Reply To: OSSC 1.6 Not Turning on?

NewHome Forums OSSC & OSSC Pro OSSC – Discussion and support OSSC 1.6 Not Turning on? Reply To: OSSC 1.6 Not Turning on?

#22920
Morpheus_79
Participant

D5 is TVS diode that clamps voltage to 5V (in reality effective clamping voltage is a bit higher and depends on current), protecting from surges and overvoltage. When continuous overvoltage (or negative voltage with more than ~0.6V amplitude) is applied, it burns into a short circuit so that downstream devices are still protected. That eventually triggers overcurrent protection (e.g. fuse) if such is present. The diode and fuse are placed before power switch, so if you hadn’t power turned on yet, then you almost certainly did not damage anything but the diode.

Thanks for clarifying it marqs. I was looking for the OSSC 1.6 schematics but couldn’t find them. So i took an assumption from the back of my (bad) memory.

I only just remembered, that there were OSSC 1.5 schematics available and i saw, that F1 and D5 were indeed placed before the power switch:

I’m just going to order F1, D5, U5, and U6 to be on the safe side, but I’ll certainly start with replacing D5 first. Not sure why this particular diode is so hard to find in stock anywhere. Anyone know a secret about finding them somewhere that won’t take months? Is an SD05TCT from mouser okay as a substitute? The specs look the same except for the voltage breakdown, 6V instead of 6.2V

I’ve used a SD05T1G for D3, D4 and D5 in the past. But at first glance an SD05TCT seems to be suitable too…