Products > Test Equipment
Power supply ripe for the picking
<< < (7/9) > >>
Antuan:
Picked up this model —HANMATEK HM310T— from Amazon. Lots of interesting features there for me there, specially the memory for predefined outputs.

Sadly the timer/counter, which starts counting in seconds when you switch on the output, runs faster than it should, and I'm not sure why. See a video here: https://imgur.com/a/hzxpSm1.

Returned it to Amazon and received a different unit: exactly same behavior. What's going on here? I may try to receive one again, but, should I?
geostep:
How many Hertz is the line frequency in Spain?  If it's 60 Hz and the PSU is somehow programmed to expect 50Hz then the clock would run fast.

If that's not it perhaps the PSU's were built with the wrong frequency of clock crystal?

- George
Antuan:
Hi George, 

Thanks for the response. Here we have 230V 50Hz. The interesting thing is that this PSU has an option to switch from 60Hz to 50Hz, and assuming that this clock issue was related to the frequency I did try setting it both to 60hz and 50hz. But it didn't have any effect, the clock was running faster in any setting.

I had no problem returning this unit to Amazon, but I liked the model and wanted a good one. So I wrote to the responsible of Hanmatek at Amazon.es: he asked me to write them to cs_es@hanmatek.cn with the details, but they didn't reply.

I'm tempted to give it another try with a third unit, I like the clock feature —if it actually works—.
Antuan:
Finally received a new unit of this model. I can confirm that the clock runs faster than usual with both settings: 50Hz and 60Hz. Also, both Spain and China, where this PSU is manufactured, have same frequency, 50Hz. As I tested now three units of this model I assume the whole series is defective.
tangodown281:
The HM310 I ordered from Amazon on Oct. 7, 2021 does not have this issue. After seeing this post, I tested it using Win 10 stopwatch and smart phone timer apps (my Omega Seamaster was in the shop). In both cases, there was no discernible clock difference between the PS and the apps after 5 mins. My unit was not under load and was set to 60hz in USA. I can say that after I received my order, these units disappeared for some time - a couple of months or so - so it's very possible the next production run(s) had this issue. I have had mine apart and the build quality is very good overall (soldering is much better than pics in this thread). I even tested the software that comes with it; very basic app and a little quirky, but interesting and potentially useful functionality. With moderate but consistent use, I've had no issues with the unit so far. As for the clock issue, since mine is good, I doubt it's a design flaw (PCB layout issue causing EMI). I don't remember an Xtal and I don't see an obvious one on any of peepsalot's pics - I would be surprised if they spent any extra time or money on this, so I would expect it to be pulled from an existing MCU with an internal clock, or a controller using the AC sinewave via a few external components. FYI, compared to my unit, your clock is about 12 seconds fast per minute from your video (hmmm, the math) - unless we want to get into your cameras shutter/aperture, file compression, my i7 CPU clock, ambient environmentals, coreolis effect and a hundred other factors  :-//

If it were me, and I needed the clock, I would do what comes natural... take it apart and see if I could track it down: an xtal or a lonesome ZD might get you in the ballpark.

HTH, assuming you still have the unit.   
Navigation
Message Index
Next page
Previous page
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod