Tenma DC Power Supply 72-10505 dual 30V 3A, the most lame design  - Page 1
Forum section: electronics / projects

author: oz2cpu
author_rank: Frequent Contributor
timestamp: April 15, 2025, 07:58:02 am
content: I have been playing with this terrible psu for a few daysTenma DC Power Supply 72-10505 dual 30V 3Ait is crasy how lame it is made, its user interface is plain bad,design and manufacture quality is below zero,i found a few funny things the DAC is made using a whole lot of passive parts,instead of just using an DAC-ICi made a little video showing all the details i foundhttps://youtu.be/4OlTU5qiW64by the way : you can still get this one from brand new.. but please just dont..

author: Kleinstein
author_rank: Super Contributor
timestamp: April 15, 2025, 08:15:59 am
content: The design does not look that bad. It is just made for a low price.The R2R DACs are just the cheaper solution. Ready made DAC chips with some 12-16 bit resolution get a bit expensive. The supply should have 2 DACs per channel. For a lab supply the accuracy expecially DNL error of the DAC is not that important.The bare wire shunt for the current measurement / reulation actually looks relatively good, though it still depends on the alloy quality (not all manganin wires are equally good).The heat sinks are relatively small. So the fan would have to run even with only moderate loads.For the user interface one may just get used to it - which may be a bit tricky with a broken supply.

author: ivo
author_rank: Regular Contributor
timestamp: April 15, 2025, 04:32:47 pm
content: A LOT of people have different models of these. Yes, including me. Korad is another OEM name for them. For instance Curious Marc channel, you can see it in many of their videos. I think I remember seeing them a tonne of them in LinusTechTips' commercial PSU test rack that they bought. They're everywhere.If you refuse to buy a terrible cheapo chinese switching supply with dual and fine knobs and who knows what switching noise at the output, this has been the next step up for hobbiests for a long time. And I think in a lot of industrial. Actual linear supply, decent response, interface is basic but workable with channels. You can get them USB programmable as well.Higher end supplies from other brands would find many ways to outshine them, but probably at 2x-3x the cost. This has been true the last few years anyway. It gets the barebones right: decent, very quiet ripple, linear, current limited PSU. And made down to cost to achieve that.It looks like most of your difficulty with the interface is that the things were half broken to begin with and not acting how they should normally. Of course it will be impossible to logically figure out how they work in this case.

author: tatel
author_rank: Frequent Contributor
timestamp: April 15, 2025, 04:52:26 pm
content: If you get just the left half it's almost exactly the same than my Korad KA3005P, 30V 5A cheap linear power supply. It has served me well for about 4-5 years now.I know, not the best power supply in the world, but good enough for me so far. That's the reason I'm not in a hurry to get another power supply.YMMV

author: bingo600
author_rank: Super Contributor
timestamp: April 15, 2025, 06:20:14 pm
content: For linear PSU'sI tend to pick my Korad KA3005PS a lot more than my HP 6632B's.I don't have to wear ear protectionWell when i get my HP E3610A recapped , then i might grab that one.If volt/amps matches the HP.Maybe the new PS design is diffrent from the Tenma, but i think my KA3005PS is worth the modest 100€ i paid..

author: oz2cpu
author_rank: Frequent Contributor
timestamp: April 16, 2025, 08:34:42 am
content: i should maybe not complain, i got it for free, from the local e-waste like so much other fun to play with equipment,most come defective, most end up working when i am done playing with it.

author: wraper
author_rank: Unknown
timestamp: April 16, 2025, 08:48:50 am
content: It's a rebranded Korad.