I have some issues with an Ameritron AL-811 for which I hope that members here might be able to give me some advice. I bought this amp from a friend at a good price, knowing in advance about these problems. The date on the sticker on the transformer is 7-94, so it’s about 25 years old. My problem has to do with the Load setting for the amp at lower frequencies. The amp seems to work well on 20, 15 and 10 meters, slightly lower output on 10 meters, but works as expected. However, at lower bands and in particular 160 and 80, the load control must be at the zero value (max capacitance) to get output, and although as the load control is rotated CCW toward zero (smaller dial numbers) the output power begins to peak, it does not reach peak before the load control reaches zero and stops, which leads me to think the amp is not properly loaded. It’s like it needs more C at the output of the pi network. I should add that on 30 meters the load control is also at zero, without the output power reaching a peak. I don't really consider using the amp on 30 meters due to the power limit on 30 meters being 200 watts, but I mention the loading issue on 30 in case that's helpful in diagnosing the problem. All of the testing listed above was done on a Cantenna as the load. The plate and grid meters always look “reasonable” but on the low side. It’s just that the output power can’t reach an output peak via the load control. I’ve read Tom W8JI’s comments at the bottom of https://www.w8ji.com/loading_amplifier.htm I’ve also tried temporarily adding extra C to the output as Tom had mentioned on his website (but I can’t find the reference although I’m sure it’s in there somewhere) by putting a coax TEE at the output of the amp, with one port of the TEE output going to a PL259 connected to some fixed capacitors. I’ve tried values of 330 pF, 660 pF and 1100pF bridged onto the output of the amp. No improvement of the load control at 160 or 80 meters. Can anyone offer some suggestions as to what I should try next?