RT on 0757-83835908 Wine Cooler Power Supply

Thread Starter

johnmanzi

Joined Mar 5, 2017
6
Hi
I'm troubleshooting a Wine Cooler Power Supply with part number 0757-83835908. I see several threads on similar boards but mine has a different configuration than those shown in the photos. Any way, here's my problem
There is a device is series with the fuse and looks like a disk shaped ceramic capacitor but I think it's a surge protector. It is labeled RT- perhaps Resistor Temperature sensitive? It is open circuit so it's no wonder the PS doesn't turn on. Anyone have any idea what to replace it with I don't have any clue as to what range of Hot/Cold resistance values I need.
Thanks,
John

PS - While I was at it, I figure I ought to replace the two big (220 uF, 200V) caps near the input,. Any suggestions for any other parts I should considering swapping out before I power it up, assuming I find something to replace RT?.
WineCooler1.JPG
 

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Dodgydave

Joined Jun 22, 2012
10,583
It's a 12V @6amp switchmode psu, with an inrush ntc resistor, if it's open circuit then it's probably blown, are there any markings on it?

You can check with a dvm on Diode test the bridge rectifier diodes at the bottom of the picture between the two transformers, and across the two electrolytic caps for shorts.
 
Last edited:

MaxHeadRoom

Joined Jul 18, 2013
26,241
Are you sure it is a NTC res and not a MOV, these are typically across the input supply generally measure high resistance on a meter.
Both usually show signs of over heat, if shot.
SMPS supplies are very cheap, if you need to replace.
Max.
 

Thread Starter

johnmanzi

Joined Mar 5, 2017
6
It's a 12V @6amp switchmode psu, with an inrush ntc resistor, if it's open circuit then it's probably blown, are there any markings on it?

You can check with a dvm on Diode test the bridge rectifier diodes at the bottom of the picture between the two transformers, and across the two electrolytic caps for shorts.
There are no markings just a round green disk. It is definitely in series with the fuse to limit in rush current. It's an open circuit. I just don't know what cold/hot resistance values I need to replace it.

The bridge rectifier diodes all ohm out good. The caps seem ok in circuit but I don't know about leakage
 

Thread Starter

johnmanzi

Joined Mar 5, 2017
6
Are you sure it is a NTC res and not a MOV, these are typically across the input supply generally measure high resistance on a meter.
Both usually show signs of over heat, if shot.
SMPS supplies are very cheap, if you need to replace.
Max.
Thanks Where can I buy a replacement?
 

Thread Starter

johnmanzi

Joined Mar 5, 2017
6
You know a little about the power supply and they are "in-rush current limiters": https://www.ametherm.com/inrush-current

You can make an educated guess based on size and steady state current and max current.

They can act as a fuse too, so your problems are not yet solved.
Thanks to all for the help.
Ordering some inrush limiters and caps from Digikey. I'll report back when they arrive and I try them out.
Thanks again,
John
 

Thread Starter

johnmanzi

Joined Mar 5, 2017
6
Thanks for all the help.
I bought a inrush limiter from Digi Key and a couple of caps. Only replaced the inrush limiter an IT WORKED!

Thanks once again to everyone for the help,
John
 

jp2019

Joined Sep 9, 2019
1
Thanks for all the help.
I bought a inrush limiter from Digi Key and a couple of caps. Only replaced the inrush limiter an IT WORKED!

Thanks once again to everyone for the help,
John
I have a similar problem. It would a help a lot a beginner like me if you shared a link or description of the inrush limiter you purchased? Thank you very much in advance.
 
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