09-10-2019, 02:24 PM
OK - so that's roughly what I guessed. Thanks...
My curiosity remains piqued, so I'm pretty keen to get to the bottom of how this works, but there's every chance I'll have to give it back before that happens.
One of the frustrating problems is the SMT transistors don't have markings that lead to positive identifications. Some aren't recognised at all. There's been a fair bit of having to figure it out based on the surrounding circuitry, which isn't ideal. Just look at how much circuitry is driving the main switching transistors - it's looking like it's a discrete control scheme. Having had another look over lunch, I'm increasingly sure the TL594 is just controlling the fan. Kudos to whoever did the PCB design - they did a good job of fitting it all onto a single-sided layout, but it's not easy to reverse-engineer.
My curiosity remains piqued, so I'm pretty keen to get to the bottom of how this works, but there's every chance I'll have to give it back before that happens.
One of the frustrating problems is the SMT transistors don't have markings that lead to positive identifications. Some aren't recognised at all. There's been a fair bit of having to figure it out based on the surrounding circuitry, which isn't ideal. Just look at how much circuitry is driving the main switching transistors - it's looking like it's a discrete control scheme. Having had another look over lunch, I'm increasingly sure the TL594 is just controlling the fan. Kudos to whoever did the PCB design - they did a good job of fitting it all onto a single-sided layout, but it's not easy to reverse-engineer.
