In article , Uwe
writes:

I recently put together the old AC-1 tube transmitter for the 40 m band.

From a kit, or from your own collection of parts?

It oscillates nicely but does not have any power.
I know, it is not supposed to have much power but this one is weaker than
weak, the output couldn't drive any antenna.

How are you tuning it up and measuring the output power?

I was wondering if there are AC-1 owners/builders around here who could
suggest a few things to try, who are knowlegable about this thing.

First thing is the voltages and currents, as already suggested. Then there's
the size of the coil and your tuneup technique.

What sort of load do you have connected to the output?

73 de Jim, N2EY