Random Bunker dumpster item teardown. A 20 year old Australian designed and made electric fence controller.
Repair guides are here: https://pakton.com.au/support.php
Forum: https://www.eevblog.com/forum/blog/eevblog-1277-electric-fence-controller-teardown/
#Teardown
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Hi. check this one out. It's a random teardown item from the bunker and it's Electric Fence Controller. It's the MBT 200.

Look at these gigantic screw terminals on here and it's actually an Australian unit. Check it out. Manufactured by Packed In Technologies, they are still around and this is what they do. They manufacture electric fence controllers, so I've contacted them to see if I can get a U schematic I'll see if it turns up in time both time I've finished this video Anyway, it's a really old model that I can't find any info on at all.

It's the MBT 200 type of D whatever that is. input 16 volts AC or 12 volts DC output into 100 ohm load 12 joules so doesn't tell you how many kilovolts it does, but it's got to kill a volt display on it AC and DC inputs and a switch and that's about it. and well. I don't know anything about electric fence controllers, so let's crack it open and see what's inside.

Lots of big caps, no doubt. All right. Six screws on here and that trainee Wow that's enormous. Look at those caps.

Oh yeah, that's where all the jewels are being stored. Oh look at this - troll. Yeah, you Bloody Rippa. Unbelievable.

What's that? 30 Mike please II do con caps 30 Mike 900 volts DC each Wow. Pulse grade capacitor made in Australia Ah Bloody Beauty yeah Lizzie I used to work at GC Marconi yet they were plays I think GC Marconi Bought out pleasure and now the GC Marconi technology park at Meadowbank is now just as only a few buildings left and there's a road called Faraday Road left and that's it. And it's all like housing developer apartment development complexes. Now it's really quite sad.

Anyway, that was a they had their own ceramic hybrid manufacturing facility and everything anyway. I Don't think they made that. they didn't make the caps there I'm not sure where they made, but somewhere in Australia Oh Check it out. that's a size that transformer in there Wow And here's all the output caps: Wow Check that out! I've got a separate riser board for that.

So I got a bunch of big power resistors and yes, I can poke around. It's been turned off forever. It's just been sitting in the bunker so I'm sure it's completely discharged. They'd be amazing caps if they weren't so I would assume they'd be in series I would yes to get the to get the voltage requirement I'm not sure how many kilovolts this suckers gonna be, but Oh Anyway, there we go.

There's different models. This is the MBT 200. so NBT 50 and Bt 50 and Bt 80. maybe I can get some info on the BTS so that's actually 2004 vintage down there.

and if you go to the website which are linking down below, they've actually got some amazing repair guides for these things like a PDF with all the instructions on how to troubleshoot and repair these things. Unfortunately, they don't have this particular model and they don't have a schematic in the ones that I saw. But yeah, it really is quite nice. So I really so do seem to support these.
And they do actually have an eBay store where they sell replacement capacitors the same xxx Mike nine hundred volts but not the pleasant ones anymore cuz I'm pretty sure you can't They're not making these anymore in Strayer and you can't buy them, but exactly the same rating from Hong Kong or HK Capacitor I Assume it's Hong Kong capacitor. They manufacture a range of these same ones so they still sell replacement caps in these things. So anyway, yeah these are these are fantastic. Job is they'll be flame proof and they'll be.

You know they're designed for like high pulses because Electric fence controllers I believe although there's many different types, is lethal, non-lethal and there's ones that go that go from like giving you a warning zap to ones that then on the second zap will kill you. You know they're designed for like you know, prisons and military installations and stuff like that. But yeah, this is probably just an agricultural model. So you know to stop animals getting through electric fences on the farm.

so it's probably not lethal, but you wouldn't wanna touch it. Um, you know, 12 joules? Oh geez, you'll know you're alive if you get hit with that. Let's that's for sure. So it looks like a pretty dumb unit.

There's no smarts in here. um I'd say that the killer volt meter is just like a panel meter type thing because I don't see any micro controller unless you know something's on the other side. Maybe we can take the board out and flip it over, but I wouldn't expect anything on the other side. I think we've just got a primary side our storage and switching here.

so we've got three big probably MOSFETs in there and that switches this huge big custom transformer here and to the secondary has got any feedback. I would say that this big resistor here oh that's my D Oh - what's in there? Whoa. What is that? It's got a cover on it. Oh there's two leads on each side.

Oh Oh Oh - it's an opto isn't It's an opto coupler is it? Anyway, these are usually are like post DC type things I'm sure there's many different US standards and and stuff like that for them, but yeah I believe it's like a post DC type thing so it doesn't give you like and continuous direct DC shock. it will actually pulse. That's why you need our pulse grade our capacitors, input and output - of course. But yeah, I'd say it's got some sort of feedback to regulate that.

And what's that resistor up there doing is that a bleed resistor is at a feedback job' If you have a little down in there it says HTF B that would be high tension feedback so that's either feeding back from the secondary side. B Given its location, it doesn't seem to be, so maybe there's like a intermediate step up there and then before it gets to the big trainee. perhaps? And that's what they mean. Well, there you go.

I Spoke too soon. there's your microcontroller down there. All the Pic fanboys go. Why one? is that a pick 16 if series? given the vintage of this sucker and that's just driving the LCD There is some extra surface mount chippies under there.
they're just. they would just be LCD drivers because the Pic wouldn't have direct LCD drivers and there's not enough pins anyway. So yeah, so it's probably a little Op-amp in there. Couldn't be bothered.

Check in. We've got some leads and no surprises for seeing big cutouts between the capacitors here. Although they don't extend all the way out here, I would have extended those out a bit further than that. That's a bit.

it's a bit tighter. Um, look, they've extended it out this side, but they haven't extended out that side. Is this an afterthought? They've got a mob on the straight-across that kept there. So yeah, maybe they don't come.

A guts are somehow in the design and they've added that as an afterthought because otherwise you'd put that directly on the PCB And then they got another switching on its back on the bottom side, which is unusual. Don't know why you wouldn't have, you know, laid that out on top sides or a layout issue really. But yep, all three of those caps are in parallel. so yeah, no touchy, you know, just check to see if the negative of these caps is ground referenced.

So yep, course it is. Now this is interesting. This that was the big power resistor we saw on the top, and sure enough, it's between the positive and the negative output like this. but it goes through that little opto sensory type things component across.

There is just a reverse biased diode that might just be a dropper resistor that doesn't actually have to be a load, otherwise it to be current sense in the load. So I'd say more likely it's just voltage sensing and that's just a dropper for whatever the heck part this is. Just wanted to show your fork a close up of these pleasu con caps cuz yeah, you rarely see those and you won't see them anymore cuz I'm pretty sure they don't make them. ha.

I Figured this out. It's obvious it is an opto coupler and there's nothing in the middle squishy, squishy that to lead and that's a photo trainee. so they just roll in their own optocoupler. they're just presumably they couldn't find one with enough withstanding voltage.

Fair enough, it's a cheap way to do it, so that right there is a one Meg LED Drop a resistive. You ever seen a one mega LED dropper as this stuff. Hands up. I'm sure there's not many of you, so if you do the calculation for that, of course, ignoring the little piddly diode drop Compared to a thousand volts, you know you just do rules of thumb in engineering, then that's one milliamp per kilovolt.

So a typical lead might be 20 milliamps max for example. Then you know zero to twenty kilovolts. That makes sense, doesn't mean it's gonna go out to twenty kilovolts I Don't think it does. I think these only go up to, you know, several kilovolts.
maybe five tops or something like that. Perhaps could go higher. But yeah, that makes sense. Just one milliamp per kilowatt? Easy.

So you would just get a proportional current in the phototransistor on the other side of that optocoupler. Roughly, if you power 20 aficionados. there you go. but the one on the left there, the friend of Jake the pig suddenly got two legs.

In fact, both of those other parts down in there there are diode ease I ain't So obviously we've got a first stage us which are here is our switching. There's our switching transformer and that would be generating. Well, these are nine hundred volt caps are all in parallel. so you know, be generating.

you know, seven, eight hundred volts. Something like that, you wouldn't be pushing it right to the 900 of course. and then that. then you'd use the this other switching over here to take the energy from these caps and drive your transformer to get switching again to a boost it to your high output voltage.

I Actually, rather like this our spade lug arrangement like this: PCB mount Spade lugs and they just go in like that. That's a neat way to do a vertical rise, a bore. But anyway, and there you go. We've got the positive and negative outputs and we've got a common as well.

and we've got to be I don't know that varies 56r and 100. Ah, there you go. But yep. I'm guessing all these cups are in series And yep, I am right? Yep, check it out.

There we go one there. Series Series Series Series series. So we got six cups in series. How many volts each? That'll tell us our maximum output.

So if you don't know the maximum output voltage of a design like this, you can just calculate it well. These are two hundred and fifty volts captain and 250 volts each. They wouldn't be running them at 250 volts. So at let's to say 206 times 200 1,200 volts.

So 12 times 200, that'd make our 2,400 volts with an absolute max our voltage rating of 3000 volts. So yeah, it's not gonna be over 3,000 This is good because I Have an old analog meter. Know now there's digital rubbish. Have an old analog meter that measures up to five kilovolt.

Self-repair This thing on I'll be able to measure that directly with my analog meter. Beauty. And in case you're wondering, those B power resistors. Here's the positive input coming from the transformer and it goes through a series resistor and then through the series caps like that.

So those caps are actually in series and then they are just half tap in the capacitance network here to give you your common. And some people might be wondering, well, why don't they put our slots in a board like this? Well, you can of course are to prevent creepage which is across your board. Or like this, if you get moisture contamination or something like that across your board, you can certainly do that. But because these are only 250 volts rate at each, Essentially, there's only 250 volts between there and there, and that's plenty of creepage clearance for 250 volts.
DC So when you're welcome all in series I you could argue like there's more across there and stuff like that. So you could argue they could should be maybe a slot down there or something like that. Yeah, it obviously does the job. Yeah.

I Think if you go, get your chart out and work out your clearances, it's it should be enough. And then there's three of those moles in series or six of them in series across the entire positive negative output. Again, because they didn't have the individual rate at once I Guess. And these two unpopulated components marked here? Yes, they would be spark gaps.

So yeah, they just haven't populated in the spark gap. So I've been guessing. You know they didn't want both the moths and the spark gap. So either/or so I do actually like this.

front terminal arrangement really is quite good in that vertical board with the Spade lugs and these go through the holes on the PCB Like that that is. That's really quite neat solution. All right, I'm gonna power this thing up I Have no idea if it works I don't It literally came from the dumpster. so I don't know what the deal is I'm gonna pair it with my micro supply.

and as I've said many times before, anything over 12 volts DC scares the out of me. So I'm not gonna be anywhere near this sucker. So let me move this away a bit further. So here we go.

Our 12 volts, one amp, turn it on and oh, it works. It works. There's digits as digits on there kilovolts load factor. Let's uh, there's a - - - let me I'm destroying fourteen milliamps that's quiescent current.

Obviously, learning dies out always. So that's a power on test I guess. So let's switch it on nothing. Maybe it was already on nothing.

Either way, you don't need a load on it, but I think and there's no Energizer light on there or anything. so not what what? what? wha? sorry. Decided to hook it up to my beefier lab supply here and 1.5 amp current limit. which my little micro supply can't do it.

and we do get a brief output here. What's this? overload? and then energizer? Okay, briefly, but nah, it's only. it's only rated for 1.1 amps. so maybe there's like some input pulse something like that I might leave at the hemp.

Was briefly thinking and charged up slowly, but like it's 10 milliamps. This is quiescent stuff. It's not. It's not in any energy.

there's no jewels gone in those gorgeous Ozzie caps. Alright, well, let's try it with a load. Got this in the previous mailbag. coincidentally I don't know.

It's a voltage rating and does have exposed terms turns there because it's an adjustable power resistor. but she'll be right. that's 1k. This thing's are rated for lower loads than that.
So anyway, um, let's give it a bill. Note: Exactly the same thing as before: I Don't know if you saw that the Energizer LED does briefly. come on, but that's it. I mean it's not going into overload or anything, just quiescent current.

So I've had a bit of a little quick poke around in here, but I can't see anything obvious. now. One of the things is the the switch on the side. here.

This is actually connected into a like a single inline header. there. is that the right one? I don't know. it is labeled T2, whatever the heck that means so.

but unfortunately, like without a manual and without a schematic and the flying a bit blind. sure I could you know start reverse engineering this or having an educated poke around? But the good thing is is that patent claim that they will supply the schematics. they actually tell you this on the website, end on the in the actual like troubleshooting documentation as well. So I have emailed them but like it's Christmas and New Year's time so probably like completely shut down.

so rather than spend my time actually you know doing this I'll wait until I come back and if you're watching this I am actually on walkabout somewhere I'm so I'm not in the lab so I won't be back until towards a late January So hopefully by then though, be back and they can send us a schematic and maybe maybe an operational manual for this things so he might get lucky and if they don't come through then we can always do a reverse engineering video. So if you want to see a reverse engineer of the circuit of this thing then mention it in the comments down below and give it a thumbs up. to the more thumbs up. I Get the attempted I will be to do a follow-up video for this one.

This was supposed to be just a teardown so I'll call it quits there and I won't attempt to repair this thing and/or if there's anything wrong with it. maybe it's just a you know, a peb kak I don't know how to use this thing. Maybe someone's fiddled around with it I don't know and it's got not for sale I written on the back of it. so I'm not sure if this is and given that I can't find any info on it.

Maybe it's a could even be like an unreleased or limited release product or or something like that. but it does have you know, prop, a, serial number and everything up there. So yeah, not sure what the deal is. but anyway, I'm packed and do claim to supply the schematics and this is, well, 16 years old.

Geez, you know, 2004 That was yesterday and what's 2020 Now by the time you're watching this? Geez. Anyway, yeah, so I feel like that turnout of this Ozzie designed and manufactured unit? Absolutely brilliant. Our pledge caps let us know in the comments down below if you've used pledge caps and when they actually stopped me I presume they stopped making them. Another thing, they make them anymore.

Please correct me if I'm wrong and this custom trainee up here is that meeting stronger too? Maybe. Anyway, Um, yeah. Ripa So anyway, they do have lots of more advanced models now, but yeah, if they come through the schematic then we can have a go if not or reverse engineer. maybe.
I Hope you enjoyed it. Catch you next time.

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By YTB

24 thoughts on “Eevblog #1277 – electric fence controller teardown”
  1. Avataaar/Circle Created with python_avatars Robin Sattahip says:

    Here in Thailand about once every 6 months or so you read about some idiot using straight 230vac with predictable results.

  2. Avataaar/Circle Created with python_avatars Spartaeus says:

    Terribly overcomplicated !!! Built just to make sure you keep buying more. There's so many simple fence chargers that have lasted 50 years plus. I wouldn't buy from that company.

  3. Avataaar/Circle Created with python_avatars matt dunlop says:

    How can you tell a electronics guy from an electrician? "anything over 12v scares me" hahahaha good one dave.

  4. Avataaar/Circle Created with python_avatars Rupert Price says:

    I worked on fence energizers 30 years ago and this topology was fairly common including the basic opto coupler . The New Zealanders were the masters of the electric fence energizer and everyone copied them . My biggest failures were my transformers which were a crude high reluctance design but because of poor winding practice which caused the secondary winding to go short circuit/breakdown.

  5. Avataaar/Circle Created with python_avatars Steve Tobias says:

    Reverse engineering, bloody oath mate

  6. Avataaar/Circle Created with python_avatars Will says:

    What ?, it's not fixed yet ?

  7. Avataaar/Circle Created with python_avatars Taran72 says:

    It's so interesting! thanks.

  8. Avataaar/Circle Created with python_avatars Nothing\ says:

    100 Joules seems like an awful lot. Although no body, human or cow will only have a 100 ohm resistance. Just off the top of my head, I know 200 joules is about what they use for cardioversion with defibrillators. Of course, that's directed right across the heart. So it's not quite the same. Still an interesting comparison to make though.

  9. Avataaar/Circle Created with python_avatars Trapper John says:

    I work with fence chargers for a living. While I've never used this specific one, I can make a few guesses based on what I know

    First off, the ground line is meant to be connected to literal earth ground and the other two to fence isolated from the ground. It should work with or without anything connected to it

    Secondly, these are usually designed to send out pulses every 1 or 1/2 second, and the current rating stamped on them is usually the average over time, so when you consider it's not drawing current most of the time, the actual peak amps is usually much higher than the label. I've seen them blow five amp fuses

    Third, most of the time when they say 12vdc they mean a 12v lead acid battery, which, as I'm sure you know, is actually a little higher than 12v. Most of the ones I've used have a built-in battery protection that cuts out or switch to slow pulse at 11.5, and I wouldn't be at all surprised if some of them actually cut off at 12. You should try giving it 12.5 or even 13 volts if you haven't already

    Lastly, if you're poking around in one of these, keep in mind that they're designed to deliver a painful shock through several miles of fence and earth, to animals with thick hides and hooves. It hurts a LOT more when you touch the wrong thing inside with a screwdriver. I have heard stories of them causing heart attacks

  10. Avataaar/Circle Created with python_avatars Paul Quigley says:

    I worked at Plessey late '80s early '90s. Worked in the hybrid facility. Was the big sonar test tank still there when you worked there? I also taught electronics for a short while at Meadowbank tech. There you go!

  11. Avataaar/Circle Created with python_avatars Fox Davion says:

    It's usually very hard to find info online about electronics predating the creation of wikipedia and also before the mid 2000s unless it's something historically important or still in use today.

    That thing has some very large electronics, when I see large electronics I instantly think it deals with rather high voltages.

  12. Avataaar/Circle Created with python_avatars uh says:

    Good on paul for the reply, …but… Reverse enginerd that thing! We need to see the embarrassing faults so we can learn from others mistakes… Thats the beauty of the internet, right? Helping to curve darwins theory to outside the bell

  13. Avataaar/Circle Created with python_avatars DELTEKKIE says:

    I used to spend summers on my uncle's farm when I was a teen in the USA back in the 1970s. Farmers around where he lived all had electric fencers similar to this to keep cows from getting out. Although they were much simpler design. They would output a pulse about around 20KV in about 2 second intervals. Yes! You knew when you got a jolt from that.

  14. Avataaar/Circle Created with python_avatars xXYannuschXx says:

    Jesus, that looks like something designed to jump start an elephants heart and not something that is meant to deliver a harmless shock!

  15. Avataaar/Circle Created with python_avatars G7MKS says:

    I remember being dared to pee on an electric fence wire, having played around with magneto phones I decided to be a yellow belly and decline.

  16. Avataaar/Circle Created with python_avatars Tom Jackson says:

    Yes! Please reverse engineer it!

  17. Avataaar/Circle Created with python_avatars TheChipmunk2008 says:

    Odd fact, my mother worked for Plessey here in Southern 'old dart' Not sure what she did, wasn't for long

  18. Avataaar/Circle Created with python_avatars Bong Jovi says:

    I've reached over an electric horse fence that was armpit-high and as soon as my armpits touched it, my arms came down over the other side of the fence and if my legs didn't give out, I'd probably have gotten a good frying. These things are fuckin powerful.

  19. Avataaar/Circle Created with python_avatars David Anderson says:

    I can't wait to see more of this.

  20. Avataaar/Circle Created with python_avatars George Mays says:

    Neat. I'd like to know how it works….

  21. Avataaar/Circle Created with python_avatars TSENZ says:

    I went for a job interview at Pakton, they were in Narangba QLD then.

  22. Avataaar/Circle Created with python_avatars George Ray says:

    INTERESTING x 2 ::: (a) your interrogation , (b) the feedback from the designer. ==>> REVERSE Engineer and have friendly dialog with the designer about the GB&U (Good , Bad & Ugly).

  23. Avataaar/Circle Created with python_avatars Richard Watt says:

    Dave, I don't know if you'll see this, but I used to work for Marconi Communications in the UK (until they went bust in 2000-ish).

  24. Avataaar/Circle Created with python_avatars EEVblog says:

    UPDATE: Pakton have responded and unfortunately don't want to release the schematic for the MBT200. They are actually a bit embarrassed by this old unit and think "the plastic case was horrible".
    They have offered a more modern JVA brand unit for a loan teardown and are happy to answer questions on operation etc.
    The designer (Paul) has chimed in with a few comments:
    "That unit was one of the first prototypes of that model, hence the "not for sale" on the back. I designed that unit. The PCB and firmware were all Pakton.
    JVA is our in house brand. Pakton is an OEM designer and manufacturer, we make and badge product for a lot of the other brands in the industry. 90% of what we make is exported, we are one of the larger manufacturers in this niche in the world.
    It was a very reliable model. The output transformer is our most reliable by far. It was designed by myself in conjunction with an incredibly talented engineer in NZ called Bob Smith of Marque Magnetics, since deceased.

    One of the key new features in this energiser design (when it was released) was the moving of the filter capacitor (usually across the primary) to the output. I had a patent on that. This improved the pulse shape without increasing I^2R losses in the primary, it also allows the leakage inductance of the transformer to work with the filter capacitor (or more accurately it's reflection in the primary). The goal was to produce a soliton pulse shape when coupled to a real fence. We did a lot of testing on long fences in western Queensland. Real long fences are mostly capacitive in load. I.e. lots of reactive power flows. We have since patented methods of measuring the real versus reactive so we can isolate faults. Some of our monitors can pin point a fence fault to within 1/1000 on the fence. See the ZM20.

    The move in electric fencing now is all towards monitoring, farmers do not have time to test their fences, and it's critically important to know if there is a fault on an electric fence if it is being relied on to keep stock in or bad guys out."

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