Re: TC Impact Twin mods

That's very helpful.

If I understand correctly then, at initial power-on, if the digital supply doesn't spin up, the MCU will never boot, and therefore the analogue supply will never activate. This would explain why neither switching supply is spinning up.

I therefore first need to understand why the digital supply isn't spinning up. Looking at the schematic, it appears that the switched 3.3V output rail is what provides the shunt regulator feedback for the digital supply switcher. I'll first check the output filter caps C518,...

Re: TC Impact Twin mods

Hi Khron,

Thanks so much for the reply.

Yes, at least it would appear so. The brick's output label states 12V DC at 2 amps. With the brick plugged in, I'm measuring on the internal side - 11.73 DC at TP 881 (junction of L62 & C524), TP930 (Pin 2 of TR3 14220094-3 transformer), TP 896 (junction of L61 & C307), and TP915 (Pin 2 of TR4 14170143-1 transformer).

Looking at the schematic of these switchers, and if I understand correctly, the only thing the unit's power button does is select whether the unit...

Re: TC Impact Twin mods

Hi Everyone,

I have an Impact Twin that recently died. It won't power up or turn on. The only light I get is the internal red status led near the fire wire interface when it's plugged in with the unit turned off. I am suspecting that one of its internal switcher supplies has crapped out.

After doing a bunch of Googling around, I managed to get my hands on the schematic for the unit's dual internal switching supplies, which I've uploaded here.

I've read in numerous places that the filter caps near the internal voltage...

Re: New Members - please post your introductions here

Hi all,

My name is JC. I'm a digital signal processing (DSP) engineer specializing in pro audio and visual special effects. I'm also a professional concert sound engineer, and also do location and post-production sound recording and re-mixing for film. When not on the road or in the studio, I'm based in New York City. I like dogs. I like cats, but I don't like spiders or snakes. I love to reverse engineer hardware and write software. When things break, I fix it. I especially love old vintage, tube-based gear. I'm...