Hello guys.
I´ve been reading your posts carefully as I have the same failure in the power supply of my wine cooler: it doesn´t start whn plug to AC, but it does if I disconnect the Peltier module (originally failed, but replaced by a new one!). My PSU looks similar to the ones in the pictures of your posts, manufactured by Foshan Hanyi Computer P/N 0757-83835908. So far , I´ve repalced both transistors 13005, TL494 controller, schottky rectifier, and all the electrolythics. But still not working.

Any idea of what else could fail in this kind of power supplies?

Hope someone could help!
Regards from Argentina,
Sergio

<Moderator's note: Better to start with a fresh thread so you get more views. The referenced pictures are below.>

 

...I have the same failure in the power supply of my wine cooler: it doesn´t start whn plug to AC, but it does if I disconnect the Peltier module (originally failed, but replaced by a new one!).

That's curious. With the module disconnected, do all other functions appear to work? Fans, control panel, LEDs on the PCB, etc?
What is the voltage at the module socket when it is disconnected?
I'd look hard at the module to make sure it can produce cold on one side and hot on the other, and make sure the cold side is facing the right way.

 

Hello guys.
I´ve been reading your posts carefully as I have the same failure in the power supply of my wine cooler: it doesn´t start whn plug to AC, but it does if I disconnect the Peltier module (originally failed, but replaced by a new one!). My PSU looks similar to the ones in the pictures of your posts, manufactured by Foshan Hanyi Computer P/N 0757-83835908. So far , I´ve repalced both transistors 13005, TL494 controller, schottky rectifier, and all the electrolythics. But still not working.

Any idea of what else could fail in this kind of power supplies?

Hope someone could help!
Regards from Argentina,
Sergio

The symptoms clearly point to excessive TEM current drain -- That said I have never encountered a 'shorted' TEM...

To make certian try loading the SMPS with a 'stiff' load exhibiting marked 'inrush' (e.g. an incandescent running lamp bulb)... It's possible that the SMPS has experienced an (isolated) failure of its 'soft start' feature...

Best regards and good luck!
HP

 

Hi, I have the same issue in my wine cooler power source, but in my case one of the components has totally burnt and after read this post I have an idea of which component is, I think is the NTC Thermistor, I see in your photos that the PCB is the same model but the distribution of the components is a little different so I guess the thermistor is the same, can someone give me the part number or the value of the thermistor?

Thank you in advance!

 

I´ve reading comments in this forum and others reporting similar failures as mine (fridge/wine cooler will start withuout peltier cell connected, but not with it connected) and cannot find a reasonable cause for such malfunctioning, yet. I believe we should discard failed components in the "normal working" part of the circuit as it works regularly when the TEC is connected after the PS has started. Rather we should focus on the starting components of the circuit. The question is "what components work when starting the PS?". I´ve cheched the ones associated to pin 4 of TL494 IC, but not find them as failed. More ideas??

Regards,
Sergio

 

Hi, I have the same issue in my wine cooler power source, but in my case one of the components has totally burnt and after read this post I have an idea of which component is, I think is the NTC Thermistor, I see in your photos that the PCB is the same model but the distribution of the components is a little different so I guess the thermistor is the same, can someone give me the part number or the value of the thermistor?

Thank you in advance!

Did you ever happen to find out the model or value of the NTC thermistor? I have the exact same problem as you and mine is also fried to the point of being impossible to get any information from.

 

Did you ever happen to find out the model or value of the NTC thermistor? I have the exact same problem as you and mine is also fried to the point of being impossible to get any information from.

I'm new to the site but did a search for this probel on this board and it lead me to this forum...so, I too am troubleshooting on this same powersupply. The pertier unit was shorted in both directions (replaced), the dual diode driver ic (to220 pk: st2025 i think) was shorted pins 1 to 3 (replaced), and the little 5nF polyfilm cap (green) by the big torroid coil was degraded (replaced). It had also turned from shiny green to dull brown so i knew something wasnt right there. All of the other functions work: board installed and everything hooked up to it, (nothing works) it has a running chirping sound with noise (which i think is a schotky diode whine), but when i disconnect the peltier from the board, the two cooling fans turn on. All diodes check good (in circuit). Im going to do some more t/s today to see if I can find anything else. I will update.

 

This is the Thermistor that was in my board ( p/n: CT7 102K ) right next to the AC power input connector. I replaced it, P/S unit still checks bad. I tried to upload a pic of the component but rejects it, i guess the image size is exceeded.

 

I tried to upload a pic of the component but rejects it, i guess the image size is exceeded.

I think new users are restricted from uploading pictures for a bit.

Are you saying everything seems to be OK as long as you don't attach the peltier?

 

I think new users are restricted from uploading pictures for a bit.

Are you saying everything seems to be OK as long as you don't attach the peltier?

Sort of. Even with the Peltier diconnected, the board has a sound like (like the sound of a diode going bad or a cap/coil resonating) it's stuck in a lower power-on/up state.

 

I think new users are restricted from uploading pictures for a bit.

Are you saying everything seems to be OK as long as you don't attach the peltier?

Tomorrow, I'm going to ring out and check all of the components (pull each individually) that are associated with the soft-start circuit (pin 4, 14, 7, & 5) on the TL494.

 

I think new users are restricted from uploading pictures for a bit.

Are you saying everything seems to be OK as long as you don't attach the peltier?

Okay, an update from today:

I checked the TL494 ic and LM358P opamp chip out. They both function correctly. I replaced the 16V 2200uF electrolytic with a new 35V 2200uF and I found a partially defective/degraded zener diode (DW2). Zener part number is C7V55T (Vrev 7.5V, Irev 2uA, Vfwd, 0.7V, Ifwd 50mA). Its a component of the soft-start circuit for the TL494 (AZ494AP-E1). The closest suitable substitute that I can find thus far is either NTE5121A or NTE5125A.

 

I think new users are restricted from uploading pictures for a bit.

For Zener diode (DW2), I ordered a 1N755A. I ordered two of them, just in case the peltier decides to go "shorted" again. Another suitable Zener we can try if this one doesn't work is the 1N958B. I will post results when the diode come in and sum everything up that I did for the repair with this board so that anyone can easily/readily acomplish it themselves. Oh and BTW, the correct original p/n for the Zener is C7V5ST, not C7V55T as I previously thought.

 

For Zener diode (DW2), I ordered a 1N755A. I ordered two of them, just in case the peltier decides to go "shorted" again. Another suitable Zener we can try if this one doesn't work is the 1N958B. I will post results when the diode comes in and sum everything up that I did for the repair with this board so that anyone can easily/readily acomplish it themselves. Oh and BTW, the correct original p/n for the Zener is C7V5ST, not C7V55T as I previously thought.

 

Any update on this? Exactly the same failure with chirping sound and board working fine after peltier disconnected. I have a dual zone and connected the other peltier and does exactly the same so is the board

 

Hi everyone, I have the same issue. Board doesn't start unless I disconnect the Peltier. Is it the board or should I swap the Peltier?
Thanks!

 

You can test the Peltier TEC independently from the PSU (power supply). Find the voltage and current rating of the TEC and run it at half the wattage for a few seconds. If it heats and cools then you may assume that the TEC is ok. In which case the problem is in the cooler's PSU.

 

Any update on this? Exactly the same failure with chirping sound and board working fine after peltier disconnected. I have a dual zone and connected the other peltier and does exactly the same so is the board

Hi everyone, I have the same issue. Board doesn't start unless I disconnect the Peltier. Is it the board or should I swap the Peltier?
Thanks!

Be sure to skim the related thread:
https://forum.allaboutcircuits.com/threads/success-stories-repair-thermoelectric-cooler.101748/

It's grown quite large and the main message is: Replace the electrolytic capacitors, particularly C8 in the power supply. I don't know if it's referred to as C8 on every board, but definitely for many. If you have no way to test the capacitors for ESR, it's easiest to just replace all of them. Only one freight charge on your parts order.

 

That thread has all the information someone could need, I'll be reading it for the next couple of hours

Exciting to get a Reply from the OP himself, thanks @wayneh !!!

 

Hi from Romania
I've read the topics about those peltier coolers but mine still not working with peltier conected. Board FX102, PCB12111OK1, 230V, 12,5V.
First of all fuse blown and two bad diodes from rectifier. All 1N4007 new + almost all electrolitic condensers changed (less 2 big ones 120u/200V). Then two transistors on heatsink new (130005A) + 2 resistors (2,2ohm insted of 2ohm). Also two small transistors new SC1815. Now source is working with both led on but when I connect the peltier is making a hissing noise and only the red LED lights shortly from time to time. I tried with a new peltier same situation, I put a 2,2ohm resistor in series with peltier also same situation. I don't know what to try next.