Tekpower TP3005T Variable Linear DC Power Supply - Page 1
Forum section: electronics / testgear

author: MarkF
author_rank: Super Contributor
timestamp: July 17, 2015, 03:55:59 am
content: Looking for a sub $100 power supply. Does anyone have thisTekpower TP3005Tor seen a review?

author: Electro Fan
author_rank: Super Contributor
timestamp: July 17, 2015, 05:08:04 am
content: The TP3005T looks pretty good. FWIW, I have a Tekpower TP1503C (15 Volts, 3Amps, analog meters, CC and CV) that sells for about half the price of the TP3005T. I like it and use it occasionally but I also have a Korad KA3005P which I like and use much more often. The Korad will cost somewhat more than the TP3005T but for me it's worth it due to a few features. 1) In addition to a rotary knob for changing values it has a couple arrow keys that I think might speed up the setting process over how the TP3005T works (this is just a guess since I haven't used the TP3005T. 2) It has a DC output on/off button (to me, this is a very useful feature, others might not care.) 3) The memory buttons are also useful. 4) It has a USB port for PC control. Korad makes a similar model KA3005D that doesn't have the USB port.http://www.amazon.com/KORAD-KA3005D-Precision-Adjustable-Regulated/dp/B0084JFWNY/ref=sr_1_3?ie=UTF8&qid=1437109319&sr=8-3&keywords=koradBut for about $7 more the USB port on the KA3005P is probably an ok investment. Based on how the Tekpower TP1503C operates I think the TP3005T might be a fine unit if you can't justify the extra $ for one of the 3005 Korads.

author: dmmt40
author_rank: Regular Contributor
timestamp: July 18, 2015, 06:15:39 pm
content: I've actually purchased this supply just a couple of days ago, but won't be receiving it until next week. I'm going to take a look inside to check quality, safety, etc if you want I can post some pictures.I think it came out just 1 or 2 months ago that's why there's little info about it.

author: Electro Fan
author_rank: Super Contributor
timestamp: July 18, 2015, 06:23:58 pm
content: Quote from: dmmt40 on July 18, 2015, 06:15:39 pmdmmt40, Welcome to the EEVblog forum! Please let us know your impressions of the TP3005T. EF

author: dadler
author_rank: Unknown
timestamp: July 18, 2015, 10:08:06 pm
content: Is this the same supply rebranded?http://www.circuitspecialists.com/csi3005t.html

author: MarkF
author_rank: Super Contributor
timestamp: July 19, 2015, 04:35:59 am
content: Quote from: dmmt40 on July 18, 2015, 06:15:39 pmI don't have an immediate need, so pictures would be great. If you do any testing, I would be interested if there's any large overshoot when the power is turned on and what the ripple and noise is like. Also, how it is to operate.Thanks.

author: Electro Fan
author_rank: Super Contributor
timestamp: July 19, 2015, 09:08:03 am
content: This is from a Tekpower TP1503C Power Supply.Different model than the one you are interested but it's a less expensive version (15V, 3A, analog meters).Images show turn on and turn off from main AC switch. Also an image showing the Voltage set to about 2-3 mVolts (my Fluke 179 fluctuated between 2-3 mV while trying to very delicately set the power supply voltage knob).Not too bad for a $39.99 Power Supply.

author: tautech
author_rank: Super Contributor
timestamp: July 19, 2015, 09:25:13 am
content: Quote from: Electro Fan on July 19, 2015, 09:08:03 amAnd one while under a moderate load, say 1A @ 12V AND AC coupling?

author: Electro Fan
author_rank: Super Contributor
timestamp: July 19, 2015, 09:35:16 am
content: Quote from: tautech on July 19, 2015, 09:25:13 amI'll give a try (it's getting late here).One other note, I think my scope reads about 4-8% high on voltage when measuring in the 0-10 Volts range. I've come to think that scopes in general don't measure voltage as well as DMMs but maybe it's just my gear or technique.

author: tautech
author_rank: Super Contributor
timestamp: July 19, 2015, 09:44:47 am
content: Quote from: Electro Fan on July 19, 2015, 09:35:16 amWithout a load on the supply, quite likely.Other than high end scopes are rarely very accurate, for AC and DC within capability of your DMM, trust it.

author: Electro Fan
author_rank: Super Contributor
timestamp: July 19, 2015, 10:12:01 am
content: Quote from: tautech on July 19, 2015, 09:44:47 amDo you want the channel AC coupled, or the trigger AC coupled, or both AC coupled?

author: tautech
author_rank: Super Contributor
timestamp: July 19, 2015, 10:36:36 am
content: Channel AC coupled only.

author: Electro Fan
author_rank: Super Contributor
timestamp: July 19, 2015, 11:12:12 am
content: Quote from: tautech on July 19, 2015, 10:36:36 amBest I could round up (so as to keep my resistor from getting too hot) was a 10 Ohm, 10 Watt, 10% resistor - so I set the Power Supply for 5 Volts and drew about 0.5 Amp as confirmed by a couple multimeters.Channel AC coupled only On and Off, followed by other variants for your viewing delight.

author: Electro Fan
author_rank: Super Contributor
timestamp: July 19, 2015, 05:03:46 pm
content: Quote from: tautech on July 19, 2015, 10:36:36 amtautech,I've previously just looked at the DC coupled waveforms (looking for overshoot and noise). What is your diagnosis of the AC channel coupled images? Are those what you expected or were you looking for something else? Thx, EF

author: dmmt40
author_rank: Regular Contributor
timestamp: July 19, 2015, 05:50:11 pm
content: Quote from: dadler on July 18, 2015, 10:08:06 pmYep, I think so.

author: dmmt40
author_rank: Regular Contributor
timestamp: July 19, 2015, 06:00:55 pm
content: Quote from: MarkF on July 19, 2015, 04:35:59 amNo problem I will do some tests on it.Electro FanThose are some good pictures, it seems like a good PSU for the price, the only thing missing though (and I think what tautech was suggesting) is to look at the ripple under load with AC coupling, should be easy now that you have everything setup.

author: tautech
author_rank: Super Contributor
timestamp: July 19, 2015, 08:45:32 pm
content: Quote from: Electro Fan on July 19, 2015, 05:03:46 pmI was hoping for a shot of ripple under a moderate load. Could be any load, I suggested ~1A and 12V thinking you might have maybe an auto light bulb or similar.AC coupling is to exclude the DC and channel attenuator needs to be set right down low in the mV ranges. With a Linear supply, ripple will most likely be at mains frequency, so the Timebase should be set for that but have a look for any HF stuff too.Reasonable specs will be under 5mV ripple, good under 2mV.Quote from: dmmt40 on July 19, 2015, 06:00:55 pmExactly.

author: Electro Fan
author_rank: Super Contributor
timestamp: July 19, 2015, 09:33:51 pm
content: Not sure if this is what you guys are looking for. I left the 10 Ohm, 10 Watt resistor in place with the PS set to 5 Volts DC output. This is drawing 0.5 Amps. I set the scope for 50 mV and 50 ms for one and 50 mV and 10ms for the other. ... Added one more at 50 mV and 5 ms. The long spikes might correspond to the 60 Hz AC cycle? Let me know if you want me to try something different.

author: Electro Fan
author_rank: Super Contributor
timestamp: July 19, 2015, 09:53:55 pm
content: Here is another at 20 mV and 1 us. What is interesting about this is that the Power Supply was OFF; but the two DMMs were still connected and turned on. I'm going to run another to see what happens when I remove the DMMs.

author: tautech
author_rank: Super Contributor
timestamp: July 19, 2015, 09:57:39 pm
content: Quote from: Electro Fan on July 19, 2015, 09:33:51 pmWe're looking for PSU ripple. This is how PSU quality/design is judged.Yep, that sort of stuff, but your trigger level is above the waveform and trigger set tor +&- triggering not just rising. Set probe and channel input to 1:1.It's also likely some of the garbage is from your surrounds/workplace.Turn on some averaging to clean things up a little.Thanks for your trouble.Quote from: Electro Fan on July 19, 2015, 09:53:55 pmYea, it tricky trying to do stuff that others want to see, especially when in a hurry and you don't do that stuff frequently.

author: Electro Fan
author_rank: Super Contributor
timestamp: July 19, 2015, 10:01:57 pm
content: I'm happy to keep trying. Here is one with the DMM's completely out of the testbed.

author: tautech
author_rank: Super Contributor
timestamp: July 19, 2015, 10:07:44 pm
content: Quote from: Electro Fan on July 19, 2015, 10:01:57 pmDisconnect DMM, attach load to PSU, probe at PSU terminals.PSU ONAquire menu, set to averaging, let's say 64.Have a play around, there's no hurry.

author: Electro Fan
author_rank: Super Contributor
timestamp: July 19, 2015, 11:52:43 pm
content: Ok, learning something here. I have a noisy environment.All of the following is done with AC channel coupling.Turns out that about smallest increment I can discern with just the Rigol scope turned on is about 250-500 microVolts. That is, with nothing plugged in and the channel on the signal displayed on the screen with it's attendant noise is about 250-500 microVolts. When I plug in a Tektronix BNC cable (about 30" long) nothing changes on the scope signal - it is still approaching 500 microVolts. When I add a BNC to banana plug connector (so the banana plugs can plug into the Power Supply) the signal jumps to a range of 2.5 milliVolts to 5 milliVolts depending on the orientation of the cable with the connector (it seems to act as an antenna).When I plug the BNC cable from the scope through the BNC to banana plug connector into the Power Supply (with the Power Supply OFF and it's AC cord disconnected from the PS), the signal settles down to show about 2.5 milliVolts at it's "core" but the nose emanating from the top and bottom of the "core" of the signal takes the signal to about 7.5 milliVolts peak to peak. Plugging the AC cord into the wall and into the PS doesn't have any impact on the signal amplitude.When I turn the PS on to 5 Volts (with no load), the signal rises to 5 Volts and looks clean but when I zoom in by setting the scope to 5 mV it becomes apparent that the signal has a "core" component that is about 2.5 mV and the noise takes the overall signal to about 7.5 mV peak to peak - this is with no load.When I turn the PS off, attach the load to the PS, and attach the scope to the PS I get a signal of about 8.3 mV peak to peak. When I turn the PS on, I get the image below which shows what I refer to as the "core" of the signal being about a third of the overall signal which measures with the cursors as being about 9 mV peak to peak.How much of the 9 mV is due to the PS and how much is noise from cables, connectors, or all of the above acting as an antenna I don't know but after working my way through this I am thinking that some of it is noise from the environment. I have found that depending on how I orient cables and connectors and how I hold them can have a dramatic impact (10x?) on the noise level.So, my assessment so far is that the Tekpower TP1503C has relatively little overshoot on turn on and turn off (see the earlier images posted) and it might be about 3 mV for ripple. I can't say for sure given my adhoc technique and what I think is a noisy setup and/or environment.Over thoughts: I like having a PS with analog meters but I wouldn't want it to be my only PS. If I only had one PS there is no doubt it would be worth the extra $ to have digital readouts for Volts and Amps, but all in all if someone needs a PS for $40 the Tekpower TP1503C seems like a reasonable starter unit (but I'd still hold out for digital readouts if you can).

author: Electro Fan
author_rank: Super Contributor
timestamp: July 20, 2015, 12:59:04 am
content: Quote from: tautech on July 19, 2015, 10:07:44 pmI tried averaging at 64. Using averaging with Stop yields about the same results as reported above (about 9 mV peak to peak). Using averaging while in Run shows a peak to peak of about 2 mV - 4 mV depending on how you interpret the display (minus a few outlier spikes it's 2 mV, taking into consideration a few spikes across the display it's 4 mV).- Thanks for the guidance

author: tautech
author_rank: Super Contributor
timestamp: July 20, 2015, 02:30:50 am
content: That result is fine and a good indication that ripple is reasonably low.Averaging can be useful in noisy environments.You shoud be able to do screen captures without having to Stop the scope.Got a Print or Save button or similar?You might have to change settings to get it to print/save to USB.

author: dmmt40
author_rank: Regular Contributor
timestamp: July 29, 2015, 04:20:02 am
content: Hello, as promised here’s some pictures of the TP3005T, it's not a proper review but if someone has any questions I'm happy to answer.First a look inside, as you can see it uses a very well known design with the transformer in the middle, regulators at the back and control board at the front.The fan is directly behind the heatsink which seems like it will be adequate for the job.Mains filtering happens on the ON/OFF switch pcb, which is also covered with a small plastic sheet.If you look at the main board, you can see in the center a PIC 16F1887, top left shift registers for driving the display, local regulation on the right (with its own tap from the transformer) and the DAC below.In the last picture you can see someone had to trim the current sense resistor, also look at the burnt capacitor below obviously with a soldering iron while joining the wires around it.Anyway apart from that small issue the overall construction seems pretty good and safe, lots of heatshrink sleeving and proper connectors although there’s still a handful of wires soldered directly on to PCBs but it's not a deal breakerNext a few measurements...

author: dmmt40
author_rank: Regular Contributor
timestamp: July 29, 2015, 04:25:31 am
content: First voltage, when I measure with my 0.5% accuracy, 6600 counts DMM it stays within +-1 of the least significant digit across all ranges.For current my DMM has 1% accuracy and it always reads around 0.9% low of the nominal value, it could be the meter or the supply but it's always within 1%I’m sorry I couldn’t take ripple measurements my scope isn’t great, but I'm pretty sure it's under 6-7mV since that's the base noise of my scope and I couldn't see any difference.However, I did manage to do some overshoot tests.Picture #1, switching the supply on to 5V with no load#2, 5V with a 100ohm resistor#3, 10V with a 100ohm resistor#4, a solenoid around 11-12V with a 2A load, current limitedSo there you go there's practically no overshoot even when drawing 20W+ out of it, perhaps a little bit with no load but it's almost nothing really.

author: dmmt40
author_rank: Regular Contributor
timestamp: July 29, 2015, 04:34:13 am
content: And finally for the actual operation of the PSU.A feature that I liked is setting up the voltage and current you just need to press the knob once and it highlights the digit you can change, multiple presses changes between digits for fine and coarse adjustment.The overcurrent protection OCP also works fine, in this case if you go above the current limit the output switches off entirely to avoid any damage to your circuit instead of just holding the current.Now for the bad news, one thing that really annoyed me is that the fan is supposed to be temperature controlled and OFF unless it reaches a certain internal temperature but no, the fan is ALWAYS on, yes it’s not very loud but it’s a shame they lied about it, there’s even a sticker at the back of the unit!This is one of the reasons I bought this PSU thinking it would be silent most of the time since I mostly do low power stuff,Inside I couldn’t see a temperature sensor around the heatsink or if there is one they aren’t using it because as soon as you go above a certain power draw (around 20W) the fan goes to maximum speed instantly even if the unit is cool.What I will probably end up doing is hacking some sort of switch since I don't really expect to use it heavily (like many hours a day or getting the maximum power out of it) so it'll be fine I reckon, if anyone's interested I do recommend it, very small, very easy to use, accurate, no overshoot, 30V 5A linear PSU for under $100? yep,worth every penny... just need to fix that fan now agh

author: tautech
author_rank: Super Contributor
timestamp: July 29, 2015, 05:04:34 am
content: Thanks very much for photos etc.In you pichttps://www.eevblog.com/forum/testgear/tekpower-tp3005t-variable-linear-dc-power-supply/?action=dlattach;attach=163223there are 2 white wire connected to what looks like a temp sensor on the heatsink.It does appear to be a temp controlled PSU but not working correctly as you say.

author: dmmt40
author_rank: Regular Contributor
timestamp: July 29, 2015, 05:18:11 am
content: Yeah, I suspected that was the sensor but wasn't suremakes me wonder why they didn't implement it and how easy it would be to reprogram the PIC (there's an unconnected header right next to it) maybe I should ask Tekpower about it.

author: tautech
author_rank: Super Contributor
timestamp: July 29, 2015, 05:35:24 am
content: Quote from: dmmt40 on July 29, 2015, 05:18:11 amYes you should, IMHO the unit is faulty.

author: MarkF
author_rank: Super Contributor
timestamp: July 29, 2015, 12:40:28 pm
content: Nice job dmmt40. Thanks for all the pictures.

author: ddbb199
author_rank: Newbie
timestamp: March 21, 2016, 09:58:04 pm
content: I've bought the TP3005T after seeing the good power up transient that dmmt40 had posted, and now I have some questions.I did the same test with no load at 5v and seems like 80% of the time there's a short spike (sometimes >8v) before the output start ramping. (I'll try to attach the waveform soon)Also there seems to be a transformer vibration sound when I push the power button. Is that because AC main voltage is not at 0 crossing when I press the button? Is it normal and can it be avoided?Lastly I noticed that the red plastic washer on the screw that holds the laminates in place was broken so that the screw is touching the laminate. Would that be a safety issue that the laminate is not isolated?p.s. I just starting out diving into the electronic hobby and have learnt a great deals from you all. Thanks in advance.

author: Rob Sims
author_rank: Regular Contributor
timestamp: August 14, 2016, 12:18:23 am
content: I have the same power supply. Question, does it have voltage and current adjustment on the display to calibrate the unit in case it ever drift?

author: dmmt40
author_rank: Regular Contributor
timestamp: August 15, 2016, 04:57:01 pm
content: Quote from: Rob Sims on August 14, 2016, 12:18:23 amNo, it doesn't.

author: Rob Sims
author_rank: Regular Contributor
timestamp: August 16, 2016, 07:54:16 pm
content: But how is this power supply is being calibrated then?. I'm asking this, because i'm concerned that if the readings of the unit ever drift, I have to send it away with the possibility that it never returns to me again. I fi can calibrate it myself it would be nice.

author: dmmt40
author_rank: Regular Contributor
timestamp: August 19, 2016, 10:43:54 pm
content: Quote from: Rob Sims on August 16, 2016, 07:54:16 pmmmm I don't know actually!maybe it's software calibrated?Last time I checked my specific unit the voltage was spot on with my multimeter, but current reads a bit low, still within spec but very close to the limit.I don't know if it's possible without some hardware modification, but who knows maybe there's a secret menu or something were you can adjust things. The best way to know is just asking the manufacturer or looking around to see if someone has done it. I would certainly be interested as well!Looking at my earlier posts I can see that I reviewed it around a year ago, so if you want I can check readings again to see how much it has drifted in all this time.Dan

author: tautech
author_rank: Super Contributor
timestamp: August 19, 2016, 10:49:09 pm
content: Quote from: Rob Sims on August 16, 2016, 07:54:16 pmDo they have I/O ports?Remote calibration/adjustment.

author: bitseeker
author_rank: Super Contributor
timestamp: August 19, 2016, 11:04:13 pm
content: Since there aren't any external communication ports, it's probably calibrated with offset values that are set via the white connector near the middle-left of the front panel PCB, beside the microcontroller.

author: Rob Sims
author_rank: Regular Contributor
timestamp: August 22, 2016, 12:24:13 am
content: I have just received a drawing of this power supply from the manufacturer. I have attached the diagram. Please, I want to be updated on how to calibrate it. Of course if someone finds out how to. If it ever drifts, I want to calibrate it myself.

author: Rob Sims
author_rank: Regular Contributor
timestamp: August 22, 2016, 12:41:55 am
content: Forgot to mention that the manufacturer said that there is no calibration that can be done manually. So I guess it's all done by software. I've asked if there is a menu. As soon as I've received an answer I will post it.

author: Dwaine
author_rank: Frequent Contributor
timestamp: August 22, 2016, 02:59:29 pm
content: Looks really good for $39.99. The only thing I noticed was that cap flapping in the wind on that bottom board. They even used Loctite...

author: Dwaine
author_rank: Frequent Contributor
timestamp: August 22, 2016, 03:00:38 pm
content: For the people which have purchased this power supply; Does the fan actually stay on all the time. Or was it a one off?

author: Rob Sims
author_rank: Regular Contributor
timestamp: August 22, 2016, 07:41:34 pm
content: No the fan stays on the whole time. Under 1 amp it's silent but above 1 amp you hear the sound of a propeller plane.

author: Rob Sims
author_rank: Regular Contributor
timestamp: August 22, 2016, 09:06:59 pm
content: I have posted the diagram of this PSU. Thought somebody already knew how to calibrate this PSU. Still nobody figured it out. Where are all the geniuses??

author: bitseeker
author_rank: Super Contributor
timestamp: August 22, 2016, 11:06:30 pm
content: The manufacturer already said it's not possible to adjust it manually and the schematics confirm this. My prior post indicated a likely method that the manufacturer uses.

author: Rob Sims
author_rank: Regular Contributor
timestamp: August 23, 2016, 12:51:17 am
content: Ok

author: Rob Sims
author_rank: Regular Contributor
timestamp: August 23, 2016, 09:09:31 pm
content: Did somebody already cracked the code??

author: bitseeker
author_rank: Super Contributor
timestamp: August 23, 2016, 11:23:16 pm
content: Not that I've heard nor seen. Go for it. You could be first.

author: Rob Sims
author_rank: Regular Contributor
timestamp: August 24, 2016, 12:33:32 am
content: Ok Bitseeker, i'll try my friend.

author: crazyguy
author_rank: Regular Contributor
timestamp: August 24, 2016, 12:47:48 am
content: Quote from: Rob Sims on August 24, 2016, 12:33:32 amThis PSU is not popular on eevblog. No need to crack it, You have the PSU, you can rewrite the software yourself.

author: Rob Sims
author_rank: Regular Contributor
timestamp: September 04, 2016, 09:22:05 pm
content: Anyone aleready know how to calibrate this unit?Where do we begin to rewrite the software???

author: george-151
author_rank: Newbie
timestamp: January 15, 2017, 07:59:03 pm
content: Quote from: dadler on July 18, 2015, 10:08:06 pmYes. All these Power Supplies (including Tekpower) are rebranded from MCP (http://mcpsh.com)Check the new modelshttp://mcpsh.com/M10-QS_Series.html

author: pascal_sweden
author_rank: Super Contributor
timestamp: January 15, 2017, 08:13:04 pm
content: Who says that MCP is the OEM manufacturer of these power supplies?Many of these Chinese power supplies with triple voltage outputs start with HY in their model number.This might suggest that Hyelec is the original manufacturer.https://hyelec.en.alibaba.com/product/324236617-50031735/HYELEC_HY3005_3_linear_mode_LAB_DC_POWER_SUPPLY.html