Something not quite right.

Factory QC was not always that great, especially on Mondays and Fridays. (Like cars). Hangovers, domestic fights, and wanting to get the heck out of work for the weekend are common for poor workmanship.

I ran into one RCA console where no matter what I tried, I had one dead sw band. Finally had another tech look at it. Not my mistake, but he found that the FACTORY assembler had mis- connected a wire on the wafer on the band switch. It never worked from day 1 !!! 
I should have caught that one, but couldn't see the forest for the trees, looking for my own non-existent screwup.

Radio worked perfectly after he moved the wire to where it was supposed to be. So no factory QC on that set. They typically just grab one off the assy. line every so often and test it. 

Please keep us up on your tests and findings. This is an interesting case.

Image of the underside of the 12SQ7.
You can see where pins 5,8,3,1 are connected. 
I'm going to cut the wire from pin5 at pin8 and swing it over to pin4 for starters.

Frank B 
Yeah... I thought it looked a bit off but I thought it was me not reading thee schematic correctly. Seeing as the solder connections look factory made, I thought maybe they upgraded it for what ever reason. If that change they made it not work, How did it leave the factory in that condition?
I am going to change it per schematic to see what happens. If still there is no sound after that, I missed something somewhere.
Thanks

Pins 4 & 5 are the 2 diode plates in the 12SQ7. They are the detector and it's common practice to connect both in parallel.

Possibly they are connecting pin 5 to pin 8- the heater, but that makes no sense to me, as that could put hum from the filament into the radio if the plug was reversed.
The sch you drew shows one diode plate grounded. Has somebody rewired the radio- or just possibly if it was of WW2 era, they modded the radio because a SQ7 was not available.

I made a post a long time ago about tubes being subbed during the war, as no spares were available. Wiring changes were made to use other tubes.

I would rewire the radio per the schematic, if it was mine.

That is a hot chassis set and appears to have 2 different grounds. Don't be fooled by measuring to the wrong ground and use an isolation transformer when working on it. I blew breakers in the tech school working on a hot chassis set many decades ago, by not using an isolation tx.

The first thing I'd do is to touch the hot end of the volume control with your finger or an operating soldering iron and see if you get a large growl from the speaker.  A good audio section makes the same growl when you tickle its grid as a lion does when you twist his tail...

If no joy, then take some voltage measurements in the audio section.  The plate and screen of the output tube, the cathode of the rectifier.  Have you checked the power supply?  Have you recapped it or done other work?  Start at the speaker, then work back towards the antenna.

If this forum is like mine, the forum software won't let you download PDF files directly to the forum.  You have to have a downloads section or other such extensions that will allow posting PDF files.  There are conversion apps you can use as well, but those are above my pay grade.

Here's an odd one or maybe I'm missing something.
Once again I cannot upload the schematic file for this radio. I've been successful before but not this time. I had to take a pic.
I'm looking at the schematic against under the chassis. It could be me but the 12SQ6 wiring doesn't match up.
My crude drawing shows pin5 plate connects to pin8. On the schematic pin5 and 4 go to the IF can.
What am I missing something?
Tubes light up but no sound... not even a hum. 
Looks like the solder joins were factory made. I don't think anyone messed with it.
This is another one I put aside as a head scratcher a couple years back but never noticed the difference until now.
Thanks for any help anyone has to offer.