Guru
Joined: 21/06/2018
Location: AustraliaPosts: 1172
| Posted: 11:53pm 09 Jun 2024 |
That is great news Dex, to be honest I woke up after a very sleepless night with a sense of dread, thinking what if it does not fix the issue, now what. You see after I posted, that I could account for maybe a 1.8% change not 7.2% I went to the workshop and started my inverter and tried to inject noise into both input pins of the opamps U1A & B and U2B. The only pin that I could make a small change with was U1B pin6.
But I even got a clip lead and coupled capacitors direct from the switching node before the chokes using 2.7pf all the way up in small increments to 100pf but I could not cause the amount of change you were experiencing. In hind sight my inverter was unloaded whilst I was doing all this so it wasn't exactly the same test I suppose - that was when I started doubting myself.
I don't want to boast but when you bought those boards for the inverter you also bought 40 odd years of experience and cunning with it, I consider analysing servo loops and noise injection and curing issues with them to be two of my specialties. I have fixed some amazing things in my career that other engineers gave up on, sometimes just shifting a wire to a different point on the same track solved problems. The secret is turning differential noise into common mode noise and the problems magically vanish, all the way up to RF.
The provision of the pads for the 10n cap insertion was my typical belts and braces approach is it possible this may be required ? - better to have it and not need it than the other way around.
Anyway thanks for working with me and happy invertering ! I have a confession I did the drawing in a hurry with my mouse using microsoft paint and the mouse freehand. It reminded me of trying to use an etch O sketch if you know what that is lol but I was otherwise engaged and had no time
Edited 2024-06-10 10:11 by wiseguy