Hi etothen. I have questions for you. There are pieces of information missing from what you've described that I need to help diagnose the problem.
First of all, are you sure you have an FX AMP regulator in that impact? If it's a HUMA regulator, then I can't help.
Assuming that it's an FX AMP regulator:
There are places where you mention what the plenum pressure was, but you do not mention what the tank pressure was.
For example, you said you increased the regulator pressure and the plenum pressure jumped up to 150 bar, but you didn't say what the tank pressure was at that time. If the tank pressure was also 150 bar at that time, then you may have actually set the regulator to some unknown amount above 150, but that's all the tank had in it at the time. If that was the case, then the regulator was doing exactly what it should do.
Another example is where you say the plenum pressure was 170 bar, but you didn't say what the tank pressure was at the time. If the tank pressure was, for example, at 200 bar, then that would indicate that the regulator is set to 170 bar and the regulator is doing what it's supposed to do.
Your observation that a high plenum pressure and a weak hammer setting is normal in that it would take several dry fires to finally drop the plenum pressure enough below the regulator set pressure to allow the piston to back away from the tiny hole in the end of the set screw and let air from the plenum to escape out to where the bottle connects to. This is normal behavior for an AMP regulator.
Your observation that when you removed the bottle tank, the plenum pressure didn't bleed out right away -- it required dry firing to drop the plenum pressure below the pressure that the regulator was set for. This is normal behavior for an FX AMP regulator.
Initially you said that you thought you were having a similar problem to that of the original poster, but this doesn't sound like the same symptoms. So far it sounds like your regulator is working as it should.
I did say that, IF the only problem with an FX AMP regulator was bad set screw O-rings, then you could bleed the air from the rifle and remove the set screw and replace just those two O-rings and re-install the set screw to fix the problem without needing to remove the entire regulator housing -- and that is STILL true. But I'm not saying there is anything wrong with your set screw O-rings -- so far, I just don't have proof that the O-rings are bad.
If you have more info that would help with a diagnosis, let us know. Cheers.
stovepipe
It is an AMP regulator as far as I can tell, hex head not screw driver, looks internally exactly as expected given the AoA FX AMP rebuild video.
The reg pressure was set at 107-109 'ish, then I turned the set screw an eight of a turn and the plenum reg pressure jumped to 150 which was the bottle pressure at the time. So I pulled the bottle off and dry fired to drop the plenum pressure to zero and reinstalled the bottle and the plenum pressure jumped back to the bottle pressure. So I did this a couple more times as a kind of control alt delete for regs and the behavior continued.
So next I put the bottle on and hooked it up to the pump (unrelated side note below on this btw) and the plenum pressure followed the bottle pressure up to 180 before I stopped the pump, removed the bottle and dry fired until the plenum was completely empty.
Then I tried screwing the reg probe in until I just felt it touch something, about two and a half turns and I attached the bottle again and the plenum reg pressure again showed the same value as the bottle. So it looked like the plenum reg was stuck open, but it did still hold pressure when I took the bottle off. I was surprised that it looked open, but only one way?
So I gave in, went to the AoA site video on the M2 reg rebuild and removed the reg, inspected the piston, surfaces and O rings and found that everything looked lie it should with the notable exception of a lack of grease. I lubed the reg parts up, but only with silicone oil and then and reassembled it as per the instructions with the one problem being that I tracked the washers but I did not see any difference in color in the last two counter to the instructions in the Reg breakdown video describing them as Black, they were the same color as the rest of the washers?
When I attached the bottle the plenum pressure still followed the bottle pressure. But now when I detached the bottle the plenum pressure dropped to zero so I hade at least changed that. So I ordered some thick silicone grease and a new set of O rings. I suspect that they were the original rings and that they had not been adjusted or lubricated with grease in a very long time and doing anything to them made them give up.
So I have experience building/rebuilding and maintaining scientific equipment including gas chromatographs (I am atheoretical/computational climate physicist that has had enough practical experience with machinery that I am quite handy on the experimental side) and in my experience the surfaces I inspected looked like they were in excellent condition, the washers looked and acted exactly as expected and I suspect that the O rings are the likely suspects so I will carefully pull it apart, grease it liberally, install new O rings (although I am not looking forward to that one inside the block even though I have the perfect flat spade shaped dental probe that I bent into just the right shape to get into that 'ringland' so here's to hoping) and see what happens.
If it works, great, if not, well it is only 11 dollars wasted on the new O rings and I will re-asses then. I would point out that finding AMP regulators to replace or rebuild it has proven problematic and if I cant figure out the sourcing problem I may end up wit a Huma regulator for that reason. If you know where to find AMP regs and or rebuild kits let me know.
I hope I properly, sequentially and adequately addressed your questions with my lengthy diatribe about my regulator problems and would love any information about what was happening and exactly where I blew it because there was an easyer fix I missed lol.
PS. It was probably replacing the pin O ring next to it's head wasn't it?
*I have just started this hobby again after a couple decades and am new to PCP's and have been shocked by the pressures these little instruments work at and further shocked that I could get a, so far, reliable pump for $150 that will regularly pump them up too 300+Bar.
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