Mastech HY1803D DC Bench PS.

[LtKernelPanic]

Edit: Since this thread got bumped I thought I'd add an update. The PSU is fine and I've used it without issue many times since. The problem was something I caused by not limiting the voltage to the max safe voltage for the diode. I'll leave the original post as a lesson in what not to do for anyone who my read this in the future.

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To say I'm a bit upset with this product is a bit of an understatement right now.

I purchased it earlier this week from Amazon since having a bench supply around would mean not having to rig up an LM317 driver and power supply every time I want to test a diode. It arrived Wednesday and I finally had time to try it out tonight. For constant current mode according to the directions you set the voltage knob to max, the current knob to minimum and power it up. Then you attach your load and adjust the current to your desired setting. I set everything up and it seemed to work great. The diode looked nice at 220ma (about half what I planned on setting the driver at) but I was starting to get reflections off the wall and decided it's be a good idea to get my glasses before continuing. I powered it down and went to get my glasses. When I came back I reset everything as before so I can monitor it from 0ma up to the 475 I planned on running it at but this time it goes up to 2ma I hear a relay click and the voltages shoots up to 18.5v @ 0A. WTF. A quick check shows everything was set correctly so I try again. Same thing. At this point smoke starts to shoot out my ears because I realized that even at 2ma the diode was toast. A quick check with my LM317 test driver (which powered it fine earlier tonight) confirmed it so now I have a dead $52 diode and a bench supply I can no longer trust. I don't want to know how much I'm going to have to pay to ship the damned thing to amazon.

So now that I've done my ranting does anyone have this supply? I'm trying to figure out if it's screwed up or if there was a ID-10-T error involved somewhere before I send this ting back next week. At this point I'm heavily leaning towards the unit itself being screwed up. I guess I can extract the red diode from the sled and use it as a guinea pig and see if it's the supply or user error since it's not a standard can and is more or less useless for hobbyist use. What sucks is I know DTR uses the 15v, 5A version made by the same company and he doesn't seen to have any issues.

Times like this make me want to take up drinking.

 

[Garoq]

I have this power supply and have used it in the exact same manner with no problems. Maybe DTR can chime in with his experience. What voltage were you reading on the display at 220mA?

 

[Leodahsan]

I have a friend that uses a similar bench PSU.. and he says that he needs to short the output before adjusting CC modes.. I may be wrong just my 0.02 cents..

 

[Bluefan]

Bench psu's are constant voltage sources with current limiting, the filter capacitors can toast diodes easily. Use a proper driver or a bigass resistor (which would turn it into sort of a current source).

 

[jib77]

These PSUs should current limit at any voltage, not just max. What I do is set the max voltage for the diode that Im testing for, turn it off, hook up a dummy load, turn it on, dial back the amps just below the lasing threshold, turn it off, take out dummy load & short the output, hook up diode, turn it on.
Also, measure your output(under load) with a DMM, I found mine is off ... for example, when the voltage setting shows 3.0V the output is really 3.3V.

 

[DTR]

I have had the 3A model you have and now I have the 5A. Never had any complaints with them or unexpected losses. It is a cheap power supply that works great for what you pay for it. If you are hooking it up to a diode you need to set the voltage to the top of the range. So if you are attempting to direct drive a 445 I would set it to like 4.8-5V to start and turn the current all the way to the bottom. Then hook up the diode up, turn on the power supply and slowly turn the current up. If you set the Voltage to max you have the ability to accidentally turn it up way too high and kill the diode. If you are testing a driver you want to simulate a battery you will turn the current to 4.2V or 8.4V or whatever power source that you will be using and turn the current all the way up and the driver will draw whatever it needs.

 

[LtKernelPanic]

Sorry to post and run the other night. I was in a foul mood after that and following my own advice I decided to step away for a day or so. I also had real life get n he way for a bit too. How dare it!

DTR-

You're right about the current limiting at any voltage setting. I should have done that which I realized later. It should have been set to 4.5v or so. I did test it in constant voltage mode by setting it to 12v and letting it draw what amperage it needed to run my HeNe's PSU. That seemed to work ok. I need to find a couple of the diodes I extracted from my old DVD burners to test it in constant current mode some more. I'm still wondering why I heard a relay or something click like that when I started to turn the current up.

Oh well another addition goes into my diode coffin.

 

[daguin]

I have the HY-1803DL and the HY3006D. I use them both, with laser diodes, without any problems.

Peace,
dave

 

[Wolfman29]

I used to experience that, I think. That happens whenever there is a short. Is it possible that there was a tiny short, and then it unshorted (movement of the hand, or something)? Because after the short is over, I would think it would need time to compensate and drop the voltage back down, even if it only takes a microsecond. That much over current (3A) is enough to kill any diode here in that time.

EDIT: Aww, crap, necropost! Was doing some internetz searching to get some more information on mine, and saw this.

 

[LarryDFW]

LtKernelPanic;

A year or so ago I tested over 30 Red LD's for output with a similar supply.

The testing procedure that caused the least failures was:

Set the maximum voltage to slightly above the maximum needed (3.5VDC for most Reds).

Connect the LD, then slowly ramp up the current by while operating the the LD.

To shut down, ramp down the current to close to zero.

Do NOT connect or disconnect the LD while at high currents.

Red's are the most sensitive to failures.

I use a better designed Extech power supply now, but still follow the same procedure.

LarryDFW

 

[LtKernelPanic]

I should have updated this post awhile back. It was user error. I don't recall exactly what I did but after going back over it I realized I had made a fatal (to the diode) mistake. I've used it many times to test things fine since then although I haven't tried testing a diode directly since.

 

[hakzaw1]

Its all good advice so being a necropost is no big sin- many are powereing up diodes these days for the first time so....its deff. worth a +1 to me.
(when I can)

hak

 

[Wolfman29]

Well that's good Kernal. Not for the diode, but for experience. Because I love my HY1803D!

 

[Cyparagon]

For constant current mode according to the directions you set the voltage knob to max, the current knob to minimum and power it up. Then you attach your load and adjust the current to your desired setting.

Even if the current is set at zero, the voltage on the filter cap can creep up enough to kill a diode if you have the voltage set to max. I always have the voltage at zero when making connections.

I do have the same model, and use it on laser diodes all the time.

 

[LtKernelPanic]

That's probably what happened to me since it was a quick spike. I just wished it happened to say a $7 PHR diode instead of a $52 12x diode (which I still need to replace).

If you don't mind me asking how do you test your diodes? I assume you'd attach the load, turn up the voltage to whatever the diode uses (say 4.5v for my fried 12x) then turn up the current? Like I said I've used mine many times for powering drivers and other thing since but I've been a bit gun shy of testing diodes.

 

[DTR]

Here is how I test a 445 diode.:beer: