Well, I am putting Greg Balls GB150 together and for some reason thought it a good idea to try one of those Chinese smps.
I got one 300W with +48 0 -48 secondaries and the regular L-PE-N primary.
I added a 2A slow blow and it keeps blowing at startup. Even with the amplifier disconnected.
Am I missing something?
I got one 300W with +48 0 -48 secondaries and the regular L-PE-N primary.
I added a 2A slow blow and it keeps blowing at startup. Even with the amplifier disconnected.
Am I missing something?
Hi. Check with ohmmeter if any of ac input pins ,including pe, have relation to output pins. Sometimes ac pe is connected to output gnd ,or output negative, if output is single .
Where is the fuse connected? Draw a schematic.
Are you grounding the positive output of a negatively grounded supply?
Are you grounding the positive output of a negatively grounded supply?
If there is a fuse in the AC inlet (which is sort of looks like) then it's possible that it can't handle the inrush current from the SMPS (which seems likely if it blows even with the load disconnected). Is it a fast-blow or slow-blow fuse (= is it marked F or T)?
Nisbeth.
It is as you say, fuse holder is in the inlet and it is a 2A slow blow.
Rayma.
As above, fuse holder in inlet in series with the live wire.
Primary side PE is grounded in the chassi and connected to the inlets earth lug/pin.
The secondary side "0" is connected to star ground.
But even if I completely disconnect all wires from the output side of the smps the fuse still blow.
Ximikas.
No relations between any pins on primary and secondary side. Ground/earth included.
It is as you say, fuse holder is in the inlet and it is a 2A slow blow.
Rayma.
As above, fuse holder in inlet in series with the live wire.
Primary side PE is grounded in the chassi and connected to the inlets earth lug/pin.
The secondary side "0" is connected to star ground.
But even if I completely disconnect all wires from the output side of the smps the fuse still blow.
Ximikas.
No relations between any pins on primary and secondary side. Ground/earth included.
Measure AC nput resistance in diode mode. You should have readings like 0,500 starting and increasing till "1" display. If reading is constant, mosfet or one of diode bridge diodes failed. If reading increases, try big incandescent lamp in series, or powerful heater. Especially good in place of blown fuse. If smps will function through lamp or heater, fuse needs to be larger, or ptc resistor not included.
Ximikas
I had a lightbulb setup and with it, the fuse doesn't blow.
I get around 10V at startup between the positive output and 0 but it decreases to 0 in a few seconds.
This is without load on the outputs.
I had a lightbulb setup and with it, the fuse doesn't blow.
I get around 10V at startup between the positive output and 0 but it decreases to 0 in a few seconds.
This is without load on the outputs.
After capacitors stops charging, lamp should be not lighting and practically all ac voltage pass ac input of smps. Output voltages should be normal then without load. Maybe faulty smps ? Can you try a more powerful lamp, or few in parralel?
Possibly a diode bridge has shorted diode, wrong voltage varistor is installed, or voltage doubler enabled for 120v version, but you are trying to power it from 230v.
I was told by Nelson Pass that you cannot use a DBT (Dim Bulb Tester) with SMPSs. I was doing this when testing an ACA I built with SMPS power supplies and the bulb stayed bright.
You can't use led bulbs, but you can use any enough powerfull incandescent lamp in series with mains, at least for testing. For everyday use this is not solution offcourse, lamp will heat up and cause power loss, decrease smps efficiency. I'm using ac socket in place of fuse, while repairing or experimenting with smps, and connect there a 100w or 300w bulb, depending on situation, and have not issues of that.
That depends very much on the SMPS concerned. Some are fine with a bulb provided any load on the output is not to high while others can latch and draw lots of current lighting the bulb.