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
 

Attachments

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
2
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.
 

Pacobeagle

Joined Sep 5, 2020
1
This has got to be the find of the year! My neighbor was going to throw away an 18-bottle Wine Enthusiast cooler (with two FX101 boards) and I was lucky enough to ask if I could have it before it ended up on the curb. A quick search on the web and I came across this wonderful forum with plenty of information. I, like many others, had the issue of no display, constant beeping while connected and no fans. Circuitry looked to be in fair shape, fuses were good just completely covered in dog hair. Having a 65-gallon air compressor, I decided to blow out as much of the dog fuz as possible. From there, the only way to get everything to work was to remove the (-) cable from the TEC unit and it would come to life.
However, knowing that would not last I attempted a "trust but verify" repair. It was then I took the C8 and swapped it with another similarly spec'd capacitor on the board. At this point, I re-installed the board and connected all wires. VIOLA! It's been running since this morning. Both fans and respective LEDs are on and the front display is operational (currently displaying 54-degrees).
This confirms, as many others have, that C8 is critical to the operation of the system. At the moment, I have spent a total of several hours reading/researching and 30 minutes swapping the capacitors. If it doesn't last, I'll order all capacitors.

Again, thanks to all who have helped contribute.

v/r,
J. Martinez
 

reshuman

Joined Jul 27, 2020
2
This has got to be the find of the year! My neighbor was going to throw away an 18-bottle Wine Enthusiast cooler (with two FX101 boards) and I was lucky enough to ask if I could have it before it ended up on the curb. A quick search on the web and I came across this wonderful forum with plenty of information. I, like many others, had the issue of no display, constant beeping while connected and no fans. Circuitry looked to be in fair shape, fuses were good just completely covered in dog hair. Having a 65-gallon air compressor, I decided to blow out as much of the dog fuz as possible. From there, the only way to get everything to work was to remove the (-) cable from the TEC unit and it would come to life.
However, knowing that would not last I attempted a "trust but verify" repair. It was then I took the C8 and swapped it with another similarly spec'd capacitor on the board. At this point, I re-installed the board and connected all wires. VIOLA! It's been running since this morning. Both fans and respective LEDs are on and the front display is operational (currently displaying 54-degrees).
This confirms, as many others have, that C8 is critical to the operation of the system. At the moment, I have spent a total of several hours reading/researching and 30 minutes swapping the capacitors. If it doesn't last, I'll order all capacitors.

Again, thanks to all who have helped contribute.

v/r,
J. Martinez
Glad you got it working. I think the major issue here is with the 25V capacitors. They probably should have used 50V caps in this design. They are dirt cheap and easily replaced on these boards.

Bob
 
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.View attachment 213695

Another data point suggesting that the C8 capacitor (25v47uF) is a common issue for these boards. Should also inspect for other issues.

I picked up a non-functional Koldfront TWR121SS for free. The board (TWR282S/ TWR160S/ TWR121SS Circuit Board) is very similar to this board posted by maheath. Upon close inspection, I found that the large cap C12 had leaked, and its removal revealed brown corrosion underneath, and one of the leads from C12 easily pulled out. I replaced both C16 and C12. When I plugged the board in, I found that the hot fan and TEC started up when I tapped the NPN transistor heat sink! When I tapped the heat sink again...I got shocked! When I grounded the heatsink to green AC ground, it triggered the GFCI outlet this was plugged into (duh. later determined the collector of the NPN is connected to the heat sink). Then, the issue was similar to what others had--TEC powered only if connected after the unit is powered. I replaced both NPN transistors and their heat sinks (a newer but incompatible board from the manufacturer I was pulling parts from contained similar transistors but taller heat sinks, so I assumed it would be an "upgrade"). Upon removal of the NPN closest to C12, I noticed that the PCB trace connectors for that NPN had delaminated/corroded from the board (I presumed it was due to corrosive juices from C12 cap leakage flowed downward to the NPN). I resolved it by scraping the PCB to expose the copper further away from the mount holes, and making a larger solder joint as needed. This replacement did not resolve the TEC power issue. I replaced C10 (16v1000uF) (because it is the closest to the TEC), then C6 (25v47uF) (because others identified the 25V47uF caps as issues) sequentially still yielding no apparent change. Finally, I changed C8 (25v47uF), which resulted a full functioning unit.
 

speeder

Joined Sep 21, 2020
3
I have a 3yo Newair single-zone cooler with a 12.5v FX-101 board that stopped cooling properly. The TEC voltage is 7v. I checked and replaced a few 47uf 25v caps (C8 and CA1) but the original caps were fine (50uf). Any ideas what else is worth checking?
 

speeder

Joined Sep 21, 2020
3
looks like i can't edit my post. Fans spin low. NTC1 shows 10.2kohms which seems to be correct, about 75* F. Red LED loses intensity. Starting up with TEC disconnected spins the fans up and the red led remains pretty bright.
 

MrAl

Joined Jun 17, 2014
11,389
looks like i can't edit my post. Fans spin low. NTC1 shows 10.2kohms which seems to be correct, about 75* F. Red LED loses intensity. Starting up with TEC disconnected spins the fans up and the red led remains pretty bright.
Hi,

What kind of power supply is it, linear or switching?
I am not familiar with that model.
 

speeder

Joined Sep 21, 2020
3
i have a fx-101 12.5v board. i checked all 25v 47uf and 2000uf caps, they're all in spec, good ESR. going to look for a new board instead of trying to track down what other component it may be.
 

cdemke

Joined Sep 26, 2020
1
Success!!! I recently purchased a used Koolatron 6 bottle wine cooler for $45 on offerup.com. It worked great for about 3 days, then the display started acting erratic along with a repeating chirping sound as if I was constantly pushing the buttons. I figured my $45 was wasted until I started googling the problem and came across this thread. My cooler has the fx-101 10.5v board. It would power up with the TEC disconnected, etc, all of the typical symptoms mentioned here. I do not have a capacitor tester so I purchased a 240 piece capacitor pack from Amazon along with a soldering iron kit, total cost $25. I replaced all 13 electrolytic capacitors on the low voltage side. Unit has been working for a week now!
Interestingly my C10 was 2200uf, not 1000uf like some posts have mentioned. Could someone have replaced it before me in an attempt to repair the unit???
Anyway, thanks for the great info! This was a fun project and my investment is still in the black as a new unit sells for ~$150-$200.

Chris
20201005_071910.jpg
 
I always say before I take something apart, I will take pix first, and never do. I have a 6 bottle cooler with a FX 101 board.
I replaced the Peltier module, and believe I put the black TCM sensor on the hot side in error as there was a slot on the bottom of the stryofoam surrounding the module, but nothing else apparent to indicate placement. (Posts #125, 214 helped show me the error.):mad:The TCM is not mentioned in the Youtube DIY videos.

Can anyone advise the proper placement on the cold side?
 
Found a hole in the side of the cold side heat exchanger, perfect for the TCM sensor. Unit seems to be working now.
I am now an expert at changing out the Peltier module.

It is a 2007 unit, from the WSJ Wine Club, and has given good service far longer than the average, apparently.

Many thanks to this forum for pointing the way to a solution. If or when my circuit board melts down, I know what to do....
 

hueypic

Joined Sep 12, 2017
9
I have one more question to add to the thread....
One of the circulating fans on the inside of my fridge has a bad bearing. Its marked as a TX8020L12S, but I cant decide what I should replace it with.
There probably isnt a "wrong" answer (as long as the 12V is right) but its a tradeoff between noise and effectiveness. Its a fairly quiet unit anyway.
Is it variable speed, and all I need is to make sure I get something that will go max? As things are more efficient these days, I'm sure anything even close to the ma rating of 80ma is going to be fine.
It doesnt have to do much, just move air over the TEC and into the cabinet, so might be very low CFM....
 
I believe that the rear exterior fan varies in speed based on requirements, so I'd assume the internal one does the same, as controlled by the circuit board.
 
I had the same problem with the wine cooler and it was capacitor C8. All the other caps were OK. It apparently is in the circuit with the thermo module which draws current with C8. There were two of these circuit boards in the fridge so I replaced both with a 47uf 50 volt 105 degree instead of the 25 volters that were originally installed. Unit works perfect now.
 
Top