Problem with overheating in a DC-DC converter

[farsey09]

Hi. I have a problem with my circuit that I hope someone could help me with. =\

I have built a data-logger unit using a picaxe28X that communicates/transmits via a MAXIM485 to another picaxe28X. The unit uses a Mean Well dc-dc converter, SPR01N-05, to step-down 24V power supply to 5V for the data-logger unit circuit. The unit has been logging well except occasionally, the unit losses its operation suddenly. At that point, I measured the input of dc-dc converter and it read 24V, but the output only read approximately 2.5V, instead of 5V. I then cut the 24V power and repower the circuit. The unit works fine again. Once in a while the problem pops back again.

Im guessing that something could have possibly cause an overload to the dc-dc converter, but Im not sure if Im on the right track.

Please help.

 

[Miguel Gaspar]

dc-dc converter

It's difficult the disgnose but it seem that the voltage regulator protects itselt, so when you shut down the power supply and reestart, the circuit get back to work.

another thing put a heat sink to the maxim485.

 

[farsey09]

Re: dc-dc converter

Thanks for the quick reply! The fault has just happened again when I was reading your reply a short while ago.

I've managed to measure the temperature of the components on the board. The dc-dc converter gave a reading of 70degC(!!), while the other components such as picaxe, transistor, max485 and relay read between 20-25degC.

Heatsink would probably help, but Im really curious what has caused the possible overloading on the converter which prompted the converter to protect itself and shuts off.

=\

 

[Miguel Gaspar]

dc-dc converter

So is a over heating problem, search for a short circuit.
Use a heat removal and if the problem continues, it will probably a bad max485 or a short circuit.
Try another max485 if the probelm persist there is a short circuit.

 

[farsey09]

Re: dc-dc converter

Hello. Thanks a lot for your replies.

I have been doing some thinking, and I will look for short circuits on the board. As I built all the units by hand, short circuits could easily be one of the causes although this problem has only started to pop up 6 months into operation. Besides that, other units are still working fine up till now. Otherwise, I will replace the max485 or converter and see if that would help.

thanks a lot!!