kinser

Hey @Dominik_B -- there are two components there, the rectifier (2 legs) and the bipolar transistor (3 legs). I'll link to the ones I used below. And just in case someone is reading this years in the future and the reseller has removed their product pages, the rectifier is MUR1540G and the transistor is 2N6668 PBFREE. https://www.mouser.com/ProductDetail/onsemi/mur1540g/?qs=Gev%2bmEvV0iZq6LchZ03NqA%3D%3D&countrycode=US&currencycode=USD https://www.mouser.com/ProductDetail/Central-Semiconductor/2N6668-PBFREE?qs=l7cgNqFNU1ijRYXR1DLWNQ%3D%3D&countrycode=US&currencycode=USD

Oh don't worry, there is a rebuilt unit from an approved shop on the way for the actual aircraft. I just couldn't see a board that looks this straightforward and not try to resolve it. The pump itself is rated at 28v, which it gets when the high boost rocker switch is activated. This regulator is just used for low boost, hence the need for the lower voltage to achieve a lower output. Oh it's definitely a regulator. The transistors are on the backside. It kind of looks like what I would make for science projects in high school. And not just the board itself, but also the box containing it. It looks just like what radio shack used to sell as "project boxes". You hit the nail on the head with regard to the low vs high boost aspect. As for the transistors, they're mounted on the backside of the board and use the metal case itself for heat dissipation. That design does make things cumbersome though, because the transistor cannot ground to the case, despite mounting to it. So they couldn't use normal thermal paste for the backside of the transistor and instead has to use fiberglass based thermal pads and plastic screw insulation shims and mounts. It seems... sketchy. Ah, so no set voltage, just whatever is necessary to achieve to desired pressure. Thank you!

Recently had a boost pump regulator go out on me and just replaced the blown diode and transistor to get it back up and going. I'd like to sanity check the voltages coming out of the regulator though... what is considered normal from an output perspective? It is all adjustable via a trimmer potentiometer, just wondering where to start.

I've got a close friend (non-forum member) that is very interested. He has seen my M20S up close and personal a bunch, so he's got the Mooney bug. I'll shoot you a private message to get some contact info. We're based down in Charleston and can fly up to Rock Hill to take a look as early as this Friday.