Hello everyone. I’m replacing the selenium rectifiers in my old Mac MR67 and there’s some debate about how to do this. Amongst all the posts and threads I’ve read, a number of people have said the Schottkey sic diodes are the way to go, but they are in the minority; nevertheless, I chose a pair and in doing so, I went by spec, choosing the one with near highest performance. What I didn’t realize was that the heat sink is tied to the cathode and if it touches anything will result in an immediate short. There are sic diodes with isolated bodies, but not the pair I purchased. How good or bad of an idea is it to cover them in heat shrink as a way of insulating/isolating them?
Please let me know and thanks,
John
Please let me know and thanks,
John
Being they dont belong in linear supplies the easy solution is using a rated common isolated silicon rectifier for slower and continues current levels found in linear supplies.
Common sense would be the rectifier average temp under operation and the thermal threshold of heat shrink.
Regardless it will be under high temp for its lifetime and likely degas and dry out quickly. Doesnt seem ideal
Since i wouldn't want to smell it or worry about fire hazards.
Assuming silicon diodes been around for 67 years or so. No need to reinvent the wheel
Common sense would be the rectifier average temp under operation and the thermal threshold of heat shrink.
Regardless it will be under high temp for its lifetime and likely degas and dry out quickly. Doesnt seem ideal
Since i wouldn't want to smell it or worry about fire hazards.
Assuming silicon diodes been around for 67 years or so. No need to reinvent the wheel
@drjb Can you please measure the output voltage of the high-voltage windings of the power transformer? Loaded and unloaded. And DC-resistance of the windings.
Replacing vacuum or selenium rectifiers with Si or SiC can lead to ringing, different output voltage of the rectifier and higher ripple current in the first smoothing capacitor.
Replacing vacuum or selenium rectifiers with Si or SiC can lead to ringing, different output voltage of the rectifier and higher ripple current in the first smoothing capacitor.