Hi, it's tear down Tuesday Time again, quite a few people have been asking for this one for quite some time. So Eventually got around to doing it. It's the JC Car MP 3090 40 amp 15v bench power supply. Um, it's it's also uh, rebadged as the BK Precision 1692 and under a whole different one hung low names on the market.

so um, you can pick them pick it up pretty much anywhere. It's not a cheap power Supply it's about 340 bucks Australian and us. so I think if you get the BK precision one. but it's main claim to fame.

40 volts uh, 40 amps sorry output at 3 to 15 volts variable only a single term part. not that exciting voltage in current displays, there's no current limiting. Um, it does have the capability to have a fixed 13.8 volt output for ham radio gear and stuff like that. but yeah, onoff switch adjustable voltage and that's it.

but huge current and the thing only weighs about 3 and 1/2 or 4 kilos top. So um, for all that uh uh, current and power you If it was a linear supply of course it would weigh a ton, but this one's not. It's switch mode so let's crack it open see what's inside because well, it's just a high current switch mode. Power supply could be interesting, it could be boring as bad.

we'll find out. and of course it specs aren't going to set the world on fire. 10 million Vols output noise like over 200 MTS load regulation things like that, but it does have that 40 amps if it does do 40 amps at 15 volts I'm not entirely. uh, sure if it does over the full range like that, but certainly uh.

40 volts at lower uh voltages. we're talking. you know 600 odd Watts capability from this thing. It's not bad at all.

but yeah, I know PC power supplies do that sort of thing. but um, this one I Expect to be a bit better built than your average um, you know PC power supply but only one way to find out. Take it apart. All right.

what do we expect inside this thing? Well, as is typical with PC power supplies and most uh, power supplies in general, really, they're uh, pretty much going to use a single sided PCB So I expect expect a big single-sided uh PC switch mode PCB with some uh, heat sinks on it all through whole construction of course. couple of front uh, front panel boards for the display and stuff like that. So let's check it out. Oh what do we got here? wa yep there we go.

Bingo and the first thing you notice is it looks well built and well constructed. for us a typical uh, single-sided switch mode power supply I Like it. but what? I Found down here in this little section down here is the manufacturer and the manufacturer's model number H And there it is Manson Uh, 4520 doesn't seem to mean much but uh, if you Google Manson 8400 you also get the Manson Uh, 9400 and I was able to pull up a full service manual for it, you little Ripper So I hadn't heard of Manson before, but it turns out they're a Hong Kong uh based P company who specialize in power supplies so it looks like um, this is a reasonably, uh, well-designed it's not a slap together bit of Kit And in the service manual, not only Uh has it got instructions for how to, uh, calibrate and test it, it's got a complete component overlay, matching bill of materials, and most importantly, the schematic. Awesome! So inside this thing, the basic operation.

Uh, we'll look at all the individual components in more detail in a sec. but uh, let's uh, the basic flow here is Mains Input here. We've got some filter in here. We've got it going over to the Uh front panel.

Main switch here. comes in here. We've got some more filtering there. by the looks of it, we've got a bridge rectifier under there and uh, got a couple of more caps.

and then we've got a couple of uh Transformers which couple over into the low voltage circuitry over here. and then we've got our main Uh switch in Transformer Here We've got a big inductor up here. you can tell cuz it's only got the two wires coming out of it. Another big fat inductor here, couple of diodes on this heat sink for the output um, and some output filtering.

and Bob's your uncle. So let's take a look at each section in a bit more detail. and here's our IAC Mains input here. There is no Uh voltage switching.

It's Uh 240 specifically designed for 240 volts. We've got a Mauve here. It's actually heat shrunk in a bit of uh heat shrinking. Excellent.

Right on the terminals, exactly where it should be. This interestingly goes into a little board holding nothing more than uh, an 1 microfarad input uh filter cap. Once again, it's got all the necessary uh ul and all the markings on them. Check them out, there's a million of them.

and there's a bleeder resistor in there. tiny little one in parallel and that uses a connector. It's actually glued down. You may not be able to, uh, see that in detail there, but it.

but it is actually uh, stuck in place. It's excellent. We've got heat shrink uh, heat shrink over the terminals heat shrink tubing. We've got heat shrink Tu tubing over the um, uh, Earth uh terminal here in the Earth terminal goes down to a Um Shake proof washer down on the shazzy down there.

Excellent. and then it again, interestingly goes into a filter can here and we'll take a look at the circuit. for that. That'll just be a pretty standard Mains common mode Uh filter and the output from that.

Of course, they've got Um Earth coming out as well separately on the output side. Once again, heat shrunk cable tied brilliant and the output from the filter. once again, it's heat shrunk all the way over that goes into your double pole. uh, main switch on the front panel, it's got a real clunking main switch.

Um, once again, properly heat shrunk cable tied going over to some uh PCB uh Spade terminals over here. Once again, Heat shrunk. Beautiful. And here we've got an NTC the more filter in here.

another huge Uh filter cap. Once again, they really haven't skimped on the components. We've got a common mode uh filter here going over into the bridge rectifier and there's the bridge rectifier. They put a little Heat heat sink on top I Love it.

Little tiny plate. They obviously decided that they needed a just a little bit more thermal dissipation there. I Love it. Uh, 3.3 microfarad high voltage caps 400 volts.

haven't skimped at all now I Was wondering what this Transformer here is and and this, uh, little bit of circuitry here. until I Checked the Uh chip against the schematic and I found out that this is a power factor correction. it uh uses an MC Motorola um MC 34262 power Factor correction device and that's uh, part of the Transformer and the circuitry used for that power factor correction. So they've gone to the effort to actually do that I think that's brilliant and uh, check out the copper strapping shield on there and it's around the Transformer and they've got those on the other Transformers inside as well.

Nice attention into detail. They've gone to town to ensure that this design is actually uh, going to meet EMC requirements and uh, things like that. Now let's actually take a look at the schematic and follow the circuit up until up until this point because I don't want to get carried away and then show you the circuit later. So we'll do it.

Uh, step by step I guess and there it is Manson Engineering Industrial Co Dates from 2002 Rev 1.6 Now this is for the Uh 9400 model, but apparently the 8400 model that I've got here, well, presumably is exactly uh the same. But even the Uh 9400 uh model uh. the service manual shows it's branded 8400 on the Um on the overlay diagram. There, it is there.

so go figure like 8,400 and that matches that number matches my PCB precisely. But anyway, here's our input here. Here's our Mauve. There's our parallel bleeder resistor.

You remember the that cap and that resistor were on the board. The M was on the IC input connector. Um, uh, there's another NTC there. And there's the Uh inside the Uh filter.

that filter can, which we saw inside the unit there. And that brings us to our Main's power switch on the front panel. There, it is there. Uh, once again, another bleeder resistor, two inductors.

uh, a Main's rated filter cap. There's our common mode uh, choke there, another filter cap and there's our fullwave Bridge rectifier that we saw that had the heat sink on it. And that brings us on to our MC 34262 Power Factor Correction circuit we saw and there's the uh, big Transformer we saw there. it's a little eight pin, uh dip chip and all that does power factor correction.

and then it goes uh through this diode here into the main filter caps and as we saw in the previous, uh Xantrex uh, tear down, uh, video. We also these are series uh caps like this once again with the voltage sharing resistors across there. So we get our high voltage DC across here and here. which actually goes down to if you follow those wires down in there, it goes down to our main switching Transformer down in here, which we'll take a look at.

but of course we need a little power supply here to power the circuitry on our main board and that's what Tr2 this Transformer here does that. Uh, just Powers VCC There it is there through, uh, some filtering, small rectification, uh, filtering, and an inductor and another filter cap that's a VCC for our circuit. So if we take a look at our board, we'll be able to find Tr2 and that will be Bridging the high voltage part of the circuit with the low voltage part of the circuit and that's pretty easy to find. There it is There cuz you see this black line going through here.

They've got this black line on the silk screen which actually separates the high voltage and the low voltage uh part of the board and it's got a high voltage. uh warning. not sure if you can read but but there it is. high voltage section.

So all the stuff in here is uh, no touchy really. and you can't see the black line but it goes in between there and there's our there's some switching transistors in there but that is there. It is Tr2 and separates. uh see.

Uh, the one side here is on the high voltage section and the other side is on the low voltage section and there's another Transformer which does a similar thing here. Bridges High Voltage side with the low voltage side and that Transformer I just showed you is Tr3 here and uh, that actually comes that is actually the driver for the Uh Pwm controller and it's a Texas Instruments Teal 494 Pwm controller I see and that drives the two switchin mosfets here q12 and Q13 here to uh Drive the main Transformer which then gives us our DC Vol our main uh, you know, 40 amp Dc volts out and if we take a look at the Tl494 pulsewidth modulator control chip just very quickly. Um, it is actually a Pwm controller. fairly.

uh, generic one. It's not actually a switch mode, uh voltage regulator controller. As such, It's uh, you can use it for quite a few things, but it is Uh. One of its primary uses is Uh for a switch mode power supply application.

and if we go down here and take a look at the Uh functional block diagram here, you can see that there's not much in there at all. There's a voltage uh reference down here, an internal reference. There's a couple of error amplifiers that are some there. There's an internal oscillator, switching oscillator, There's a deadband Uh controller, and there's a Um, steering flip-flop and um, and some output uh, un some uncommitted um output transistors.

so you could use them in various configurations if you needed to. So there's really, uh, not much in there at all. So it is fairly uh, generic and uh, you would have to look at the Uh greater operation in terms of the actual schematic for this device to uh see how it's better used and there's a a typical application circuit and as you can see, they don't um tell you what the outputs uh go to because you can have your own Uh configurations and use them in various configurations and as you can see, it changes its pulse width um to actually uh match the various waveforms dependent upon the Uh threshold voltage and the feedback on couple of pins. there there it is DTC and feedback and that's pretty much uh uh all there is to it.

So if you wanted to go through it, you would have to uh, have a look at the main Uh power supply schematic and see how it integrates with this pulsewidth modulator controller and the Uh driver Transformer and things like that. well worth looking into. So q12 and Q13 there they're our Drivin uh mosfets and they're on a big Uh heat syn in there which I'll show you in a second. and as I said, it comes from the high voltage DC section up here.

so here and ground. of course it looks like there's a second, but there's a second wire coming from the center tap of these caps here and interestingly that goes through is AC coupled here through to the other side of the Transformer. Like that so it's switching between the positive rail here and the negative Rail and the center tap uh on the for this side of the Uh of the winding on the Transformer and the other side of the winding on the Transformer is connected AC coupled through to the center tap of those two Uh main uh DC filter caps. So this here TR4 it's the biggest uh, it's the big Transformer so it'll be the biggest uh Transformer in this box and we'll find it in a second and it's what transfers all of our power across these other Transformers we saw like the driver Transformer here is only H small fry.

it's only Uh transferring control signals and and the other one we saw up here um is only doing um sort of. you know, low current stuff to power the low voltage circuitry. but this is the big beast where all the power gets transferred and then we get rectified over here filtered and it goes through to our output which we'll take a look at. But let's try and find these uh big Power devices on the board.

We got a bit of Chinglish Happening Here Caution Warning: Will Robinson touching may hurt you by high voltage Exclamation mark. This one may be a bit hard to see, but there's the two switching mosfets uh Q12 and Q13 down in there on their own heat sink. So I've actually got three heat sinks in this thing. Here's q12 and Q13 the driving uh mosfets down in here.

That's that, uh, the smallest uh heat sink in the bunch. This big thing here as we'll take a look at as the output uh, output rectifier dodes and then this one up here is the Uh mosfets for the power factor correction circuitry which we saw before with the power factor correction uh Transformer and the controller chip hidden in behind there and you can see those side on output uh, rectifier diodes uh Drive transistor mosfets and power factor correction mosfets and I don't think I actually showed those before. There's the Uh Two, Q1 and Q2 the power factor correction mosfets there and I stand corrected. There is a fourth Uh heat sink in here which is uh, the diode D2 here because it uh, does uh, transfer effectively.

uh, all of the current through it for the entire Supply So that is inside here somewhere? Where is it there? It is. Tiny little puppy down in there and I just thought I'd mention the Uh fan driver. Yes, it is temperature controlled and there's the Lm324 uh, control circuitry should drive that. And as part of the Pwm circuitry, they got some dedicated over voltage protection as well.

that's just to stop the output voltage going berserk. If there's any Uh component fire inside this thing. and I almost forgot to point out our steamed main switching. Transformer There it is.

It's the biggest Transformer in the thing. Here's the Uh switching mosfets on there: heat sink down in here and uh, that drives the output as you can see fairly thin wires uh going in Rel relative to the high current output. huge big thick red and black ones there going into the output diodes and uh, these two inductors which we'll take a closer look at. So how does our output? uh, rectification and filtering works well.

It's pretty basic and you'll no doubt recognize this. There's a few extra components in there, but the basic Uh topology is a Um Center tapped uh, fullwave rectifier output. Here's the center tap which goes through the ground. just ignore all those resistors that actually goes through the grounded output.

The current sense: we'll get into those, but there's our Center tapped ground output and our two dodes here and here. But there's actually four of them. There's actually two in parallel there, and two in parallel down here. And of course, they're carrying the full 40 amp output current.

so they need to be heat heat synced and we've had a look at them. but we'll take another, uh, closer look. They've got some Uh caps across those. We've got an output filter inductor here, an output capacitor, another output filter inductor.

and once again, these two inductors need uh, carrying the full 40 amp, uh, output current. So they need to be big beasties and they'll stand out like dogs balls on the PCB Well, you've probably already seen them there, and we've got our output filter in here, some caps in parallel, and we've uh, got 12 uh, 0.1 ohm resist is All In Parallel here. It looks a bit weird, but they actually flip this up to here and that one's in parallel with that one that's in parallel with that Etc So there's actually 12 total uh .1 ohm resistors in parallel and that's current sense, which is actually uh, tapped off. Um, tapped off here and goes up to our current meter here and off to some of the circuitry over there.

and we've got some extra caps in parallel here. They'll be on the a separate output connector and they go to Shazzy Earth ground. You'll note the Uh Earth the shazzy ground symbol as opposed to Circuit ground. Shazzy ground and circuit ground aren't necessarily the same thing and that will be for uh, extra RFI compliance and filtering and the main output filtering.

They're not skimping here. They got two uh, th000 microfarads in parallel and different values uh here once again for filtering the different frequencies. These will have different ESR at different frequencies and we've got a 1kv cap here and a 330 ohm 1 watt bleeder resistor. So when you switch this thing off, it, uh, drains the voltage or bleeds the voltage off the output filter caps very quickly.

It's a nice touch and it's things like that which separate the uh, cheapy supplies from the good ones. So here's our main Uh switching Transformer up here and you'll see the huge, big, thick, heavy, red, red and black wires coming out of here solded on to the main board down in here. And here's our two Uh Bridge rectifier diodes in here. and here's that big um output inductor which you saw before, but where's the other output inductor right here you ask? Well, it's this sucker over here.

look at the Beast and once again it's uh, strapped for shielding as well. Beautiful and once again Hu because it's got to carry the 40 amps. Huge, big, thick C in once again heat shrunk. Done it very professionally.

I Love it. Now this here may look a bit bodgy these terminations, but they're not. That's uh, reasonably common. There'll be like a little uh Spade terminal under there, uh mounted on onto the board, which then they solded directly onto the top so it looks bodgy and Blobby but it's not that bad at all.

And here's our output current sense resistors here, which uh allows us to read the output current. And if you're wondering what these big metal things are, they're huge, big um, uh jumper links effectively. That's uh, what they are cuz they can't rely on just the PCB to Uh transfer all of the huge current from this side all the way over to our output wire in here. they use these big thick uh metal shunts to transfer all the current so it doesn't have to flow through the copper on the board.

Other small touches in here: this capacitor is actually glued down as a all the other main capacitors in here. and the same can be said for some of the Uh inductors here, the common mode chokes and these caps. They're actually gunked or glued down as well to stop uh, vibration, um, uh, during Uh transport and use for uh, these things actually shaking loose and breaking off. Nice touch.

They've put you know a lot of effort into actually designing this thing properly. not just uh, designing the circuitry, but actually the physical build as well which will, which is what will set a good quality. Supply Apart from a lowquality one which you know this one might last 10 years and another one hung low brand will be dead after a year on a trolley being wheed around in a production environment or something like that. Another small attention to detail: The Uh main, uh, inductor output inductor here is actually got these metal plates to hold it down as so as the main.

Transformer They haven't relied on just the Uh Transformer itself. they've gone to the effort to put a plate there, the Bol and bolt through, and a shake proof washer on the underside of the housing. and there's our 40 amp output wiring going over to Huge. You're probably going to have to might have to get a different angle on this one, but goes over to the big Uh Spade terminals mounted on the front panel.

I've had to go handheld for this one, but you can see the huge big 40 amp red wire there going into the big crimp terminal. onto the big Uh nut and washer there on the front panel and they're the two. You can see the black one as well. They're the two front panel output Terminals and you should be able to just see those two disc ceramic caps under that Uh heat sink.

There, they're on the Uh, they're the filtering on directly on the front panel PCB that they've actually got a small PCB there that uh, mounts those two output uh, binding post and uh, terminal lugs. And really, there's not much else doing. On the front panel, there's the uh, single turn voltage, uh pot on the front panel. it's got its own board, our output display, voltage and current display with its own regulator there.

Once again, it's glued down to the top board there. that's a little bit bodgy. it's at a different angle I think uh, they they kind of, uh, maybe didn't have enough room left over. It sort of seems to be wedged in there like that.

uh, but apart from that, uh, there's not much else doing on the front panel. There's another tiny little board over here for the LED indicator on the front panel. but that's about it. But there is one thing left on the front panel and you'll see that high voltage cap there connecting the Uh circuit uh, common output through to the shazzy ground.

And as far as the main PCB goes, you got a couple of uh single turn trimmer caps in there there for uh, tweaking this thing and you'll notice that there's a switch here switch to which actually is uh, inverted and it goes through to the switch on the back panel which is the uh, selectable uh 13.8 volt fixed output and it's warning you at the 13.8 volt is selected, the front panel voltage control is disabled. well, Du, of course you'd expect that. But warning So overall, what have we got here? Well, we've got our 240 Vol Mains input here, some filtering fullwave Bridge rectification Here we've got our power factor correction magic happening here. We've got our main high voltage filtering that uh branches off into over to here which uh Powers uh via a isolation Transformer power some low voltage um uh circuitry like all of the low voltage circuitry basically and it branches off down into here like well this here we go and it also Taps off down into here into the main uh conversion Transformer here which is controlled by this uh driver transforma here which is controlled by this pulsewidth modulation uh controller which actually uh controls um, the output voltage of this Transformer And then we've got our uh full wve output uh Bridge rectifier Here we've got some Well, we've got uh, some uh filtering there with the inductors and then we've got our main output filtering going off to our output terminals over here and that's pretty much all there is to it.

There's some reference type circuit stuff up here and over voltage protection and fan control and and some other stuff happening around there, but that's the basic concept of it. Check out that squiggle. It's got to mean something surely. H So there you go.

There's the Powertech Jcar, Mp390 or BK Precision 1692 or whatever brand or it's actually manufactured by Uh Manson in Hong Kong it's the Um SPS uh 8400 9400 uh 40 amp, 3 to 15 volt switch mode power supply and it's really wellb built. I Was thoroughly impressed with that I Couldn't really fault the thing. It's got everything you would want in a switch mode power supply. Lot of attention to detail.

very well built I Love it. Highly recommend this thing. Uh, but it's on the pricey side. You know, as I said, it's well over the $300 Mark Maybe you can pick it up, uh, cheaper than that, uh on the street.

but yeah, it's built really well, really well designed and I'll have the uh service manual with the schematic um and the parts list and everything else. uh Linked In the video there. so I highly recommend. uh, checking that out and uh, also those uh data sheets as well.

So for the main controllers cuz these are fascinating things how they work so it's uh, definitely worth some bedtime reading there. So there you go that's tear down. Tuesday If you like it, please give the video a big thumbs up on YouTube because it really helps a lot and uh, you can as always, you can discuss this in the E blog. Forum Catch you next time! Um,.