Review: Tekpower TP3005D-3 Power Supply Teardown - Page 1
Forum section: electronics / general

author: loneoceans
author_rank: Contributor
timestamp: November 24, 2014, 01:43:20 am
content: I recently bought a Tekpower TP3005D-3 Bench supply (3 channel, 30V 5A) for $185 on Amazon.com. I found reviews / teardowns by members here to have been very useful, so I thought I would give my own review of this power supply. I thought it would be a good idea to compare this one with a similar Mastech model by jamesp15here.I posted a page on my website for more details:http://loneoceans.com/labs/tekpower/I also wanted to point out that despite their similar price and appearance, internally it looks very different from the common Mastech/Dr. Meter supplies around.Short Review for the TP3005D-3:This is a completely different product from the similar-looking Mastech / Dr. Meter HY3005F with much better internal construction, a nice big toroid transformer, and measured 6 - 8mVpp CV regulation (well within the 20mVpp specification) at 20Mhz bandwidth. Output goes up to 32V per channel, uses a generous amount of TO247 TIP3055 transistors with a well-designed active cooling system. I have tested each channel with the largest load I have at the moment at about 5.2A at 29.6V per channel, which is impressive. Negligible overshoot (if any) which basically disappears with any load. The things I want to be improved the most would be a selectable switch for 240V operation, and multi-turn potentiometers for voltage / current control. Overall, much better than I had expected and an excellent value compared to any other product for sub $200.Bought on Amazonhereand comes with one year warranty from their distributor, KaitoUSA. Overall, I think I can put my stamp of approval for recommendation!Feel free to ask me questions! Thanks everyone.

author: tknx
author_rank: Contributor
timestamp: November 24, 2014, 04:36:12 pm
content: Thanks for the review - In another post - I asked about looking for a PS for automotive LED light work with some flexibility for other projects. What is your take on this PS for that sort of usage? It seems that you don't find it all that precise, but the Rigols are too much $$$.I like that it is floating, it seems to have sufficient range.I don't like that it overshoots.I suppose you could change out the displays for LEDs and the potentiomaters for multi-turn.

author: loneoceans
author_rank: Contributor
timestamp: November 24, 2014, 05:50:45 pm
content: Quote from: tknx on November 24, 2014, 04:36:12 pmI have no idea what sort of current draw a car LED light would have, but if you're talking about brake / signal LED replacements, I believe they would be drawing on the order of 30 to 100mA at ~11 to 14V or so and should have some sort of internal current limiting anyway. I.e. there is no reason why you would need a precision power supply given that the supply the bulb will be running in (in the car) is nowhere near precise. I would say a cheap supply like this is sufficient for a vast majority of hobby work, and if you're not sure if you need a precision supply, you probably don't.Otherwise, if I was looking for a good supply that will last me for the next decade, I'll definitely pick up one of the Rigols.If you need something accurate within +-10A and +-0.1V, the LCD display is sufficient, and as you can see from the photos, the adjustment pots can be easily swapped out to multiturn pots which I plan to do so. I'm actually starting to like the LCD display just because the electro-luminescent display looks really quite nice in real life!Most supplies should be floating which makes it easier when probing stuff so you don't need to worry about loops and all that, and also allows placing the supplies in series for example to make positive and negative rails.As for overshoot / transients, I think this is about in-line with all the low-end supplies, but I don't think it's much of a problem since I've always erred on the side of caution and not connect circuits directly to the supply when turning it on / off. That said I wouldn't exactly call this Tekpower to have an 'overshoot' problem at all. If you watch Dave's review on the Rigol, it also has turn-on transients which could be a problem with very sensitive circuits. In all, what I concluded in the review was a supply that was basically in-line with the performance I was expecting, but with better construction than others in the same price point such as the Mastech. I think I'll go play around with it a bit more and do more tests on turn-on performance as well as load performance.Tknx, I read your post on a PSU for testing HID bulbs for cars. You'll need a beefy supply for those since they draw between 4 to 8A or so at 12V, and require a HID lamp ballast for starting and then limiting the current draw in the bulbs. I'm not sure what sort of turn-on current is required to get the lamp started up but it seems like this supply with two outputs in parallel is capable of handling that. If the starting burst requires too much current, you can add a battery or large capacitor in parallel with the output to help in the initial current surge.

author: tknx
author_rank: Contributor
timestamp: November 24, 2014, 05:55:38 pm
content: For interior LEDs - a Nichia 219 would draw 100mA at the low end for a vanity light...

author: saturation
author_rank: Super Contributor
timestamp: November 25, 2014, 02:11:09 pm
content: A better PSU over same vintage Mastech variety, it says a lot about state of Chinese manufacturing too. I'm less a fan of the LCD, and prefer LED, in bench instruments because of visibility, but I'd tolerate LCD for improved internal quality of the PSU. I'd really like to see how this PSU peforms near rated load over 8 hours or so, that would be a better test of its capability. Without running it over time you can be sure the parts will hold up to heat and continue to regulate properly, test its thermal design and safety. I burned my Mastech at 30V 2A for 24 hours before I put it into service fleet.Panel meters are typically bought now as pre-assembled modules. The Mastech variety used be custom PCBs that were hand soldered. In the early days, these Mastech supplies had decent all hand assembly:https://www.eevblog.com/forum/reviews/lw-dqgs-power-supply-review-and-teardown-cautionsafety-risks!!!/msg58005/#msg58005Panels appear to be all automated assembly, showing rising labor costs over machine costs.The actual power output section still appears hand assembled but well done.One key advantage of all older technology and design, from the power modules to the panel meters, is its easier to fix should it break, given the no-name of the unit other than the warranty supplied by the seller. Even if through hole parts no longer are made, its easier to jury-rig SMT into a through hole space that vice versa. A lot of space is wasted inside these PSU as the chassis are mass produced with through hole still in mind, and used by many PSU makers.

author: loneoceans
author_rank: Contributor
timestamp: November 26, 2014, 07:13:14 am
content: Quote from: saturation on November 25, 2014, 02:11:09 pmHey Saturation, thanks very much for your helpful insights! I also prefer an LED readout but like you said, I'd take the better internal construction over the LEDs. Thankfully the LCD contrast was better than I had expected (though contrast drops significantly if you're viewing it from above). Thanks for your suggestions as well and I will see if I can do a heavy load test on the supply for a few hours to see how well it does.The photos you showed in the link do look like a better construction than what I've seen online for the more recent Mastech teardowns. On an Amazon review for the Mastech, I saw this comment on a 1 star review for a Mastech power supply:"This 1 star review is very helpful to many people, because so many sellers are selling their low cost and low quality power against this listing.Tekpower was the Mastech brand before no one knows Mastech , we are the first one to bring the brand to the US market, but Masetch brand is being used by many factories in China and the quality is different from each one, so we cannot control the quality on Mastech brand. We create our Tekpower brand to guaranty our Power Supply with highest quality in the industry.So, If you received a power with other brand than Tekpower, you are not guaranteed with the quality.Tekpower Customer Care Team"So it does look like Tekpower might be different from Mastech or the other cheaper brands, but I'm really not sure. Again I want to point out that if you're looking for a proper bench supply, you should not be looking at these and I would recommend you pick up a Agilent/HP/Keysight one or a Rigol. But for general hobby use, I'm very happy with my Tekpower for now! More to come soon as I do more tests.

author: GEuser
author_rank: Frequent Contributor
timestamp: November 26, 2014, 10:34:09 am
content: A Lime coke? I don't think I have seen one of those yet , I'm out rural and don't go out/get about much , we had a Cherry one a while back .For that price I like the P/S , it looks well thought out , cheers ...

author: saturation
author_rank: Super Contributor
timestamp: November 26, 2014, 01:15:29 pm
content: Thanks for this. I do own a TekPower item but its clearly a rebadged Array model electronic load, something you may want to consider having. I do hope they do better in protecting the brand name compared to Mastech.See our Power Designs and the old precision HP power supplies thread on eevblog, you may find that these 200uV or less regulated stable power supplies can outperform most anything today even the production E series Agilent/Keysight PSU models. Its only real failure is that they are not downprogrammable and have limited slew rates for pulse applications and the old Power Designs use current limiting shutoff rather than switchover to CC mode.Quote from: loneoceans on November 26, 2014, 07:13:14 am