PG108RH rectifier diode. I'm reading .052V in either direction. Unless i missed something, it's bad.
What are my alternatives to replace?
What are my alternatives to replace?
Here's a guess at a substitute:
First link is to a data sheet for the failed diode.
Second link is to the diode I'd try. It has similar current, voltage, capacitance, and quicker reverse-recovery time than the original.
Third link is the search criteria I set as an aid to find the suggested part. Many of these parts will probably work.
Good luck!
PG108R pdf, PG108R description, PG108R datasheets, PG108R view ::: ALLDATASHEET :::
Blocked
Blocked
First link is to a data sheet for the failed diode.
Second link is to the diode I'd try. It has similar current, voltage, capacitance, and quicker reverse-recovery time than the original.
Third link is the search criteria I set as an aid to find the suggested part. Many of these parts will probably work.
Good luck!
PG108R pdf, PG108R description, PG108R datasheets, PG108R view ::: ALLDATASHEET :::
Blocked
Blocked
Two of the three links show as blocked but seem to work when I click on them. Let me know if they don't work for you.
The actual part is UF2007 TR from Central Semiconductor.
The actual part is UF2007 TR from Central Semiconductor.
A friend got back to me and said he got o52 in both directions on a god one so i'm guessing I have a ways to go still.
Aha! I surmise the circuit has DC continuity surrounding the diode. Can you poke around with an oscilloscope?
Good luck!
Good luck!
If you are testing the rectifier in-circuit you may just be measuring the resistance of a transformer winding.
I removed the diode completely before measuring as I always do with diodes. I looked at the specs but I don't know how to relate them to what I am looking for. I do see a forward voltage like other diodes but I don't want to get ahead of myself.
I just double checked. I get 0.052 volts in both directions under a diode test with my meter. I decided to check resistance as well. 83.4 ohms in either direction. regardless of the value I'm getting, that doesn't follow the definition of a diode so maybe I am heading in the right direction.
There is no issue, the diode has failed. Diodes under a bit more stress than they can handle fail by shorting as yours has. When hugely overloaded they blow open.
When a failed diode has blown open, the wise will use a current limiter and check to find what else is bad. As yours has failed shorted a brief power application would be a suitable first test. Looking at the output during that quick test should allow you to see if the DC output rises to normal indicating far fewer worries. After the DC drops and the AC line is disconnected a finger test might show anything that is heating up.
Of course you might want to check the other diodes!
When a failed diode has blown open, the wise will use a current limiter and check to find what else is bad. As yours has failed shorted a brief power application would be a suitable first test. Looking at the output during that quick test should allow you to see if the DC output rises to normal indicating far fewer worries. After the DC drops and the AC line is disconnected a finger test might show anything that is heating up.
Of course you might want to check the other diodes!
I have a couple of other similar fast acting rectifier diodes on hand from other SMPS. which values am i looking for?
The original diode had 800V reverse breakdown rating--- to be conservative you should have at least that or more. Again at least 1Amp or greater current. Recovery time and capacitance are probably more forgiving parameters.
A Variac should work for trouble shooting but switcher will behave oddly at reduced supply voltage.
Good luck again!
A Variac should work for trouble shooting but switcher will behave oddly at reduced supply voltage.
Good luck again!