The first time you saw a solid state SMPS - Page 1
Forum section: electronics / general

author: shakalnokturn
author_rank: Super Contributor
timestamp: November 28, 2018, 09:21:56 am
content: I just opened a computer tower (I avoid doing that as much as I can these days!), seeing the 5 phase power supply for the CPU Vcore reminded me that SMPS has matured a lot.The first ever SMPS I got my nose into was as a teen, disassembling a Philips K9 CRT TV. I remember how this shielded box seemed so strange, complex and dangerous.Attached a couple of pictures borrowed from Frank Sharp's excellent website.What was your first encounter with a SMPS?

author: BradC
author_rank: Super Contributor
timestamp: November 28, 2018, 09:45:19 am
content: Quote from: shakalnokturn on November 28, 2018, 09:21:56 amApple ][

author: Kjelt
author_rank: Super Contributor
timestamp: November 28, 2018, 10:36:19 am
content: I think it was when Atari for the ST series switched their external PSU from conventional to smps.I remember that I found the PSU shockingly light in weight and asked twice if it was the right power supply for this machine

author: HighVoltage
author_rank: Super Contributor
timestamp: November 28, 2018, 10:45:08 am
content: I am still surprised these days, how lightweight the modern SMPS are.Just installed a TDK industrial 10A 24V SMPS yesterday and was amazed by the weight and small footprint.My first encounter was also the old Apple computer.

author: GeorgeOfTheJungle
author_rank: Super Contributor
timestamp: November 28, 2018, 11:03:26 am
content: Apple II

author: capt bullshot
author_rank: Super Contributor
timestamp: November 28, 2018, 11:30:51 am
content: Apple //e

author: PA0PBZ
author_rank: Super Contributor
timestamp: November 28, 2018, 11:57:25 am
content: While reading the topic title I thought 'that must be the K9 power supply' and so it is

author: RoGeorge
author_rank: Super Contributor
timestamp: November 28, 2018, 12:07:19 pm
content: Except maybe the relay driven choppers used to power Tesla coils, never seen a SMPS that is not 'solid state'.https://en.wikipedia.org/wiki/Solid-state_electronics

author: CJay
author_rank: Super Contributor
timestamp: November 28, 2018, 12:14:33 pm
content: Thorn 9000 SYCLOPS psu, bloody horrible things.@Kjelt, never seen an ST with an external PSU, didn't realise they made them!!

author: Kjelt
author_rank: Super Contributor
timestamp: November 28, 2018, 12:40:12 pm
content: Quote from: CJay on November 28, 2018, 12:14:33 pmUh now you made me doubt myself but no they did, see picture.The first batch ST520 I bought in (1985 was it?) had the heavy powersupply, I believe the successor 1040 also had it but then had the SMPS powersupply.

author: CJay
author_rank: Super Contributor
timestamp: November 28, 2018, 01:21:08 pm
content: Quote from: Kjelt on November 28, 2018, 12:40:12 pmWell learn something every day, I had no idea an ST with external PSU and floppy even existed!All the ones I got my hands on (and I worked on a *lot* of warranty returns) had internal PSU and FDD.In fact, I think there's a warranty return 1040STFM in my loft complete with bundled games!

author: joeqsmith
author_rank: Super Contributor
timestamp: November 28, 2018, 01:26:36 pm
content: It depends what you classify as a switching supply. I saw some early transistor DC-DC converters in the 70s. These replaced the mechanical vibrators used in some of the old portable radios. They still ran them at the low frequency. I have a computer built in around 71/72 that uses one.

author: Wolfram
author_rank: Frequent Contributor
timestamp: November 28, 2018, 01:35:18 pm
content: Quote from: RoGeorge on November 28, 2018, 12:07:19 pmTube based switchmode supplies were used long before the invention of the transistor. Also electromechanical vibrators and induction coils were widely used to power tube radios and provide spark power from the low voltage battery in cars, respectively.

author: NiHaoMike
author_rank: Super Contributor
timestamp: November 28, 2018, 02:05:36 pm
content: Quote from: RoGeorge on November 28, 2018, 12:07:19 pmDon't forget gasoline engine ignition systems before they went solid state. And the flyback supply in tube TVs.

author: MrMobodies
author_rank: Super Contributor
timestamp: November 28, 2018, 03:21:27 pm
content: Quote from: Kjelt on November 28, 2018, 10:36:19 amI only discovered it when I opened it to put some more simms in and I came across a very large resistor that was broken but it still worked.I came across a room with old equipment and I pulled out the AT power supplies and made my first mistake.Some of them I think were Enlights and they had flimsy aluminium cases.I powered them up without load and they stopped and smoked apart from ones which were Vantecs.

author: coppice
author_rank: Super Contributor
timestamp: November 28, 2018, 04:51:46 pm
content: Quote from: shakalnokturn on November 28, 2018, 09:21:56 amAre you sure that was a K9? I'm pretty sure the K9 chassis generated all the supplies from the line output transformer, with a very elementary supply to get the line output stage going. Its still a kind of SMPS, but it wasn't in a shielded box. It had as much space around it as possible to minimise coupled capacitance to the EHT wiring.

author: bd139
author_rank: Super Contributor
timestamp: November 28, 2018, 04:58:00 pm
content: Quote from: CJay on November 28, 2018, 12:14:33 pmHahaha think it was the same here. Around 1985 but an early-mid 1970s Ferguson TV (think that had a Thorn classis from that line in it). My uncle said I could have it and fix it if I wanted. Turned out it was chock full of those POS lockfit transistors that had gone wonky and had been repaired before a few times apparently. I stripped it for parts in the end. I think my first little FM Transmitter came out of that. I was mostly disappointed that it didn't have a massive HT transformer like the older televisions.The first one I got working again was an Acorn electron power supply that had gone phut around the same time. Fortunately that was a nice and easy one.

author: JPortici
author_rank: Super Contributor
timestamp: November 28, 2018, 05:02:34 pm
content: Actually there was at least one SMPS built around tubeshttps://hackaday.com/2018/09/08/a-switching-power-supply-1940s-style/

author: Cyberdragon
author_rank: Super Contributor
timestamp: November 28, 2018, 06:36:35 pm
content: There were several applications for tube converters (mostly thyratron like that), mostly industrial or military gear. Also, depending on what counts as an SMPS, you could include spark gaps, arc oscillators, rotary spark gaps, Alaxanderson alternators, exc.

author: PA0PBZ
author_rank: Super Contributor
timestamp: November 28, 2018, 07:10:53 pm
content: Quote from: coppice on November 28, 2018, 04:51:46 pmI'm 100% sure it was a K9, the first full solid state color tv from Philips. I repaired enough of those to be sure, and later I even had a spare power supply in my car to swap for a fixed price. If I recall correctly it converted the input AC to a fixed 150V (155?) which powered the line output where indeed the rest of the voltages where created. Oh, and it also fed the degaussing coil. There it is, bottom center:

author: SeanB
author_rank: Super Contributor
timestamp: November 28, 2018, 07:43:19 pm
content: First was a relative of the Phillips G11, which was a common enough TV power supply in the 1980's, and where the common failure was they used 1N4004 diodes on the input which did not like the current spikes.Avionics I did a little with a SMPS that ran off 28V and used a large air cored coil to buck this down to 5VDC, using BUX20 transistors in a TO3 package as the switches. They did not use any capacitors on the output, relying instead on the 100n and 100uF 25V wet tantalum capacitor per board, and the plane capacitance instead, and a 2200uF 63V axial electrolytic on the input side bypassed with a 47uF 100V wet tantalum. Ran IIRC at around 60kHz, using a mix of TTL and LM311 comparators as clock and regulation, and a 6V8 TC reference diode. They also included overvoltage protection, using another 2 6V8 20W stud mount zener diodes on the same frame as the output diodes, in the same size package.2 identical power supplies in the same case, one was always on, providing the auxiliary logic and RAM with 5V power, at around 20A. The other was switched at 400Hz, used to power the ALU and CPU when they were needed to run to calculate updated positioning. the reason to switch them was power dissipation, the unit was size limited, and with upwards of 2000 TTL SSI and MSI packages packed solidly on boards, double sided layout on 0.1inch spacing. The boards basically were really thick ceramic tiles, and IC removal was classed as extremely unlikely to succeed, as you had to dremel off the IC from the leads, take the new one and thin the case down slightly underneath, and then solder the leadframe to the remains of the original one. There were a few ones that always failed, 5474 flip flops, that were used for data and clock recovery on digital lines, and they got funky with time. The boards with all ceramic chip on were over 2kg for a board a little bigger than your hand. This drew a pretty impressive amount of power, the test bench had some large HP programmable power supplies that could provide 50A on the 28V rail to run them. Turn off the fans on the bench and you would have the case over 100C in a minute, with the fans on you kept pies hot on them.

author: CJay
author_rank: Super Contributor
timestamp: November 28, 2018, 07:49:51 pm
content: Nyaaaarghhh I remember those. And the G6, G8 and G11.

author: rsjsouza
author_rank: Super Contributor
timestamp: November 28, 2018, 08:40:16 pm
content: If you consider a CRT TV flyback converter as a SMPS, then the first was a 1980's Sharp TV my dad fixed in 1985 (or whereabouts)At around the same time I disassembled my grandma's late 1960's Philips TV set with vacuum tube flyback converter (PL36, PY88 and DY87).Protecting grids? Pffft! The high voltage rectifier anode was an aluminium hat on the DY87 near the edge of the PCB.I still have these tubes in my stash.

author: aargee
author_rank: Frequent Contributor
timestamp: November 29, 2018, 12:34:42 am
content: 3kV, 1A power supply (for a 27MHz RF generator) in an inductively coupled spectrometer. It used a H type bridge driver that fed 10-12 transformer modules in series to achieve the 3kV.Shortly after that an Apple ][+

author: shakalnokturn
author_rank: Super Contributor
timestamp: November 30, 2018, 02:49:46 pm
content: Quote from: CJay on November 28, 2018, 12:14:33 pmInteresting model I'd never heard of that one, by then I was in France, not sure many UK TV's got exported to France in those days.I remember working on a (Nokia IIRC) chassis with a single power/LOP transformer it was infamous for it's thick film hybrid module controlling the SMPS, Grundig also made a model (better design than the Nokia) with a single power/LOPT.Didn't know either of the Atari ST with external power...I'd sure count a LOPT flyback as SMPS, wouldn't count spark gaps, vacuum tubes or vibrators as solid state though.

author: CJay
author_rank: Super Contributor
timestamp: November 30, 2018, 03:59:52 pm
content: Quote from: shakalnokturn on November 30, 2018, 02:49:46 pmNot many did, PAL vs SECAM...Might the 'Nokia' have been a Salora/Luxor set, with the IPSALO PSU, that had a thick film AFAIR.Grundig had the venerable TDA4600 and TDA4601 SMPSU controller ICs, the PSUs could be really 'delicate' though, they went bang if anything drifted out of tolerance.

author: shakalnokturn
author_rank: Super Contributor
timestamp: November 30, 2018, 04:46:04 pm
content: You're right CJay:Salora/Luxor/Hitachi IPSALO stuff, the thick film (LF0059 I still have one hanging around) bears a Nokia logo on the back, that may be why I'm confused, I wouldn't swear I've seen it in a Nokia banded TV...

author: chris_leyson
author_rank: Super Contributor
timestamp: November 30, 2018, 05:04:57 pm
content: Not sure if inverters count as SMPS, the HT inverter in a PYE Cambridge that was used to power the output tubes 2 x QQV03-10.

author: spec
author_rank: Frequent Contributor
timestamp: November 30, 2018, 07:25:26 pm
content: In the 1960s we didn't have the cash to eat regularly and everything was expensive. Our TV was an eleven-year-old, 14" goldfish bowl Bush, in a beautiful veneered cabinet, the car was an ancient wreck, and all electronic parts were pulled from scrap equipment, mainly TVs.Unlike, in 2018, car radios were only for the well-off, and in any case, they were valve with noisy, unreliable, mechanical inverters, or low voltage valves with no inverter and possibly a solid state output stage. The latest all-transistor car radios were way beyond the reach of the poor and, anyway, in those days, they didn't seem to have the performance of the traditional valve car radios, RF performance being all important to get Radio Luxembourg and AFN.There was though, a few valve car radios with solid state inverters in place of the mechanical inverters and, as these inverters were dreadfully unreliable, there was a load of these faulty radios available for a song. Thus, my first carnal knowledge of solid-state switching PSUs was with car radio inverters around 1966.IIRC, there were two types of solid-state inverter: single transistor fly-back, and two transistor Royer. After having no success with the single transistor type, I focused on the two transistor type, which were much more reliable and predictable.To short a long story, after about a year of experiments and a mountain of blown OC28 and OC36 PNP germanium power transistors, I eventually fathomed the workings of the Royer oscillator and managed to get a set working reliably, but for some reason, after all the effort, the set never did get installed in the car.

author: bd139
author_rank: Super Contributor
timestamp: November 30, 2018, 07:45:15 pm
content: I’ve actually just snagged a whole load of Mullard pot cores off eBay to try and make a Royer converter. Hope I have more luck

author: spec
author_rank: Frequent Contributor
timestamp: November 30, 2018, 08:00:02 pm
content: Quote from: bd139 on November 30, 2018, 07:45:15 pmRoyer inverters are great fun and are quite easy to do these days, providing you know their critical areas. The big thing is to avoid early core saturation and transistor overlap, where both transistors are conducting at the same time. This kills the transistors and greatly stresses the core, and was the great mystery in my early days before I got the theory of Royer inverters.With modern chips cheaply available my advice would be to use an oscillator (555) and gate driver chip with dead time control.You would then have a much more flexible design with a performance that would beat a Royer inverter by a mile.Be a very good subject for a new thread on the forum. I'm sure it would attract a lot of interest and comments.In any case, good luck with your Royer experiments and let us know how they go.

author: bd139
author_rank: Super Contributor
timestamp: November 30, 2018, 08:15:45 pm
content: Thanks for the tips. Much appreciated. I’ll create another thread when I get to play with them. My intention is developing CRT bias and dual rails for a home brew scope with it ultimately but I’ll probably get bored by then

author: spec
author_rank: Frequent Contributor
timestamp: November 30, 2018, 08:35:53 pm
content: Ha Ha Ha- my pleasure.Following on from the car radio inverter experiments, I had a twenty-year on-going development program of designing and building scopes. The first scope used a CV138 ex military radar tube and mains transformer and valves from TVs.But after that I moved to a lab next door to the SE Labs scope development department at work. I immediately got friendly with the engineers and they let me have a load of parts, including a four-inch round, flat face tube with high sensitivity x and y plates, complete with mumetal screen. That was the basis of my next scope which ran off 12V and used a Royer inverter for the EHT, HT, tube heater, +-100V and +-15V supply lines.Then they let me have a 5" x 4.5" flat face graticule tube, which was the basis of the next scope. But I never finished that.Then they let me have a practically complete pre production SM111 scope, less the cosmetic bits, like case covers and engraved front panel.None of my home-brew scopes were totally complete, so finally I bought a faulty Gould OS100A for £5, and then a succession of other scopes. When we moved house a lot of my stuff went down the tip. Now I just have a Tek 2235A.

author: bd139
author_rank: Super Contributor
timestamp: November 30, 2018, 09:10:59 pm
content: Excellent stuff. I've got a VCR139A tube sitting here waiting. It'll be a very basic scope but hopefully enough scope to tick the bucket list boxMy father had an SE Labs scope for a couple of years. He really loved that but it was a leased one so had to give it back. I'd have killed for (and probably would today) for access to parts like that.Collecting scopes here, perhaps unfortunately. Got 4 Tektronix and 2 Telequipment units floating around.

author: BrianHG
author_rank: Super Contributor
timestamp: November 30, 2018, 09:17:14 pm
content: My Amiga 1000 power supply. BTW, I just loved the quiet smooth deep sound of that true 120v AC fan with the heavy bearings instead of today's dinky 12v DC fans. Also, the supply had very little to almost no leakage current to the mains. Nicely filtered, or maybe a really small X cap value.

author: spec
author_rank: Frequent Contributor
timestamp: November 30, 2018, 09:40:35 pm
content: Quote from: bd139 on November 30, 2018, 09:10:59 pmWhat a great shame; six years ago I could have sent you a really nice Xmas present as you live in the UK.The biggest problem with a tube like the VCR139A is the low X, and to a degree, Y sensitivity. You can provide the volts, but it is a job to get much bandwidth. Modern components will help a lot though.

author: spec
author_rank: Frequent Contributor
timestamp: November 30, 2018, 10:23:27 pm
content: Quote from: bd139 on November 30, 2018, 09:10:59 pmYou know, your best bet is to get a faulty production scope. Very often the PSUs fail and render the scope uneconomical for a pro repair but, presumably your time is free, and the repair should not be too difficult.Perhaps get in contact with one of the second-hand test equipment dealers or watch out for ads on ebay etc. Go or a basic scope though, or you may get stuck for specialist parts and difficult fault finding. One of the basic SEL scopes, for example, would be ideal.