[sam]

  getting ready for  37-116 not looking forward to it
kirk said it worked     but I brought up on veriac   blows my circuit at 90v
so I`ll first check trans. and replace caps
but have question on part  128 potentiometer   see nothing about it ?   whats it do / for ?
top right switch looking thing

[morzh]

That will teach you to trust Kirk. 

Now, even if it were working, the tubular cap from 50-s would make me suspicious.

Sam, as a member here you are as old as dinosaur's crap by local standards, you should know better than to power un-recapped chassis.

37-116 is a beast.

Start with all the caps. There are quite a few backelite blocks. Plus those caps in the RF chassis, not exactly the best accessible ones. Plus the electrolytics,, one of which is on the photo.

If you need help, let me know, I've been through one.

[Ron Ramirez]

> but have question on part 128 potentiometer see nothing about it ? whats it do / for ?

It's to adjust hum...or, more accurately, to null out hum in the 6B4G output tubes.

[Chris h]

You might want to take a look at that choke, shown in your photo, too. I had two 37-116 chassis and that choke was open in both of mine.

[morzh]

Sam

To elaborate on what Ron said, some tubes, especially directly heated like the 6B4G (my version BTW has 6A5, indirectly heated - 37-116 came in both ways) will produce some hum due to the filaments being fed 60Hz (oops...sorry...cycles) AC.
Introducing a low Ohms trimpot with he wiper to the GND allows to minimize the hum.
It is likely that the trimpot was not touched so it might still be in the position to null out the hum.