Electronics > Repair
Korad KA3005P power supply faulty/repair
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pomonabill221:
IF the supply is floating (which it should be), you should be able to ground (connect to earth) either the positive or negative output.
This is a common way to obtain a negative voltage referenced to ground (earth).
I know that sometimes ground and negative are interchanged, but in this case I am referring to earth as ground.

Great that your supply is working!
Just remember that it does have it's inherent problems (like spiking on power on, a slight overshoot when the output is turned on (could damage what you have connected)).
If you have a scope, take a look at the output to verify these symptoms... and remember it IS a cheapy chinese product, but I like it and I could afford it.
tony3d:
I have been using mine for months now with no issues at all. I wouldn't leave it unattended pushing 4 amps, but anything under an amp or so I feel very confident with.
pomonabill221:
I agree with not leaving it unattended pushing high current, but it's over temp seems to work pretty good (I found out), and I would feel safe at about 3 amps max., just watch the temps and feel the fan's output air temp.
Still.... it's not a bad idea to be around while it is powering something, just to be sure!
AllanMN:

--- Quote from: pomonabill221 on January 28, 2014, 09:11:16 pm ---Here are some pics of the bridge (notice the slight space on the lead side), the xsistors and bridge (notice how the goop doesn't look like it was making contact on the bridge), and the contact area on the heatsink (only partial contact on the bridge).

--- End quote ---

Mine had a bolt tightened through the bridge and it was tight. Like my crushed wire, assembly has many errors without QC to catch it.

commongrounder:
After reading about AllanMNs experience with a trapped wire, I figured I had better take a look inside mine to see how it faired the assembly process.  Mine did pretty well.  I found a couple of loose screws on the power transformer (mine is the dual supply, and the xformer is huge and heavy).  I also found the regulator board for the fixed 5-volt supply had a screw missing, which I replaced.  Here is something interesting.  I can see the area where the I/O connections are made, but mine is not a USB/RS232 version.  However, the circuit board is sitting right there, half populated.  Even the opto-isolators are there.  I wonder, if there were a way to determine what chips are used, whether my unit could be converted to have I/O capabilities.  If someone were willing to post a photo of that board that has the I/O connectors and related circuitry, I might be able to create a parts list for the conversion (assuming the parts have visible labels).   I could also post a photo of my partially loaded board for comparison.
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