Hi,
I have a TEC wine cooler with a board that is very similar to this:

I found a schematics that looks consistent with what I see: (capacitor values, etc.):



The cooler has a hard time to start. Meaning, I see that the LEDs are blinking very lightly and sometimes it successfully starts. Sometimes they just keep blinking and it keeps the "trying to start" state.

When I disconnect the interior fan (CN2) then it starts almost immediately (LEDs blinks for a fraction of a second) but when I connects it back it's having a hard time. Also, when I disconnect the TEC it starts without any issues.

I checked C10 (the usual suspect) and it's ok. I also checked one of the big caps that looked perhaps suspicious (one of the 120uF caps) but it's ok.

Looking at the circuit I suspect C8 or one of the diodes, but I want my next dive in to be analytic, so I ask your help with the evidence I brought.

Thanks!

 

C8 is the usual suspect. Replace it. The symptoms you describe are typical. Did you see the threads here on the issue?

Since the fan load seems to exacerbate the problem, you might want to verify the fan isn't bad. That actually happened with mine. But I'd replace C8 first and see how it goes. Make sure you find a replacement with low ESR, high temperature rating and long lifetime. Pay attention to dimensions - it can probably be taller than the original but it can get hard to replace if the diameter or lead diameter is larger than original.

 

Is C8 the usual suspect of this schematics? I thought that in this one it's the C10, which feeds all the high current devices, and if I recall correctly it is called C8 on other schematics.

Can you please have a look at the schematics I provided?

The fan on CN2 works well, so I suspect it's not it.

Thanks!

 

It's been a while but my recollection is that C8 is 47µF, just as it is in your schematic. My original was rated to 25V but I replaced it with a 35V Panasonic
https://industrial.panasonic.com/cdbs/www-data/pdf/RDF0000/ABA0000C1215.pdf

 

Since the photo of the PCB shown is not yours, post a photo of your board (both sides) so that we can compare the two boards.

 

Thanks!

So I deep dived in my previous situation and it was indeed the same C8 shown here.

I replaced it by a new one and now it works perfectly. Thanks!

I'll post that in the success story thread.

 

Good morning. Thank You for sharing the PCB layout. I lost the existing capacitor. But through this drawing I get the Part values.
Thank you.