Yet another blown power supply capacitor, please...

Thread Starter

danl

Joined Sep 24, 2013
60
I did search and found so many different posts, but none specific to what I have.
What is the likely replacement for this blown capacitor, please?
Specific info in the 3 attached pics.
Black arrow shows where the capacitor was located.
Thank you for any help.

20220510_171049.jpg20220510_163748.jpg20220510_171049.jpg20220510_163748.jpg20220510_171049.jpg20220510_164704.jpg20220510_163748.jpg
 

Thread Starter

danl

Joined Sep 24, 2013
60
Thanks. Right...I see the RT1 on the board now.
Searched and found that NTC is a negative temperature coefficient resistor.
" NTC is a resistor with negative temperature coefficient, used for temperature measurements or inrush current limiting (high resistance when cold, warms up at current flow an decreases resistance)."
So I assume its for inrush current limiting?
Attempted to measure R across what remains of the leads - get about 600ohms- but the part has been fried. Highest NTC 15 (15mm dia) I could find is 120ohms, 2A Imax.
Is there atypical value I can use here for this PS (specs on label pic)?
 

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Thread Starter

danl

Joined Sep 24, 2013
60
Thank you for pointing out that it is an NTC. I found a link to repair a 12VDC 30A power supply (vs my 24v 20A) using an NTC 5D 15. I should be able to figure out what to use. If someone has the answer already, that would help.
Thanks.
 

sagor

Joined Mar 10, 2019
914
A 500W power supply would need a NTC that passes at least 4A to 5A, possibly a bit more. Note that the fuse is 6.3A itself...
Your picture shows a part ending in 15, that is the diameter of the NTC but no actual resistance or current rating is legible.
There are NTC in that range that can handle at least 5A (for example) like 6D-15, 7D-15 up to 12D-15. The "D" number represents the initial resistance.
For more current, the 5D-15 will handle 6A, 3D-15 will handle 7A
A "-20" NTC will handle a bit more current for the same "D" rating (ie: 6D-20 will handle 6A)

If the NTC keeps blowing, then you have some other serious load/shorting problem.
 

Thread Starter

danl

Joined Sep 24, 2013
60
Sagor...thank you very much.
I am going to try this one:
NTC Thermistor Resistor 8D-20 6A 8 Ohm
From uxcell/Amazon
Sound OK?
The power supply worked well for 3 or 4 years. Seemingly no problem until the NTC blew when the PS was turned on. Maybe just age related.
 

sagor

Joined Mar 10, 2019
914
The -20 size should be ok, if the holes match (otherwise you have to bend the leads a bit). Not sure about the initial 8D value however. Higher start values have a higher "running" resistance once it drops, and thus more heat generated. But, without knowing if the original was 3, 5, 6 or 8 ohm, it's all a guess anyway.
 

sagor

Joined Mar 10, 2019
914
Sagor...thank you very much.
I am going to try this one:
NTC Thermistor Resistor 8D-20 6A 8 Ohm
From uxcell/Amazon
Sound OK?
The power supply worked well for 3 or 4 years. Seemingly no problem until the NTC blew when the PS was turned on. Maybe just age related.
This schematic for a 240W PSU shows a 5D-15 NTC in the circuit: (similar to yours)
https://electronics.stackexchange.com/questions/534309/switching-power-supply-repair

That one has a 5A fuse, and a 5 ohm NTC...
 
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