Just an update.... finished upgrading my L75.
Used the L75 for the first time the last night.
As reported by an old Heathkit HM-102 meter, I was able to obtain 500 watts output with 50 watts input on CW on 40 meters to a Heathkit Cantenna Dummy Load.?
Compared that read out against a Collins 312B-5 console and there it shows 600 watts. But the Relative Output function of the L75 shows way less.
Tried to adjust the Relative Output with the pot on the back of the L75, reaching the end of adjustment, but was only able to reach 300 watts. So something is still wrong there.
?
Apart from that, was able to use the amp to make a few contacts on SSB, CW without problems.
I kept an eye on the meter and adjusted accordingly to the manual (dip the plate and loading) thus not exceeding the plate nor grid mA stated there.
?
Also made a lot of contacts on 40 and 20 meters FT8 not exceeding 200 mA on the plate of the L75 (20 watts on the exciter) and performed very well. Got new countries into my log. I know this amp is not designed for digital 80% duty cycle modes but can be used with great care with very low input limiting thus the output.
?
Tested other bands and did well too. Only bands that I heard small arching was on 160 and 80 against a dummy load. Don't have an antenna for those two bands any way. From 40 and up was OK no arching.
?
So that concludes my report. Have to check on the Relative Output circuitry to find out why is not reading well.
i did adjust the meter for Plate and Grid according to the manual with a 1.5 VDC battery...
73 Rob
YS1RS
Roberto - YS1RS