Hello - first post and relatively new to circuit repair so thanks in advance for any assistance. I am having an issue with my Edgestar TWR325ESS wine cooler. The fuse blew on the left control board and immediately blows again when replaced so I'm assuming a short. I removed all four fans and the two cooling blocks and checked their resistance and none showed zero resistance (the fans were ~3 Ohms, the cooling blocks were ~15 Ohms if I recall correctly). I unplugged the fans, cooling block, and NTC sensor from the board and replaced the fuse and the fuse still blew when I turned it on. I purchased a new control board, installed it, and the fuse immediately blew when I turned it on (I know, I know...)

At this point, I'm completely lost. I measured 120V on the input from the power cord and don't know what else to do to diagnose. I don't understand how there is a short if the board is plugged into only the power and nothing else. Is there some other component that I am not clear on which is causing the short? Were components on the board damaged that now cause it to blow the fuse every time? How do I identify them and replace them? Any and all help is appreciated. Thanks!

Manual: https://www.edgestar.com/on/demandw...1c/support/manuals/TWR325ESS_ownersmanual.pdf

 

I couldn't find any schematics for the circuit boards in this unit but you might watch the video below, especially from about 18 minutes in, which suggests that if you replace one board you should replace both boards.

 

I couldn't find any schematics for the circuit boards in this unit but you might watch the video below, especially from about 18 minutes in, which suggests that if you replace one board you should replace both boards.

I have previously viewed the video and just re-watched it - the advice: re replacing both seemed to me to stem from an expectation that if one went out, the other would likely fail as well. He seems to indicate that the left board powers the right board but I have entirely unplugged and removed the left board and the right one continues to operate just fine.

 

Does the right board work the cooler, with correct LEDs on the board and no error code showing on the front?

 

Does the right board work the cooler, with correct LEDs on the board and no error code showing on the front?

Yes - the right board appears to be operating perfectly. There are no error codes and that half of the cooler is at the correct temp with the front display working correctly.

 

And it is the fuse on that left board which blows, not a fuse elsewhere?

 

And it is the fuse on that left board which blows, not a fuse elsewhere?

Correct. I'm only aware of fuses on the two boards.

 

This is a replacement board?
When you fitted it originally, was everything connected?

 

This is a replacement board?
When you fitted it originally, was everything connected?

Unfortunately, yes. I realized the mistake the second I did it although I had tested the components that were plugged in (4 fans, 2 cooling blocks - the NTC sensor is apparently no longer needed with this new board) so I had confidence that they weren't causing the short. Unfortunately, as I've read more on this forum I'm realizing my testing skills may not have been sufficient.

 

the NTC sensor is apparently no longer needed with this new board

I don't see how that is possible as the NTC is how it measures the temperature so without it the board can't control the temperature.
Mind you, it still shouldn't blow fuses.

 

Can you take a good close, clear picture of the left board.
Actually can you make that pictures of both boards.

 

Can you take a good close, clear picture of the left board.

I'll take a picture of both the left and right boards tonight and upload them. Agreed on the NTC sensor - the new board included an insert stating the board had been redesigned and that it was no longer necessary. I fail to understand how it would still function.

 

This thread might have some information or ideas for you.
https://forum.allaboutcircuits.com/threads/repair-thermoelectric-cooler.101748

 

This thread might have some information or ideas for you.
https://forum.allaboutcircuits.com/threads/repair-thermoelectric-cooler.101748

Thanks - based on that thread, it sounds like replacing the caps on the blown board might get it working again. My question is how did a brand new board blow a fuse immediately upon installation? To me, that points to a short but, as I mentioned, I tested the fans and cooling block for resistance and they had values (although I don't know what the expected values should be). I'll post photos of the board tonight and keep working at it...

 

I would expect any such power supply to include current limiting so even a dead short on the output shouldn't cause any damage. But without a schematic I can't confirm that this board does have current limiting

 

I kind of doubt it. Mine had a fan go bad and that brought it down. For schematics check out the linked thread. No guarantee it applies to this unit but maybe a photo would help confirm.

 

Left board photos. It's clear that at least one of the caps is bad and will need to be replaced.

 

Right board (working) photos

 

On the left board, what's on the heatsink near the mains input?

 

Sorry - I'm not clear what you are referring to. Looking at the heat sinks I don't see anything that stands out - can you please be more specific?