SUCCESS STORIES: Repair thermoelectric cooler

BobF1

Joined Jul 5, 2020
3
Hello everyone,
Such a great thread, big thanks to Wayneh for starting back in 2014, a great run so far. Also thanks to 5haggy for the list of parts with links, super helpful and to Jay Miller for the PCB photo with cap specs. And to all who have contributed along the way, I've been having a blast with this.
Now on to business. I have a Frigidaire with 2 fx-101 boards and have the similar issue as stated prior. Plug it in nothing works. Unplug the TEC from the top board and everything turns on. Lights inside, fans and the LED's. Prior visual inspection of the large caps (120uf 200v) showed some melting of the cover so I ordered replacement. Question - the replacement caps have same capacitance but the size is not the same. See picture below. Does anyone see this as an issue over time?

By the way, that didn't resolve the issue. I ordered all replacement caps and will start with the c8 as recommended.
Thanks all
 

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HaroldTX

Joined Jul 11, 2020
1
Another success! First off, I would like to thank all of the contributors to this subject. This made my repair go very smoothly! My Danby 12 bottle wine cooler, DWC1233BL-SC, failed after 5 years, intermittently not restarting after a power failure. I found a visually leaky output cap, C10 1000uF 16V, and replaced it. C10 was the only cap that looked bad. It worked for a couple of weeks and then went really dead. That’s when I found this forum. Finding the schematic was a happy bonus!

One of the input transistors, T6, was shorted. Following the recommendations, I pulled all the electrolytic caps and checked them. Except for three, all were within 20% capacitance tolerance, but nine had bad ESR and the rest were marginal. For instance C8 had an ESR of 53 ohms. I ordered all the caps with bumped up voltage ratings and 10k hour life, and both of the primary transistors from Mouser just for insurance. Installed them yesterday along with a pi filter on the output to the thermoelectric with an additional 1000uF 25V. All is good!

I replaced the 80mm external heatsink fan with a 120mmm for a little more cooling, added an additional 80mm fan to blow across the PCB and glued two small heatsinks to the board’s secondary heatsink to help there as well. The second fan might be overkill and did add a little more fan noise. I might remove the second fan later if the added noise begins to bother me.

Last night I set the temp down as far as it would go, 50F, and loaded it up. This morning it was running at 53F with a 75F ambient. IDK if that is normal for this cooler because I usually run it at 55F anyway. I’m happy with it for now. Hope it lasts a long time! Now, if I could only find a replacement for the front panel segmented display that’s missing a couple of segments.

Thanks again to everyone!


Original Configuration.jpgPCB with Parts Removed.jpgcompleted wine cooler mods.jpgWine Cooler PCB Mods.jpg
 

reshuman

Joined Jul 27, 2020
1
I wanted to post a note to let the original author and previous contributors to this (now fairly lengthy) thread know that they have another success story to add to the list. The peltier thermoelectric in my case was manufactured by "Wine Enthusiast" and is model #272 (272 0319 05). It is a dual compartment wine cooler that uses the exact same design as all the other units described earlier in this thread. This wine cooler was received as a wedding gift by my son and his wife just about 5 years ago (seems to be a common failure interval). When I was asked to look at it Sunday, both of the cooling compartments had stopped not working. Initial analysis showed that both front digital displays and controls seemed to be working correctly, but none of the 4 cooling fans were operating and the units were obviously not cooling.

FYI, this unit uses a slightly different (perhaps newer? but if so, definitely not better) PCB than the FX101 and FX102 others had fixed, but after looking at the photos in the thread and the power supply schematic (thanks so much for finding this), I decided it was ~95% similar. Taking some test voltages, I observed that there was + and - 165 VDC on each of the supply side (200V) Electrolytic capacitors and there was 5+ Volts (as expected) on the connector going to the front controls/display. The 12VDC output was basically zero, so this is why the fans and coolers were not working.

After reading this thread, I verified the supply side fuse on each board was good (no secondary fuses on this design) and looked for any type of damaged, bulging, or leaky components (I found none). Based on the success of others, I went ahead and replaced all 13 electrolytic capacitors on the LOW VOLTAGE side of the PCB. (Note that I did not replace either of the large 200V electrolytic caps since they seemed to be working OK and their ESR checked out as expected using my ESR meter.) After carefully replacing all 13 capacitors, verifying continuity, verifying no shorts, and cleaning up the solder rosin residue, I re-soldered the peltier cooling unit connections and put the unit back into the cabinet. After plugging it back in I was pleasantly surprised to see the lower chamber was now working perfectly.

I then bench checked the ESR on all 13 of the capacitors I had removed/replaced. I found 4 of the 13 to be way outside expected readings (one, the 47mfd cap was actually reading 80 ohms). To help others, the 4 bad capacitors on that 1st power board were: 47mfd, 25V (Qty 1), 100mfd, 25V (Qty 2), and 1000mfd, 16V (Qty 1). So based on this new information, I decided to try to replace only these 4 capacitors on the second power supply (for the upper wine cooler chamber). The good news is that after replacing just those 4 caps and then reinstalling the PCB, both chambers worked perfectly.

Thanks again to everyone who has contributed to this thread. It allowed me to save this unit from the junkyard since the replacement PSUs would have cost over $150 each (2 required) making it cost prohibitive to go that route. I am not sure why these capacitors fail so early. I am hoping the replacements will last more than another 5 years. I guess time will tell.

Bob
 

maheath

Joined Jul 18, 2020
1
Another Success Story and many thanks to the contributors on this thread. My power supply board was not the FX-101 or FX-102. My board is a HYS60-12-KD. It uses a different list of capacitors, but I documented which ones were on the board and what I replaced them with. I was a little handicapped because I have a dual-zone unit built-in to a nice movable cabinet. Twin Star is the manufacturer. I couldn't find replacement boards and I didn't want to have to find a new wine fridge that might fit in the cabinet. It holds 28 bottles, 16 in the lower zone, 8 in the upper. It says it was built in 2012. I think I acquired it in 2015 at an estate sale. Until now, I'd only had to replace one fan that had a bearing going out.

Neither power supply appeared to be working and the inside of the fridge was room temperature. After reading this thread, I replaced all of the electrolytic capacitors on the upper board. Funny thing, when I re-installed the fixed power supply board, the bottom unit started working again. So I have a complete set of 14 capacitors waiting for the lower board to fail. The fuse was fine. Again, a big thank you to everyone here.

I lifted this picture from the internet.c700x420.jpg

My two power supply boards are identical. I've labeled the electrolytic capacitors on this boardDSC_0157.jpeg

This is a listing of the capacitorsScreen Shot 2020-07-31 at 11.03.09 PM.png
 

L27LB

Joined Aug 2, 2020
1
Thanks for all your invaluable help. I follow the recommendation of changing all the capacitors but did not changed 1000uF@25v, 120uF @ 200v, and 220uF @ 25V. The little Emerson wine cooler is working and cooling as expected. Thanks again for your generosity to put this blog together.
 
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