Vantek DPS 3305P 32V/5A/160W Programmable DC Power Supply

[rowant]

I grabbed one of these Vantek PSU's for $135 off ebay delivered, however, I made a stupid mistake and managed to break my ICD3 programmer and the board I was attempting to program..

I'm guessing it was because I forgot to link negative to ground, and a path was created from negative (I hadn't even connected positive yet!), through the programmer cable, through the USB cable through earth and back - however it was a massive amount of current, enough to melt the programming port and lead, as well as pop a PIC32, DP83848 phy transceiver and 34V SMPS IC, with just negative connected..

After having a look at the difference between negative and earth/gnd, I noticed that it sometimes creates a 30-50v DC offset from negative to gnd, and if I attempt to short the two I get a massive spark, is that normal?? Is it safe to connect negative to gnd permanently like on other PSU's if I won't want it floating? I'm worried it'll blow itself up lol

Also, on this Vantek unit it doesn't do the voltage overshoot when powering up, nor does it supply excessive current when shorted when the output is turned off.

[rowant]

Hrm ok, I put a meter on 10A current test mode and connected it from negative to gnd/earth, technically it should just make the psu not floating right? Instead, when I turned it (for the brief 500ms) the meter went into over range and I heard like a intense heating up sound from inside the PSU (like plastic cracking), so I immediately turned it off.

This is not normal!

Edit:

Ok, so in addition to that issue I also found that when using the wheel to adjust the voltage on the fly with the output enabled you'll get random sudden spikes 15+VDC above the setting very briefly.. I can't connect my scope to see this because if I did that my scope's ground cable will MELT because of the above issues mentioned, so its completely useless if I want to use a scope on anything powered by this power supply. Here's a short video I took of the issue with it connected to my multimeter instead:
https://www.youtube.com/embed/WeN_tQPRwvk

[megajocke]

Is the negative output negative in relation to the ground terminal? If that is the case I'd suspect that there is a short between the collector (tab/back plate) of the pass transistors to chassis of the instrument. Maybe they aren't properly mounted to their heatsink or the insulating pads could be damaged.

[rowant]

Yeah both output terminals are negative in relation to the ground terminal, and the voltage difference does actually change with the selected voltage on the knob from ~20v to 50v.

I think you're right about it being a short somewhere, if I tap the rear of the power supply or move it about the voltage difference jumps about. I've taken the cover off and tried to have quick look but didn't see anything obvious in the time I looked, I'll take a closer look later in the week.

This video shows the DC voltage between Ground and the Negative terminal and it changing when adjusting the output voltage (even with the output off):

[metalphreak]

Definitely something up with yours. I get a reading in the millivolts range between negative and ground which is essentially all noise. Shorting out negative to ground and there is no current. Check the transistor insulation because sometimes if its not installed correctly it can pierce the insulating pad and its not obvious (and it would be touching the grounded heatsink).

Are you running yours on 110v or 220v?

[poorchava]

Is that only my impression or does it look SURPRISINGLY similar to the Korad PSU that has blown up during Dave's tests?

[T4P]

Is that only my impression or does it look SURPRISINGLY similar to the Korad PSU that has blown up during Dave's tests?

It's basically the same model ...

[metalphreak]

Yeah it's similar but not the same. Most of the power supplies out of China use the same generic parts. The chassis, front panel, control boards, and so on. Seems to be a bit of a mixed bag in terms of exactly what internals you will get, what revision board, firmware etc. I seem to have been incredibly lucky with all of my Chinese gear purchases although you really only ever see people posting if they have issues (as is the case with any product). Then again, I am more than happy to spend a bit of time fixing or improving some of the small issues, considering the rather good prices.

[rowant]

220VAC

I've pulled it all apart, the back of the two transistors there was no insulating pad, just the metal on the rear onto the heatsink direct (with some thermal paste). I've insulated the entire heatsink from the case now though and it seems better. The voltage still jumps up high when adjusting the voltage with the output enabled though, so I have to disable the output, change the voltage, then re-enable which is pretty annoying..

[carter_383]

Hi,

Sorry for reviving such an old thread.

Is anyone able to upload a copy of the software provided on the CD, I recently got one of these on eBay and i cant find anything online manuals or software.
Failing that i assume this is a clone of another PSU does anyone know what the original is?

Many Thanks
Charles