I have a TS-830S that was initially doing about 60W in CW at 10m and 70W at 40m. I've heard these things are capable of at least 100W.
Determined, I started doing research on what components to look at in addition to the tubes. I'm able to get ALC with CAR at 5 on 40 and 8 on 10 meters- so I think the drive is sufficient. This lead me to suspect the final tubes.
Before getting a pricey set of tubes- I tried some of the cheaper avenues. I have replace the C7 C8 and L1 components of the final cage with a kit from hybridrestore.com. Next- I replaced the cathode and screen resistors with another kit from the same vendor.
I didn't get much power out of that- but I did notice the tubes we easier to neutralize. I use an SDR running SDR# as my second receive and tune to a dip in signal strength with SG.SW OFF. The dip was much sharper and more pronounced- but it could have been placebo.
Finally I decided to try new tubes. I got a pair of NOS tubes from an ebay vendor with lots of good rep. I put them in the radio and "cooked" the getters a bit- maybe 5 minutes- with the SG switch off. Clearly that wasn't long enough, because a tube arched and the resistors went out of spec.
I found some 1/2W metal film resistors on ebay in 100ohm and 20ohm for replacement. And this time cooked the getters for a good hour.
Things appear to be working. And I'm getting about 90W on 40m and 80W on 20m. But I want to get more out of it.
I understand that the power differences here are negligible. This is more for my satisfaction of getting and old rig running at peak performance again.
My question is- what would you suspect next? Maybe the tubes are not quite "NOS" as claimed? Should I try newly manufactured Chinese tubes that haven't been sitting on the shelf for 30 years? Should I replace the HV caps? I'm getting an 800V reading on the HV meter. Anything else to look at next?