Hi, I'm trying to repair a friend's cheap USB capable turntable. It's powered by a 14V wall wart and has a lot of SMD electronics inside it.
I found an apparent Schottky diode (SMD component with a cathode band marked as SS34, according to Vishay has a 40V max DC blocking voltage) with some odd behavior- I can measure single digit resistance across it in either direction using an ohmmeter. When the unit is receiving power from the wall wart I can't measure a potential difference across the diode, though I can measure about 14V from another, nearby diode. I tried shorting across the suspect diode with a normal 1N4004 diode but that didn't help (not surprising given it's acting like a wire on it's own).
My questions are 1) this is bad behavior for a Schottky diode, right? and 2) is there any reasonable circuit design that would have single-digit resistance in both directions in parallel with a Schottky diode? I have no schematic and wasn't able to find one online.
Trying to decide whether it's worth it to try and replace the Schottky or not. Thanks for reading!
I found an apparent Schottky diode (SMD component with a cathode band marked as SS34, according to Vishay has a 40V max DC blocking voltage) with some odd behavior- I can measure single digit resistance across it in either direction using an ohmmeter. When the unit is receiving power from the wall wart I can't measure a potential difference across the diode, though I can measure about 14V from another, nearby diode. I tried shorting across the suspect diode with a normal 1N4004 diode but that didn't help (not surprising given it's acting like a wire on it's own).
My questions are 1) this is bad behavior for a Schottky diode, right? and 2) is there any reasonable circuit design that would have single-digit resistance in both directions in parallel with a Schottky diode? I have no schematic and wasn't able to find one online.
Trying to decide whether it's worth it to try and replace the Schottky or not. Thanks for reading!
