MCH-K305D cheap switching lab power supply - Page 1
Forum section: electronics / testgear

author: Imi3est
author_rank: Newbie
timestamp: November 30, 2014, 09:00:45 pm
content: Hi!I just want to show a cheap switcing lab power supply: "MCH-K305D". I bought it for hobby purposes, so I didn't want to spend too much. It was 70$ with shipping.I haven't tested it totally. I will check it later with oscilloscope. I checked it with some leds an resistors. I also havent tested it at high load. Max load was 20-30W which I tested. It was interesting that the fan haven't started. I checked the three heat sinks on transistors which was quite cool so I hope this is why the fan haven't started. I think it is not too bad for that price. At low currents the current limiting is not perfect. If I start to decrease the current limit, it sometimes goes down to 0. If I start to increase it, it jumps up to 50-100mA. Voltage adjustment is quite good, its precision is around 0,05V.I think for hobby purposes it is not a bad power supply.I wrote this little "review" because I haven't found any info before I bought it. (sorry for my bad english)I would like to see others opinions about this item.advantages: (based on my limited electronic knowledge)+ cheap+ good voltage precision+ silent (at less than 30W - or bad fan ?)+ switching supply - so I think is is efficentdisadvantages- not too good current limiting- not a known reliable brand

author: Macbeth
author_rank: Super Contributor
timestamp: November 30, 2014, 10:01:58 pm
content: It states 30V/5A which would suggest a max load of 150W, so at 30W I think you are being over cautious!I have a similar SMPS that I bought years ago from a Maplin storeN93CX (20V/5A 100W)when they dropped it from £89.99 to £49.99 during a sale. Though my first supply gave up the magic smoke (yet still worked with an annoying buzzing), I swapped it no problem and it has been fine ever since. It's worth it as a light portable supply with CV/CC.I believe it is also sold as Tenma and Manson.It is nothing compared to my linear Rigol DP832 and HP 6632B though.

author: tautech
author_rank: Super Contributor
timestamp: November 30, 2014, 10:44:11 pm
content: Quote from: Imi3est on November 30, 2014, 09:00:45 pm@Imi3estWelcome to the forum.Be assured they are a good little PSU although as a SMPS they do have some ripple.The fan controller is "smart" and even at max load it still cycles the fan, this demonstrates the cooling design is sound.(15-25 C ambient)Yes the only 5 turn pots could have been 10 turners but the resolution is adequate for a cheap PSU.We have given them a hiding with no failures to date @ ~ 2 years.BTW. No voltage overshoot on power up negates the need for a switched output with these PSU's.

author: bluey
author_rank: Regular Contributor
timestamp: November 11, 2017, 09:10:19 pm
content: Company has been around for 20years.http://www.china-mch.com/index.php?l=enDesign of this power supply apparently new/updated.

author: tops4u
author_rank: Newbie
timestamp: December 30, 2024, 03:41:04 pm
content: I know this is an older topic, just wanted to share a few remarks as I have the same device.Mine shows quiet a bit of voltage drift after switching it on:It does not reach 150W as advertised. It goes all the way up to 32V but never exceeds about 4.5A without going into Current Limit.Today I powered a small DC Buck Converter with it and I noticed a bit an unexpected behavior with the current limiter, as i only kicked in at more than 170mA and went then down to 110mA. This pattern was repeatable at various current limits.