I'm planning on building a new layout, which I want to power passively with an old first generation TIU I bought for a reasonable price, because of two dead channels. First thing I did was upgraded it to 6.1 then tested each channel. Fixed 1 was popping the brick's breaker, caused by an open TVS, which I replaced and is now working fine. Fixed 2 and Variable 2 tested good, but Variable 1 was stone dead in both fixed and variable mode. I tried a factory reset, still dead. I checked the TVS, good, no continuity. So I assumed a bad FET. After removing all four, I diode tested them and to my surprise, they were all good. So I replaced them anyway and still have a dead channel. No other components or traces look to be burnt. Is it possible something happened to that channel during the upgrade? This TIU still had it's original program so when I upgraded it, I did it in two steps, 5.0 then 6.1 and did a factory reset after each. Has anyone ever experienced losing a channel after an upgrade?
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