[morzh]

Last I used it was when I restored my 118 this summer. Was fine.
Today I received a 6T5 tube and decided to check it. As usual first tried the line.....it was at half the value where it usually is normal. It took me to move the potentiometer all the way up to bring it 2 divisions short of the middle. Without the tube inserted. 
Checked the line voltage, it is fine, 118V.

Tied to run the potentiometer back and forth, and power switch on/off a few times, no changes.

Will have to open it up.

[morzh]

Today opened it up. Pretty clean and all.
Turned it on to confirm the problem was still present, it was.
I thought, since the change happened suddenly, it had to be a contact, so I pulled and re-inserted tbe 83 and 5Y3 tubes. The problem had disappeared after that.
I washed the panels' contacts with alcohol (easy on the 83, not so on 5Y3 but I gave it the best effort) and then applied some Deoxit with cotton swab. In 5Y3 I first scraped the contacts with some sand paper since I could not wash them well).

After it tested the 16's tubes.
Works fine.

[doug-5er]

Today opened it up.  Pretty clean and all.
Turned it on to confirm the problem was still present, it was.
I thought, since the change happened suddenly, it had to be a contact, so I pulled and re-inserted tbe 83 and 5Y3 tubes. The problem had disappeared after that.
I washed the panels' contacts with alcohol (easy on the 83, not so on 5Y3 but I gave it the best effort) and then applied some Deoxit with cotton swab. In 5Y3 I first scraped the contacts with some sand paper since I could not wash them well).

After it tested the 16's tubes.
Works fine.

Sometimes it's just the little things that drive you Glad you got it working