The 50v disable board going into the brick, the controller board has a line directly to this to shut down for whatever reason, right now just high SWR, but the mica insulator behind it, or the shoulder washer didn’t like to stay insulated from ground. I suspect moving things around too much and the stiff wire going to the brick. after replacing this I put a fuse inline. It didn’t help those FETs today 🙁 and there was no error to disable. I need to make a high speed pulse detector to stop the power if it encounters an EMP lol
Well, the brick cooked 2 more FETs today, who knows. Power supply interference maybe I don’t know . also an input filter cap popped along the way, due to? cause of? who knows but i am looking at a better RF choke on the power supply line coming right into the amp. This pic shows whats there and what popped, it cooked a cap into pieces and there is only supposed to be 50vdc on it and no RF. well, I think maybe there is a ton of RF on it over 14mhz..so tomorrow I’ll try that direction. FETs replaced and re-biased. its working again but i’m not running it over ~50 out until I figure out how the smoke is getting out of these……FETs!!! I cleaned the board up, installed some 3.1kv .01 and a 6kv .001 cap in there. if that pops there is some serious shit going on in there!!!
snap! Crackle POPferrite beads around the power lines coming in..maybe not helping?
found out the caps they had in the kit were under rated. ah HA! a gotchya….
Here is the schematic I went by for the amp itself. the Designers are listed on the bottom.
I spent a lot of time today on this beast again. Cleaning up this cabling mess. There is RF getting in everywhere over 14 mhz (20m Band in Ham-lingo) so I put the controller and the Micro , which is an Arduino Mega, in a shielded box..more on that later too. I’ll finish posting the 80 pictures I have taken and some other documents as time permits. Yea, no job I got time 🙂
As Shemp once said, “No wonder the water isn’t running , these pipes are full of wires!!!” well, we certainly have a few here.
What your looking at here was the first thing we worked on, Peter KA1QEK found some copper and aluminum heat sink. He had a machinist friend work it out so they were connected pretty flat. Lots of hardware on top and underneath to hold it together, our concern was dissipating 1kw off this thing. The fan would be moving air thru the bottom, I’ll post a picture later to show you the openings underneath it. I was still undecided at this point how I would mount it in my case i had gotten many years ago just for this project! I knew someday it would come in handy! Yea I tend to hold onto things! the FETS are the 250w SD2933’s, we got them as pulls. You do need to test them first as some can get damaged, but all mine were fine.
this works but instead of your finger, for these you will need to put the positive lead on it as you’ll need a higher voltage.
Believe me, this has been going on a year we will get into it later on how I know this , I cooked the first set last week (~52 weeks into this haha)