Looking for new alternative to replace old Philips PE1542 DC power supply - Page 1
Forum section: electronics / testgear

author: pascal_sweden
author_rank: Super Contributor
timestamp: October 06, 2014, 09:06:00 pm
content: Hello,I am looking for a new DC power supply which has the same capabilities as the old Philips PE1542.What I am looking for in particular:1) Soft start: no overshoot (don't have to disconnect power supply from target circuit before powering up)2) All grounds should be floating: not a common ground between 2 channels (e.g. Rigol does this)3) Channel 1: 0-20V 0-1A, Channel 2: 0-20V 0-1A, Channel 3: 0-7V (or 5V fixed) 0-3A4) Individual Power/Current switch per channelI have not managed to find a good equivalent in the Rigol or Siglent power supply series, as they all seem to have a common ground shared between 2 channels, and most Rigol and Siglent models actually have overshoot during powering up (no soft start).Please advise on a new DC power supply that has the same specs as the old Philips PE1542. See requirements above.It does not have to be digital, and it's okey to have analog VU meters. This is actually nice retro look.I am looking for a factory new DC power supply.Finding an old Philips PE1542 on Ebay is very easy, but the Elcos are probably dried out, and maybe other parts have degraded as well? Any comments here regarding which parts would have degraded? Only the Elcos or more? With more feedback on those parts to be replaced, this path could become a viable option again: refurbishing a unit from Ebay.Still it is important to find a factory new alternative. Hard to believe there is no alternative (better or same specs) for a power supply that is over 30 years old. Any specific recommendations for a factory new DC power supply which has the same capabilities as the old Philips PE1542?(soft start, ALL grounds floating, 3 channels, individual power/current switch, acceptable price range: 100-200 USD)Thanks,Pascal

author: guido
author_rank: Regular Contributor
timestamp: October 06, 2014, 10:25:39 pm
content: I have two of those philips supplies. I have replaced the elco's on the pcb's, but not the big main ones. Maybe replaced more, can't remember exactly. But there is not much in them that can go wrong.Had to fix one of them. Not a big problem as documentation is available (723 design). They work fine now. And yes, it is very nice that all GNDs are independent.

author: Kjelt
author_rank: Super Contributor
timestamp: October 07, 2014, 08:30:57 am
content: Hard to find, one of the assembly factories had these as test power supplies, they replaced them 7 years ago with €500+ SM supplies and after 1 week sent them all back because of the overshoot (that lesson cost a lot of samples).They refurbished the old Philips supplies and still use them todayYou could look with Delta powersupplies but don't think they will meet your third requirement.As an alternative you might end up buying three independent power supplies instead of one, which also has huge benefits.

author: pascal_sweden
author_rank: Super Contributor
timestamp: October 08, 2014, 02:41:09 pm
content: Maybe HP (Agilent) does produce something similar new today?BTW: When did Philips stop making scopes, wave form generators, DC power supplies and other lab equipment? I really liked their design with the black and red line logo

author: HighVoltage
author_rank: Super Contributor
timestamp: October 08, 2014, 03:23:59 pm
content: Quote from: pascal_sweden on October 08, 2014, 02:41:09 pmThey stopped, after they got taken over by FLUKE.First they called it the "Philips Fluke Test and Measurement Alliance".Then the Philips name slowly disappeared.And then all their good equipment disappeared.As far as I know, there is only one item still in production of the Philips designedequipment,it is the RCL Meter PM6306In regards to the Philips DC PSU, I would keep it.I have the same one and love it.Interestingly, mine looks a little different. (see picture)I also exchanged all the caps inside and it just works perfectly all the time.Having the analog meters for current and looking at a current trend is reallyhelpful and can not be found in any modern PSU, that I have tested.

author: guido
author_rank: Regular Contributor
timestamp: October 08, 2014, 04:58:50 pm
content: Yes, there are two versions. Yours has a fixed 5V, but the other channels go up to 32V.The more common version is 0-7V, but the other channels only go to 20V.Mine have a blue band.Actually, just like the picturesAnd both are called PE1542...

author: HighVoltage
author_rank: Super Contributor
timestamp: October 09, 2014, 11:04:59 am
content: Quote from: guido on October 08, 2014, 04:58:50 pmIsn't that weird?Mine came from the German Army (BUND)May be it was special edition made by Philips at the time, just for the Army.Here is a picture of the back of my unit.

author: pascal_sweden
author_rank: Super Contributor
timestamp: October 09, 2014, 02:41:38 pm
content: Maybe we have identified a business opportunity here.Release the PE1542 again. Schematics are available anyhow.We should ask Rigol to launch a Rigol PE1542, which keeps all features and looks of the original Philips design =)

author: G0HZU
author_rank: Super Contributor
timestamp: October 09, 2014, 03:55:23 pm
content: I bought a PE1542 about 15-20yrs ago for about £15 and it is still going strong. It's a nice compact unit. The only minor niggle is that the outputs aren't switched but you can add external switches (as I sometimes do).In terms of value for money this PSU is hard to beat.

author: guido
author_rank: Regular Contributor
timestamp: October 09, 2014, 04:27:00 pm
content: In case you work on one, these are the potentiometers:Top: meter adjustI adjust - V adjustBottom: supply adjustVmin - Vmax - Imax - Imin

author: pascal_sweden
author_rank: Super Contributor
timestamp: October 09, 2014, 09:03:40 pm
content: Same evolution for all electronic equipment... industry has tendency to make things cheaper and sacrifice on quality and reliability.

author: pascal_sweden
author_rank: Super Contributor
timestamp: October 10, 2014, 09:36:51 am
content: To clarify my point a bit better: manufacturers are tempted to throw in a lot of bells and whistles before getting the basics right.Of course it is nice to have a power supply which can be controlled through LXI or other protocols, for doing automated measurements. But these are nice to have, and should be added only after the must haves are verified working. Must haves are no overshoot, separate independent grounds for all channels, accurate read out, and stability.Simplicity is an important aspect as well. What is the point of adding bells and whistles if they affect the user friendliness for day to day use of the device.

author: eurofox
author_rank: Unknown
timestamp: October 10, 2014, 09:54:00 am
content: I just check again my Rigol DP832A if there is any overshoot when the output is selected.There is NO overshoot, I check the 3 outputsThis is simply a very good power supply.Before I got as well the same Philips like you have, is a good power supply but I wanted something more modern and with more possibility's.

author: pascal_sweden
author_rank: Super Contributor
timestamp: October 10, 2014, 10:01:55 am
content: If they would make the 3 grounds all separate, then indeed it might be a good power supply.Who submits a Change Request? =)

author: eurofox
author_rank: Unknown
timestamp: October 10, 2014, 10:12:50 am
content: Quote from: pascal_sweden on October 10, 2014, 10:01:55 amI just check the ground connection with power supply on, all output on and with ohm meter:Channel 1, no connection between - and - from 2 and 3Channel 2, no connection between - channel 1 but connection with - of channel 3I hope this clarify this issue.

author: pascal_sweden
author_rank: Super Contributor
timestamp: October 10, 2014, 10:16:05 am
content: Thanks for the clarification! Yes, I am aware of that implementation.Here is the official Change Request towards Rigol, based on your formulationChannel 1, no connection between - and - from 2 and 3Channel 2, no connection between - and - from 1 and 3Channel 3, no connection between - and - from 1 and 2

author: eurofox
author_rank: Unknown
timestamp: October 10, 2014, 10:28:49 am
content: Quote from: pascal_sweden on October 10, 2014, 10:16:05 amLets put it this way, only channel 2 - is connected to channel 3 -A power supply with all - connected together is useless if you need a power rail for op amp with GND and +15 and -15

author: pascal_sweden
author_rank: Super Contributor
timestamp: October 10, 2014, 10:31:58 am
content: Maybe you misunderstood. I am asking for all GNDs to be independent, separate.I am not asking for all GNDs to be connected =)

author: eurofox
author_rank: Unknown
timestamp: October 10, 2014, 10:37:39 am
content: Quote from: pascal_sweden on October 10, 2014, 10:31:58 amYes I understood, I just wanted to clarify that only - 2 and 3 are connected and never got problem with this, channel 3 is usually for the logic rail and should be common with analog GND but of course is up to you to put your specifications.

author: jancumps
author_rank: Unknown
timestamp: October 10, 2014, 11:11:54 am
content: Quote from: eurofox on October 10, 2014, 09:54:00 amyeah. I bought yours.

author: pascal_sweden
author_rank: Super Contributor
timestamp: October 10, 2014, 09:12:15 pm
content: There is a guy on Ebay, based in Germany, who has over 50 units of these in his warehouse.He is asking around 75 euro per piece. Is this a fair price? I am still waiting on confirmation regarding level of testing which they perform (functional testing only, or also visual inspection inside) and whether they give any warranty at all or nothing.

author: jancumps
author_rank: Unknown
timestamp: October 10, 2014, 09:47:44 pm
content: Quote from: pascal_sweden on October 10, 2014, 09:12:15 pmFor what model? The Philips or the Rigol?

author: pascal_sweden
author_rank: Super Contributor
timestamp: October 11, 2014, 10:44:54 am
content: 50x Philips PE1542 in warehouse. 95 euro/piece. No confirmation yet on origin of these units, level of functional testing, visual cap inspection inside, and warranty coverage.

author: Kjelt
author_rank: Super Contributor
timestamp: October 11, 2014, 10:52:13 am
content: Depends indeed on the age and condition. I would assume you have to do some maintenance, change the smaller elco's, check the potentiometers, or clean them or replace them (they are cheap anyway since they are not multiturn). These units have come from closed plants/factories esp. older Philips business units.They were sold for around €50 to €75 on fleamarkets so this is a reasonable price. Problem is the shipping costs. Still it is way cheaper then redesigning your own pcb, buying all components as transformers etc. On the other hand the China PSU with digital V and A meters are the same price new. So I would still bid lower then asking price.

author: pascal_sweden
author_rank: Super Contributor
timestamp: October 11, 2014, 12:43:20 pm
content: Thanks for the feedback!Quote from: Kjelt on October 11, 2014, 10:52:13 amCan you indicate a China PSU which has 3 DC voltage outputs, which does not exhibit overshoot during start-up, and where each ground is totally independent and not shared? I haven't found such one. Nothing beats the Philips PE1542 in that respect

author: eurofox
author_rank: Unknown
timestamp: October 11, 2014, 01:23:20 pm
content: Give a look on ebay France, there 2 recent Hameg PS with 3 outputs, I don't no if ground is isolated from each other.

author: pascal_sweden
author_rank: Super Contributor
timestamp: October 11, 2014, 04:05:17 pm
content: Do you mean Hameg HM 8142?What does "sense" mean? Is this ground?From this configuration it makes me conclude that all outputs are floating, and not connected to ground. Can someone confirm this?Why are there two "sense" connectors on the third voltage output? I am confused about this.It actually has nice expansion options (e.g. IEEE-488 GPIB interface). Quite expensive power supply though. In the range of 300-400 euro on Ebay for a second hand unit. My budget for a used power supply is only up to 75-100 euro.

author: eurofox
author_rank: Unknown
timestamp: October 11, 2014, 05:19:30 pm
content: Quote from: pascal_sweden on October 11, 2014, 04:05:17 pmYep "stoere pengar"With 75€ is just enough to buy 3 beers in Sweden

author: SeanB
author_rank: Super Contributor
timestamp: October 11, 2014, 05:53:12 pm
content: 75 Euro here would buy you 5 cases of 24 340ml beers. 4 cases if you wanted H US beer, or 3 cases of Guinness. It would also buy 4 cases of 12 quart sized returnable bottles.Or you could go on the brewery tour, which includes a few free draught beers in the pub, and for a 1 hour drive you can go to the Nottingham road micro breweries tour.note does not include plane fare here, airport taxi or accommodation of your choice. If you are here on a Saturday i will take you there and back, as I do not drink so can drive........

author: eurofox
author_rank: Unknown
timestamp: October 11, 2014, 06:12:43 pm
content: Quote from: SeanB on October 11, 2014, 05:53:12 pmI visit Sweden many time on business trips, beer is extremely expensiveAlready in a bar in my country it is 1,5€ for the cheapest beer and in Sweden it could be now 4-5€, last time I was in Sweden was 4 years ago and I don't remember.But Sweden is a nice country with nice people

author: eurofox
author_rank: Unknown
timestamp: October 11, 2014, 06:23:44 pm
content: Quote from: pascal_sweden on October 11, 2014, 04:05:17 pmThe sense operation allows for compensation of voltage drop on the leads between the supply and connected load.

author: pascal_sweden
author_rank: Super Contributor
timestamp: October 11, 2014, 06:31:53 pm
content: Can you explain this with a drawing?Jap... hier in Zweden geen goedkope jupiler of stellaIk ben trouwens Belg van origine... maar inmiddels Zweedse nationaliteit.. woon intussen ook in Noorwegen.. daar is alles nog 2x zo duur als in Zweden

author: Andy Watson
author_rank: Super Contributor
timestamp: October 11, 2014, 06:46:55 pm
content: Quote from: pascal_sweden on October 11, 2014, 06:31:53 pmDave explains here what the problems is: fast forward to about 14 minutes.

author: eurofox
author_rank: Unknown
timestamp: October 11, 2014, 07:13:34 pm
content: Quote from: pascal_sweden on October 11, 2014, 06:31:53 pmWaw now you are near Noordkaap, I was there once in the middle of the summer and it was very cold

author: SeanB
author_rank: Super Contributor
timestamp: October 11, 2014, 07:21:33 pm
content: Quote from: eurofox on October 11, 2014, 07:13:34 pmCome here in mid summer ( typically February) and you are quite likely to die from heatstroke. Then you can go to the hotter places. Coastal weather is quite mild due to the sea, though today I would not recommend swimming in it, seeing as the waves are breaking about 3km offshore and there are around 30 container ships waiting to get into and out of port. Even the surfers are staying out. one surfer I knew went to the UK, and went to the UK's premier surfing spot. Looked at the beach of pebbles, the guys in mid summer in drysuits and the mill flat water and thought "Yeah, riiiiiight". I wear a wetsuit in winter only when it gets cold, or below 20C. Rest of the time boardshorts and a tshirt to keep the sun off.

author: HighVoltage
author_rank: Super Contributor
timestamp: October 11, 2014, 07:39:45 pm
content: I also have one of these new models Hameg / Rhode & Schwarz PSU HM8143They are extremely nice and the grounds are NOT connected.But they are a little bulky with the wide size, to fit this Hameg standard.I would have preferred the standard Keysight size.But well, besides this, it is a well built PSU and I can only highly recommend it.

author: pascal_sweden
author_rank: Super Contributor
timestamp: October 11, 2014, 11:39:42 pm
content: Yes, very nice to use, but list price seems to vary from 650-1200 euro. Quite over budget.We are talking here about a DC power supply. How come this is so expensive? =)Then I prefer the 30 year old Philips PE1542 listed as 95 euro on Ebay.

author: G0HZU
author_rank: Super Contributor
timestamp: October 12, 2014, 01:18:03 am
content: QuoteThe PE1542 is a neat little PSU but it isn't worth 95 Euro in 2014. I would think the PSU is probably worth about £30 here in the UK. I paid just £15 for mine back in the 1990s.

author: HighVoltage
author_rank: Super Contributor
timestamp: October 12, 2014, 09:12:44 am
content: TopLoser just sold one of the HM8143 PSU here on the forum for £450https://www.eevblog.com/forum/buysellwanted/fs-%28uk%29-hameg-hm8143-3-channel-arbitrary-psu-and-electronic-load/It is an absolute top PSU, made in GermanyAnd, if you combine it with the Hameg power meter HM8115-2 it is a very powerful setup.http://www.hameg.com/0.147.0.html

author: wraper
author_rank: Unknown
timestamp: October 12, 2014, 10:07:51 am
content: Thurlby thandar shoud have what you needhttp://www.tti-test.com/products-tti/psu/psu-bench.htmI have a PL303QMD and it definitely don't do nasty things. No overshoots, outputs disconnected by relays.

author: Mr Simpleton
author_rank: Unknown
timestamp: October 12, 2014, 02:08:51 pm
content: Hameg 7042 looks pretty neat and costs ~€600+VAT... but I really like the Toellner PSU. We have a few at the office and never gave any problems.Here at home I do have the "not so common" R&S. Got it for a song at the local hamfest

author: pascal_sweden
author_rank: Super Contributor
timestamp: October 15, 2014, 06:36:42 pm
content: Yes, also a good power supply, but again we are talking here about 1000 euro price range.So, it looks like if you want triple power supply with no overshoot and 3 floating outputs, you either need to go for a 100 euro power supply that is 30 years old, or you go for a brand new power supply that is going to cost you over 1000 euro.Isn't there anything new out there, without overshoot, and with 3 floating outputs, that is closer to the 100 euro range, just like the 30 year old Philips PE1542? We are only talking here about a power supply, and 1000 euro is ridiculous, as you can get a brand new spectrum analyzer these days for that amount of money

author: G0HZU
author_rank: Super Contributor
timestamp: October 15, 2014, 07:20:56 pm
content: How about a TTI PL154 and a TTI TS3022S combo?TTI PL154 = 15V 4ATTI TS3022S = Dual 32V 2AI recently paid £50 and £95 for these and this gives a far higher spec than the PE1542 plus you aren't tied to having all three supply rails in one place.You get to see fairly high resolution current and voltage (digital) displays at the same time. You get to set the current limit very accurately. You get switchable outputs and also current sensing if required. You also get something that is only a few years old rather than 30 years old and a bit flakey.All this for £145 isn't bad.

author: pascal_sweden
author_rank: Super Contributor
timestamp: October 16, 2014, 05:10:40 pm
content: Not bad, but still over budget

author: pascal_sweden
author_rank: Super Contributor
timestamp: October 17, 2014, 08:19:06 pm
content: Based on the available schematics, it would be possible to spin a new PCB design and built new PE1542 DC power supplies anno 2014.I wonder how much the Bill-Of-Materials would cost, but it would be certainly very cheap.Maybe it can be made for less than 50 euroNow here is what we can call a business opportunity!

author: eurofox
author_rank: Unknown
timestamp: October 17, 2014, 08:56:21 pm
content: Quote from: pascal_sweden on October 17, 2014, 08:19:06 pmBudget for 2 beers in Norway

author: oldway
author_rank: Super Contributor
timestamp: October 18, 2014, 01:41:11 pm
content: Repair and service of old Philips power supplies, as the PE1542, is now provided by Alpha Technologies at Waver / Belgium.http://www.alphatechnologies.eu/services/repairs

author: pascal_sweden
author_rank: Super Contributor
timestamp: October 19, 2014, 10:43:34 pm
content: What about this power supply from the french manufacturer ELC?http://elc.fr/en/online-quotation/adjustable-and-multiple-power-supplies/8-triple-output-stabilized-power-supply.htmlSelling price is 500 EUR (Exclusive VAT).Anybody experience with this brand?

author: Kjelt
author_rank: Super Contributor
timestamp: October 20, 2014, 06:11:42 am
content: Quote from: pascal_sweden on October 19, 2014, 10:43:34 pmYou give your own answer:Quote from: pascal_sweden on October 16, 2014, 05:10:40 pm–-----------------------Quote from: pascal_sweden on October 17, 2014, 08:19:06 pmThe PCB can be redesigned in SMD technology and the single turn pots arent expensive. However the main transformer would still cost due to high copper prices quite some money. And the large capacitors would also be expensive, and then the meters and metal casing...... 50 euros forget it.You,re better off buying a 2nd hand and rebuilding that IMO.

author: pascal_sweden
author_rank: Super Contributor
timestamp: October 21, 2014, 06:49:02 pm
content: Did Rigol solve the overshoot issue in the latest firmware update of the Rigol DP832?What other known issues are still present in the Rigol DP832?Can the Rigol DP832 be converted into a full DP832A through a SW hack?Does this still work in the latest firmware?If this power supply would have 3 completely independent outputs (not a common ground between 2 outputs), it would be a valid candidate to replace the Philips PE1542.Does anybody out here have good contacts with the product department of Rigol? Maybe we can suggest them to introduce this improvement in their future line, to have 3 completely independent outputs.

author: G0HZU
author_rank: Super Contributor
timestamp: October 21, 2014, 09:31:22 pm
content: QuoteCome on...You can't realistically compare a PE1542 and the Rigol PSU...The Rigol offers modern functionality like remote control and very accurate setting of voltage and current and it has a higher voltage and current capability. It's best suited for low cost ATE setups. Despite all this I think it is a horrible looking thing with a crazy front panel design and I'd not want to have one on my work bench because it looks so loud and tacky and the user interface would drive me potty. Its best feature (for me) would be the programmability.I've had my old PE1542 here since the 1990s and it is a very good but basic PSU that only cost me £15. However, you can't set the current limit very accurately at low currents, it doesn't have switchable outputs and the analogue dials can't always be trusted to be accurate. Obviously, it doesn't offer remote control either. The rotary controls do not have a quality feel to them. However, as a basic workhorse for low power hobby projects it is still a very capable little PSU and worth buying if you can spot one at a bargain price...

author: HighVoltage
author_rank: Super Contributor
timestamp: October 21, 2014, 09:47:32 pm
content: Quote from: G0HZU on October 21, 2014, 09:31:22 pmI so agree with you on this one!

author: pascal_sweden
author_rank: Super Contributor
timestamp: October 21, 2014, 10:31:05 pm
content: I was also considering the Atten PPS3205T-3S power supply, until I watched the review video on EEVblog.While the power supply is very precise and meets all the ratings, the user interface is a hazzle.With just a little bit more effort they could actually put a nice product on the market. This applies to the other Chinese suppliers as well. What I sometimes wonder is why they don't hire a Western engineer to help improve the product before they spin these devices and roll them from the assembly line =)

author: jancumps
author_rank: Unknown
timestamp: October 22, 2014, 05:15:19 am
content: Quote from: oldway on October 18, 2014, 01:41:11 pmHey, the PE1542 was made in Waver. Says so on the back of mine.

author: pascal_sweden
author_rank: Super Contributor
timestamp: October 25, 2014, 09:58:25 pm
content: I have decided to stick with the Philips PE1542 DC power supply.My remark about the chinese manufacturers still holds:What I sometimes wonder is why they don't hire a Western engineer to help improve the product before they spin these devices and roll them from the assembly line =)There is nothing wrong with the overall functionality of Rigol and Atten DC power supplies. In fact it is quite impressive what they can do for such little money.Hower with only little extra efforts they could make the Rigol DP832 or the Atten PPS3205T-3S DC power supplies much better: no overshoot during start-up, isolated outputs (no common references between 2 outputs), proper working serial and parallel connection options (with verified power output on the combined outputs), verified user friendly graphical user interface.What these manufacturers sometimes forget is to first get the basics right (correct operation, quality, reliability) and only afterwards focus on the bells and whistles (remote control over Ethernet, programming). These extra bells and whistles are NICE TO HAVE, but not must have. The basic correct operation, quality and reliability on the other hand are MUST HAVE.Dave should be a consultant for Rigol and AttenChinese products designed by Chinese engineers, verified and improved by small group of Western consultants, before they are produced in mass quantities, and finally used and enjoyed by the mass of Western engineers.

author: jancumps
author_rank: Unknown
timestamp: October 25, 2014, 10:06:56 pm
content: They don't need western engineers. From my experience working with experts and companies around the world: we're all smart and all well educated.

author: nctnico
author_rank: Super Contributor
timestamp: October 25, 2014, 10:09:16 pm
content: Let's just say that competent engineers are scarse everywhere O0

author: HighVoltage
author_rank: Super Contributor
timestamp: October 26, 2014, 10:20:59 am
content: Quote from: pascal_sweden on October 25, 2014, 09:58:25 pmA few month ago I tested a Chinese sensor that was already in production in China and failed in Germany.The problem was found fast and I suggested to the China based company a change.They came back with the answer, that they still had about 100.000 sensor elements on the shelf, which willlast them a few more month. And after they have been used up, they will gladly improve the parts.It seems that some of these China based companies do not care, if their parts are failing in the west.

author: pascal_sweden
author_rank: Super Contributor
timestamp: April 18, 2015, 04:42:10 pm
content: How come the PE1542 power supply did not have to use any relays to cover the whole voltage range going from 0V to 32V?The new linear power supplies from Mastech, Tekpower or Dr Meter all seem to use up to 3 relays per voltage output to cover the whole range. When the relay switches it even can cause some spikes.Is there anybody out here with a Dr Meter HY3005F-3 power supply in Europe?Could you test with a scope if there are big spikes when you power on the power supply, but also test if there is a spike when the relay switches to another voltage range.

author: pascal_sweden
author_rank: Super Contributor
timestamp: May 11, 2015, 01:53:13 am
content: Wanted to post my question again: The Philips PE1542 is a linear power supply that provides a voltage range up to 30V. Most Chinese linear power supplies that provide the same voltage range contain at least 2-3 relay switches to cover that voltage range. How come the Philips PE1542 does not have any relay switches? Is the design fundamentally different? Both the Philips and the Chinese power supplies are linear power supplies.

author: H.O
author_rank: Frequent Contributor
timestamp: May 11, 2015, 05:19:48 am
content: Hi,It's all about power.I don't have any experience with either supply but I Googled quickly and found that the Philips PE1542 is a 20V, 1A supply (20W) per output (perhaps there are multiple models, I don't know). Your typical Chinese supply like the HY3005 is a 30V 5A supply (150W) per output.Now lets assume both supplies have a 5V margin on the supply voltage and that you set the output to 1V and then short the output.The PE1542 would need to drop 25-1=24V across its regulator circuit while outputting 1A. Dissipating 24W, a fair bit of power but not really a big deal for a hefty power supply.The HY3005 would need to drop 35-1=34V across its regulator circuit while outputting 5A. Dissipating 170W, that's a lot more power.So the HY3005 uses relays to switch in different transformer windings in order to reduce the power loss in the linear regulator. I don't know the details but let's assume there are windings to produce 12, 24 and 35V DC. Now, when the output voltage is set to 1V and the output shorted the supply will only need to drop 12-1=11V across its regualtor circuit, dissipating 55W instead of 170W.

author: bingo600
author_rank: Super Contributor
timestamp: May 12, 2015, 07:39:35 pm
content: I just got 2 "Red" PE1542 for 70€ on *bayI needed some "quiet" psu's for opamp fun./Bingo

author: pascal_sweden
author_rank: Super Contributor
timestamp: May 12, 2015, 07:57:15 pm
content: I see that you are based in Denmark. Cool! Greetings from NorwayDid you score them from France, or what was the country of origin?

author: bingo600
author_rank: Super Contributor
timestamp: May 12, 2015, 08:20:14 pm
content: Quote from: pascal_sweden on May 12, 2015, 07:57:15 pmYupp from France/Bingo