I fired up my new power supply, a very basic model, Rapid 85-1901, shorted out the outputs to set the limiting current, the supply made a humming noise and died, this blew the 5amp fuse. Now it blows 5 amp fuses directly on being switched on with no output leads in place.
I think I followed the proper procedure for setting the current, I can only assume I somehow drew too much current and blew the fuse and something internally too. I did use a pair of probe leads joined with a crock lead to short the outputs, though I find it hard to believe this would drop enough voltage to pull meaningful current, but I have been wrong before.
I would be pleased if anyone could help out, I am also interested in trying to repair it and any clues where to start on the board would be appreciated.
Many thanks

 

You set the current properly.
Apparently the supply was not well enough designed to tolerate the short circuit.

Do you have a schematic of the supply?
Difficult to troubleshoot without that.

 

Welcome to AAC!

I fired up my new power supply

Is it still under warranty?

 

That supply has been discontinued by Rapid, I wonder why...

I've been using a general purpose 0-30V, 5A PS as one of my benchtop supplies for many years, the same (looks the same at least) is tagged as a PS-3005D under the Wavecom and other brands. It has been excellent for the last 10 years...

 

You set the current properly.
Apparently the supply was not well enough designed to tolerate the short circuit.

Do you have a schematic of the supply?
Difficult to troubleshoot without that.

Many thanks for the reply, I don't as yet have a schematic but I will be looking for one. I did start on reverse engineering it but it is quite complex

 

That supply has been discontinued by Rapid, I wonder why...

I've been using a general purpose 0-30V, 5A PS as one of my benchtop supplies for many years, the same (looks the same at least) is tagged as a PS-3005D under the Wavecom and other brands. It has been excellent for the last 10 years...

 

Welcome to AAC!
Is it still under warranty?

Hi many thanks for the support, no the supply came from a friend's attic I think it has been sat for some time. I'm more curious about the possibility of a fix for the interest and to see if I made a mistake with it.

 

That supply has been discontinued by Rapid, I wonder why...

I've been using a general purpose 0-30V, 5A PS as one of my benchtop supplies for many years, the same (looks the same at least) is tagged as a PS-3005D under the Wavecom and other brands. It has been excellent for the last 10 years...

Hi, many thanks for the support. Indeed the design looks to be badge-engineered by quite a few vendors, not sure if there were any major updates that were needed.

 

I fired up my new power supply, a very basic model, Rapid 85-1901, shorted out the outputs to set the limiting current, the supply made a humming noise and died, this blew the 5amp fuse. Now it blows 5 amp fuses directly on being switched on with no output leads in place.
I think I followed the proper procedure for setting the current, I can only assume I somehow drew too much current and blew the fuse and something internally too. I did use a pair of probe leads joined with a crock lead to short the outputs, though I find it hard to believe this would drop enough voltage to pull meaningful current, but I have been wrong before.
I would be pleased if anyone could help out, I am also interested in trying to repair it and any clues where to start on the board would be appreciated.
Many thanks

Thanks, everyone for the prompt comments, always nice to get some support in a new area
much appreciated

 

I'm more curious about the possibility of a fix for the interest and to see if I made a mistake with it.

Open it up and do a visual inspection to see if anything is noticeably damaged. In any case, you're going to need to trace the circuit and create a schematic before anyone will be able to help you. If something is damaged, that would give you a good starting point.

 

Is this the psu in question?

 

Next time you want to set a current, turn the current all the way down before shorting the leads. Then turn it up slowly.

Bob

 

That supply has been discontinued by Rapid, I wonder why...

Probably because it was a poorly made Switch Mode PSU? I have 3 of these now. Nothing fancy but 30VDC/5A linear designed with both Voltage and Current limiting if desired. Settable to 1mV & 1mA. Solidly built and not a bad deal for the 85USD price. Maybe even cheaper elsewhere. So far, I haven't found a need for uV or uA level power supplies.

 

Open it up and do a visual inspection to see if anything is noticeably damaged. In any case, you're going to need to trace the circuit and create a schematic before anyone will be able to help you. If something is damaged, that would give you a good starting point.

Hi, many thanks for your comments, there are no clear sign of any issues internally, no burning or blown caps etc
I did find the manual and schematic
https://www.manualslib.com/manual/897687/Manson-Engineering-Industrial-Nrp-3630.html?page=8#manual

The CC setting process is specified as set 3v and then short the output to set the current limit. I had voltage the 12v I think.
Does this sound like the error that may have caused the failure?

 

Next time you want to set a current, turn the current all the way down before shorting the leads. Then turn it up slowly.

Bob

Many thanks for the comment, please see my other reply with respect to the CC procedure "with a 3v preset".
Do you think think the non-zero current before shorting is a"sensible precaution" or a "must" to prevent a failure?

Thanks again

 

Is this the psu in question?

Many thanks for your reply
That supply looks very similar and I think that vid will help me, I did find the schematic for mine, please see my other reply

thansk

 

This is not your psu , yours is a switchmode type, using a TL494 chip.
Measure the voltage at pins 14/7 to see if it's working.


Can you post any pictures of the pcb?

 

This is not your psu , yours is a switchmode type, using a TL494 chip.
Measure the voltage at pins 14/7 to see if it's working.

Can you post any pictures of the pcb?

Many thanks
Attached is what I believe to be the correct schematic for my supply 20V 5A (Manson NSP2050) the board I think is common to the (Manson NRP 3630) 36V 3A, as my board is marked as the 3630. I have the manuals for both the 2050 and 3630 but they both have the same sill screen diagram in them (see attached)
I can upload pics of the board if needed, however this thread:
https://www.eevblog.com/forum/repair/smps-bench-supply-keeps-on-popping-output-rectifiers/
is for the same supply and has good images and I think has some useful comments too

Many thanks

 

This is not your psu , yours is a switchmode type, using a TL494 chip.
Measure the voltage at pins 14/7 to see if it's working.


Can you post any pictures of the pcb?

Thanks again, I forgot about your comment on the pinout voltages, currently the supply blows the fuse when plugged in and I have yet to try and isolate the mainboard from the outputs.
thanks

 

https://www.eevblog.com/forum/repair/smps-bench-supply-keeps-on-popping-output-rectifiers/
is for the same supply and has good images and I think has some useful comments too

You should be able to check the diodes in-circuit; as long as they don't have anything in parallel that would affect readings.