WEP 3010D Power Supply Short

[Easky15]

Hi, I have here a WEP 3010D PSU and I was recently using it to charge some 18650 LiIon cells, I had made a battery pack and was about to charge it, I had voltage set at 24v and current was set at about 100 - 300mA then i was going to increase when it was all connected but as i clipped the positive wire on to the pack i seen a spark and now it wont put out any voltage, also when i use multimeter on continuity setting i see a dead short between the positive and negative terminals on the PSU, Here is a video showing the fault,

http://tinypic.com/r/68g6er/8

[redwire]

Re: WEP 3010D Power Supply Short

With the power supply off, measure ohms and diode-test between the output binding posts. Most bench power supplies have a reverse-diode on the output. The diode gets overloaded and shorts when (reverse) connected to a battery pack. I'll dig for the schematic when I get home.

[Easky15]

Re: WEP 3010D Power Supply Short

Now that might be a possibility, I may have connected it backwards, I haven't got my fluke 87 here at the minute so just have a crappy multimeter to go by and it's saying 1.2 ohms? I'll try find my good meter tomorrow and retest...

[redwire]

Re: WEP 3010D Power Supply Short

Here is a schematic for a generic Chinese bench power supply 0-30V at 3A. They are all very similar and can be difficult to troubleshoot.

Diode D4 (1N5401) is probably shorted and is stashed behind the output binding posts or sometimes located on the main board. If you can't find it, hook up another battery and look for the smoke. That's how I found it...

There are a few other failures these power supplies have. The pass transistor Q1 shorts or the op-amp U1 fails.
If the power supply is off and you connect a battery to the output, current will backfeed in and cause damage. You have add a diode across Q1 C-E to protect it.

[Easky15]

Re: WEP 3010D Power Supply Short

Only thing i see behind the binding posts is a 50v 470uf cap and a 6800uf 50v one, Here are a few more pics,

https://lh6.googleusercontent.com/-r...219_163631.jpg

https://lh4.googleusercontent.com/-q...219_163607.jpg

https://lh3.googleusercontent.com/-f...219_164420.jpg

So what voltage of battery should i use?

[Easky15]

Re: WEP 3010D Power Supply Short

Just hooked a car battery up and forgot to check polarity first then the 50v 470uf cap just exploded, Now I think i properly wrecked it,

[Easky15]

Re: WEP 3010D Power Supply Short

Can you suggest a good replacement thats not too expensive?? Sick buyin cheap crap and it only lasting a short time, ;-)

[stj]

Re: WEP 3010D Power Supply Short

lol
i think connecting several hundred amps of battery to it the wrong way around will blow even the best psu!

[Easky15]

Re: WEP 3010D Power Supply Short

I blew something but its now working better than it was, I removed that blown cap and now it outputs voltage fine and display is still accurate as i tested output with multimeter but the current display seems to be a bit messed up,

Homemade firecracker..

http://tinypic.com/r/9k79g7/8

;-)

[redwire]

Re: WEP 3010D Power Supply Short

Hmmm me bad. Instructions unclear. Car battery is a bit BIG to smoke out a diode... then you added capacitor smoke?!
In your original video, the ammeter seemed to be reading high, is this right.
A trace could have melted and messed up the meter but I don't see the reverse-protection diode in your pics. It could be on the small PCB where the wires solder onto the backside of the binding posts.

I would fix it, add the two 1N5401 protection diodes, and quit smoking.

[Easky15]

Re: WEP 3010D Power Supply Short

I thought the car battery was a bit big myself but it was all i had lyin around, I had a 12v 10Ah LiIon pack i was going to use but it was dead and had nothing to charge it as psu broke, In the original video the meter was showing max current being output and 0 voltage due to a short somewhere, car battery backwards kind of fixed it, I've replaced the 50v cap behind the bind posts and ordered those diodes, I've it hooked up now charging the 12v LiIon pack and using the multimeter to measure the current,