL, and you see close to zero.zero ohms.