Hi Dumpster-diving time again. Check this out! It's the first time ever that I have scored a touchscreen all-in-one PC and this is a HP Envy 23 Touch Smart complete with Beats Audio Wank Wank wank and it's got a Core I5 in it dates from March 2012. that's the model number anyway and it's got a Core I5 3750 I think it is in it and yeah, somebody has dumped it. Um, now it did actually have the plastic unclipped like that.

So I'm not sure what the deal is. they're having a hard time back in, but unbelievable. why would someone if it does work I can't believe somebody would throw this out. Anyway, the model number is 23 - D double O 5 a it's got a tuner in it Wow it's got pain in the arse DC connector though.

and well. I've got like four or four lots of these and I found one that I think might fit. but I looked up the specs for it and it's a hundred and eighty watt power supply. It's 19 volts at nine and a half amps.

like nine and a half amps or one of these little Dickie a barrel jack type things with it. looks a reasonable NIC apart from the case being slightly off. Anyway, it's got a USB 3 and SD card reader and everything on the side. So anyway, um, we'll try and power this thing up and see what's what.

Okay, I just realized that it's not actually the pin in there that does it I didn't know this, but there's an inner barrel inside there. so okay. that would make more sense because if you just had the Dicky little pin then it wouldn't make any sense at all. anyway.

I do have a supply I forgot I Had this Beastie the Six, Six, four, two I I've got a couple of variants of this. This one actually conveniently does 0 to 20 volts. Tips: Perfect. A buzzed out.

the outer barrel on there goes to Mains Earth, so that's got to be negative. We'll plug it in and see what happens. Fingers crossed. All right.

Here we go on. Let's go for broke. One and a half amps, two amps. It's drawing something soft.

power button on the top. It's drawing one point. six amps. no magic smoke time.

it's doing something. at one point. six amps. Maybe the screens gone.

Maybe that's why they dumped it I Don't know. Yeah. thirty. Oh, that's enough to boot it.

Um, really. you know to boot a core I5 now I actually have a lid on the back that's on. sort of doing something. so maybe it.

maybe it's booted and the screen is busted I Don't know. might have to come apart and uh-huh There's a screw loose in the top paddock that's completely it. Someone's someone's out of play with that. so maybe they've tried to.

Yeah, yeah. a little warranty void stick out. someone's that. someone's at it.

Go have it go. your mug. Tada, we're like Flynn Oh look at that. That comes up beautifully.

Well, because Allah So there you go. I've never seen a inside one of these before. I haven't done a teardown on one of these. but look, we've got our 1s.

so DIMM modules down in there, fully populated. Thanks for playing And of course a ton of shielding on this thing. And there's your CPU there's your right laser he'd think of big copper pipes on it and a squirrel cage. a fan in there.

wonder how loud that puppy is. but so now. solder connect though. there's a hard drive.

a Somebody's okay, somebody's ripped the hard drive out of it. I Think that's where it's It looks like there's a cage which goes down in here. So yep, that's why they've ripped it apart. not necessarily to fix it, but to remove the hard drive before dumping some back.

I think So Yeah, Yeah, yeah, it's a backlight. Okay, now let's switch this puppy on. Today is actually a light down in there and now I'm fan has spun up. it's going.

Oh, say that the processor in this baby is working and it's likely booting at one point. Six five amps. So so much for the you know, the hundred and eighty five what keeper will power supply it needs I Didn't have to worry about that at all. Could've just used a regular rough lab bench supply to get this thing powered up.

Of course it could consume more if the screen. Maybe the screens like completely cactus and isn't drawing power. I Don't know, but the nominal power consumption of this thing is. Check out the Wi-Fi antennas up here.

You can see them there and there. Okay, the button is definitely work. Hey, it's illuminated. They've got some LEDs on top of the power switch there that's doing the business I Don't see them changing.

They're supposed to change color or whatnot, but check that out. Isn't that pornographic? Oh Legalized Copper heat pipes Beautiful. I Coming off the core I5 processor there and check it out under there in its own on its own daughter board. They didn't build it under the main motherboard because they can upgrade it.

That's the graphics card. It's a HD 75 something or other. Radian I carded I Believe it's you know, hugely powerful, but good enough around this sort of all-in-one purpose. And there's our webcam attachment there that's going up there.

so that's the, that's the NSA Edition Now what I'm looking for is some sort of external that you know LCD connector. Some sort of video connector that I can hook up to look at this DVI There it is. Can you see that as um, a DVI and the one above it says MX m DVI But yeah, I don't have. he's sort of adapted cable for anything like that.

if I did I could like use that to bypass the building screen just to make sure that the processor what it looks like down in the bottom of the case. Here we have like a secret squirrel a USB connector. It looks like you shove something up. Its clacker there which is different to the four.

USBs We got over here, which are you know, user-accessible on the back panel. The two USB three is here. so that's a special secret squirrel one that? what is it? You know, a service connector, upgrade, bias thing? whatever? I'm not entirely sure. Anyway, there's our tuner card.

Get the model number for those playing along at home. Okay, what I think I'm gonna do is nuke it from orbit. It's the only way to be sure and just remove the bias and short that out and clear that they I don't know if there's a switch or a jumper? Oh yeah, I think there is if I take that out. these are by the way if you're wondering.

These were for gig a pop. So this has got eight gig CMOS plus password. let's reset it, repair it, see if it makes a difference. Shouldn't though.

can't see how. Check this out. This is really groovy. I Don't think I've ever seen this before.

Look, it's a vertical watch crystal holder. Let's solder that in vertically and that's what they're doing. They're holding that up. That is remarkable.

Hats off to whoever did that that's gilding the lily. Okay, the next thing I just thought of is that may because these are like really ultra consumer II kind of. you know, user experience kind of thing. Maybe with no hard drive in here, they've removed the hard drive.

Maybe it just simply doesn't boot up with anything like no bias messages or anything like that. perhaps. So I've got a drive from another machine which has Windows 10 on it. Prop it up a bit.

No workers. Uh-huh that's the hard drive lid. Still nothing. Bhama I Figured this out.

This is the LVDS going off to the panel and MX M is actually the graphics card. That's why we got to the UM A1. I Believe that would be the integrated graphics inside the Intel core I5. So um, yeah, we can choose between that.

So they've got the LVDS one and they've got the DVI. It's a DVI Exactly the same here. so if we had the proper connector to convert that into a DVI connector, we could just hook on straight onto a D and external Monda not. anyway.

I'm gonna swap this over from the video card because who knows could be a video card at fault. I Actually rather like the thermal design on this, by the way. I'd not just you know for the copy heat pipes, that's You know it's common in laptops and stuff like that, but you know, like they've done it right. they've got the air coming out of the top, you know, like the squirrel cage fan I Can hardly hear that thing at all.

It's not much and it's you know. and then it just it pushes out and sucks it in from down here and then pushes out the top exactly as you'd expect it would. So that's nice design in case you're wondering. Nope.

I got diddly-squat with the LCD changed over to the UM A. So what? what? what? Wow Okay, the next thing I want to check is the other end of the flat flex cable? They're going into that. So I got to get in there and carefully unclip that and just have a little wiggle wiggle wiggle. Yeah.

Alright now I'm starting to think that it's the backlight LED backlight driver over here because turned off the lights, turn it on and there's no residual LED backlight at all. So that could explain it. Okay, so let's actually disconnect the board and take some readings here. I've got it connected through to system ground there now.

pin one is actually three point three, Eight volts. I'm gonna call that pin one. it's the black cancer, you know. Black, blue, red, orange, yellow, green, blue.

all that sort of jazz and 3.39 same third one over nineteen. Point four. What do we got? Nineteen Point four Again, three point three Point Three three. No idea what's doing there.

Zip-a-dee-doo-dah and zippity-doo-dah All right, let's plug the board in see if it makes a difference. Okay, that pin 1 is now dropped down to point 1. 7 Yeah, so if that was supposed to be a 3.3 volt rail, then we're in trouble. That's still 19.

That's the power. That that's going to be exactly the same. That's the same pin and three point. throw.

No, there's three point, Three Point three. Okay, well, not exactly sure what that means. But anyway, let's go measure it over on the board now. and what I'm gonna do is that there's the ceramic output caps on here and I'm gonna measure the voltage across those and zip.

So obviously it's not generating the compliance voltage required to drive the lead stream now. I've measured the diode in there and that's good. So what I'm going to do now is measure the power in that's on pin two. Cheese I Can hardly see that.

it's insane. Oh God. I can't even see that to probe anymore. Unbelievable.

But I can probe the bypass cap there. And of course we get the supply voltage. nineteen point Four volts. So yeah, the chips getting power.

but I don't think she's switching. Okay, let's probe pin five, which is the enable pin should be the top of this resistor down here. Uh-huh. it's not enabled.

Well, there's your problem. And I traced out the enable pin pin five. It went on the back of the board here and wiggled its way over to the third pin from the end there. So that is the culprit that is not enabling our driver chip.

No wonder the back lights not coming on. Whether that's deliberate or whether or not there's some fault causing that I Don't know, but we can certainly override that. All right. What I've done now is I've actually cut the trace going to the enable pin on there and it's got a twenty K pulldown resistor on it and I've tied that high.

So I'm basically on a force that enable pin I wanted to cut the track cuz I don't know what's driving. it could be direct logic and I didn't want to like directly shorted out, didn't want to go cutting cables and you know things like that. So um, yeah, let's try it. so we're gonna force this thing on.

no he kept in look, hey, it's hiccup in. oh no, hang on. that could be the power supply I may not have enough current limit I had it set to three and a half amps. Hang on.

No, it's not the power supply doing that. it's the power supply on here. just hiccuping and resetting the whole thing. You can see the LED flashing down there.

The power: LED up the top, switch up this soft switch on the top and you can see the fan just going twitch. It's gone. it's got nervous twitch, it just can't handle it. So uh yeah.

back my problem, the actual LEDs themselves and we'll give it another go. No whoa, this is heavy and here we go check it out. Actually uses an Mps 3389 which is a monolithic power multi string multi 12 LED string driver which is exactly what you'd expect to find here. And there are two power transistors it needs.

Here's the schematic: typical application schematic which is almost going to fire this precisely. So here's your two power transistors right. Here is your converter and Bob's your uncle, right? This thing should work, but it doesn't good. Now we have something to troubleshoot and before you scream at me, know, it's not the fuse there I've measured it all right.

So what I'm gonna do is that you just try and manually drive this backlight and so it you know it has the weird pain-in-the-ass little liar connector thing on it. So I just got rid of that and chopped it off well feed in some leads. I can always reattach and I'll use my Keithley currant sauce I got I don't know the drive current so I'm gonna set it to like a nominal 50 milliamps. that's what it has in the datasheet for that chip driving.

but we just, you know we. we just don't know I mean this board has the external drive transistors on, so it could certainly be more than that. but I don't know. 50 milliamps sounds fine and you need a high source like this because of course we're gonna have lots of LEDs in series.

There'll be like a strip along probably the top and bottom, or it could be the sides and probably top and bottom cuz then there's less range to go that way to actually project the light up there than it is to come in from the side. So I'd say they've got on top and bottom just as a guess. So we're gonna have a big string of LEDs in there. There could be I don't know, you know 20 LEDs or something all in series.

So let's say we had 20 LEDs and they're all white LEDs with a nominal say 3 volt voltage drop. Some of them can be much higher like up to 5 volts or something. 3 times 20 is 60 volts. so you need a reasonably high compliance voltage and my Keithley one here I'll actually go up.

Here's the compliance voltage knob and it'll go right up to a hundred volts. So we shouldn't need any more than that because the reason you can tell is because these wires are absolutely reason until it's high. Volt is just this: why is there absolutely tiny? So if it was like low voltage and it was driving them all in parallel or whatever which is a harder arrangement to physically you know, manufacture on the board. It's much easier to put LEDs in series is you'd need much thicker wires to get the same amount of power.

So obviously it's gonna be a low ish current like you know in the order of that 50 milliamps. Anyway, enough talking. Let's see if we can ramp this thing up and see if the LEDs come on. So let's turn it up.

hopefully. I got the right. Hey hello, hello McFly So it's about 40 volts there you go. so you know if you're like a nominal 3 volts per lead for example, like you might have, you know, you know, a dozen LEDs in there or something like that.

Got an interesting dark patch here. Are they side and projecting over? That's interesting? Anyway, let me swap that over to the other one because there's only two lead strings inside this thing and see. Ah, yep, it looks like it is side lit. There you go.

Looks like they got them just on this one side over here. That's interesting. Wow I Wouldn't have expected that I Would have expected them to be top and bottom in there. and if you put them on the side, I mean trying to get an even projection right across that sort of width? You know what Is it? 20 inches or whatever? 18 inches or something.

23 inch screen? I Don't know. Work out your angle and figure that out. but yeah, trying to get it right across is. um, ya know it's It's really quite difficult and that's a reasonable camera.

Looks so reasonable what it is actually in real life. Don't worry about that strip there, that's just a reflection off the wall over there. Power on. Whoa! hello I Saw something, saw a scan line but we don't have anything.

I Would have still expected to see some sort of image even if we didn't have very faint image. even if we didn't have any backlight because you're still going to get some external light coming in and then the reflector at the back. actually. would you know? bring something back out I would have thought.

Anyway, so something dull I actually had it set to the internal weight. um, a thing. so let's try that again night. Same thing all right.

hard drive plugged in, yet the current jumped up to two-and-a-half and so I'm not currently Medine I'm not entering current limit so it ain't that and it'd be nice if there were like some, you know, error beeps on power up, but I don't unless I'm missing it. I Don't see a buzzer on here anywhere like a system buzzer. So or whether or not that I don't even see like a you can connect your pin header thing for it. Nothing that's labeled anyway so that's a bit of a bummer.

it wouldn't but then again, you'd probably need like the service manual. Well I don't know. can you get the service man for this? Haven't even looked you? Alright So now that we've established that, well, there's something wrong with the bat light backlight by the looks of it and we still can't get any anything on the display. Let's start doing the basic PC stuff of eliminating issues like the stuff that we can replace like the memory are for example, and also removing the GPU card because if we plug I did try to plug the LCD into the UM a slot, but it may detect the bias, may actually detect that the graphics card is plugged in and therefore switches off that you may.

So if we physically actually remove that looks like I couldn't take out, Well, it looks like I have to take you up the heatsink from the CPU then take it because those bars go over the top of that so it looks like I have to remove that. So I've got some no one good memory. only 2gig each, but that's all I've got, so I'll whack those in there. Okay, let's test the memory and see if we get anything.

still don't see anything there. Hmm. and well, we found the word buzzer. So that's presumably the PC system buzzer, but like, where the hell is it? It's not.

There's no connected near it. What? or is it? it's not that I don't get it. Well, that came off very nicely. A little bit of crustiness in there, but there was just the one screw there and then the whole thing just lifted off.

I'll just re seat the Yost CPU here just to be sure. Likewise, this one should be pretty easy. There's just two screws on the bottom of the PCI card there, and that should just wiggle out. Beautiful.

All right, we have the video card removed, the LCD plugged into the UM A Let's give that a bill. 1.5 is drawing the same amount of well, the currents dropped. Yeah, Karen's dropped a fair amount, but zippity-doo-dah Again, not strong about nap and that's boo dude with a heart with the hard drive back in it so diddly-squat Alright, so the next thing we want to do is look at the biased chip on here because there's quite a bit of talk online that these things are need a bias. Either the bias chip reflashed or it to fit be physically replaced with a new one.

It's common problem with these HP Envy's apparently and there's the little puppy under there now. Thankfully I Believe we don't actually have to disorder this to reprogram it. We've got a remote programming header down here and I'll link in information it's on a website, thankfully I didn't have to go decode it myself. Some people have already done the hard yards here and we have the pin out for that and we can actually access the SPI bus for the serial ROM chip up here and we should be able to reflash it fingers crossed.

So here's the pin out for the ROM recovery header and it comes with two jumpers. Normally there's this black jumper in place here and that's the SPI chip select. normally that's shorted so we have to remove that and also move this top blue one from here over to here I'm not exactly sure what that does, but that allows you to access and reprogram the ROM It might actually are changed, like the external voltage or something like that perhaps? Yep, as suspected, one of those pins goes through to the power pin of the bias our flash chip. So I think that might be our switching between internal and external our programming voltage for that.

So we should be able to actually flush this chip but without applying power to the board by applying power externally which is on pin number five down the bottom there and we'll try and get the number on that there we go. I should be able to read that on playback because it's hard to work that huge thing like this under the mantas. and the good news is is that my mini pro programmer are supports this. you going here to wellSpan Ssin even though it didn't say it's the S25 here I Believe it is because it had the FL O.

Since 4k SOI C8 package is the correct one, you don't want the same one in a SOI C16, so it's that. So we should be our to information. There we go, we know exactly which pins do. Well, No, it didn't tell us which pins I Have to go look up the datasheet, get the pin out and know exactly which pins I'm hooking up There we go.

That's a 64 megabit CMOS three volt flash memory 80 Meg SPI Thank you very much. That's a really screaming isn't it? So if we go down here, we should be able to find the pin out. there. We go.

Tada! We can now compare that to our rom programming header and just why they strap over the pins should work. Unfortunately, it is not reading over current protection actions. External short-circuit I see reverse or damaged I've tried reversing the My So and Mozzie lines just in case. I goofed those up but no cigar? What? What? what? what? Okay, well that was interesting.

It turns out my little Tl8 six in six little Oh whatever it is. mini prog. Our programmer here couldn't actually provide enough grunt to power the chip directly. actually measured across the power rail on there and it was like seven hundred ohms with the meter sort of both directions.

So what? I Did has just hooked up. an external were 3.3 volt power supply on there and actually didn't connect. So I connected that and join the grounds together and then connected the 3.3 directly up to the power rail and what do you know? it? Read it in. Whoa.

Woohoo there it is. Read finished. It took what is it? no 8180 1000 milliseconds to read that in it. Read the ID Okay, everything's hunky-dory and now we can actually have a look at the data in here and presumably we show up cancel.

We should be able to reflash that, no worries whatsoever. So Olcha. I'll download the latest firmware wherever that is and simply reflect their you go. but I'll save this one just in case.

There we go. We're on the HP page now. we've got the buyers consumer Pc bios. update Rom blah blah blah blah blah.

Let's do it. Which one do we need? One of those two? I Think it's the dot rom. Alright, so let's burn that program and it should do the ID check first. Then it should take a while.

Yeah, could take a bit. It's a big flash and I was actually going to do a second verify pass, but it's already gonna do that for me. So I'll trust it as long as it's verifies. Ok, we're good to go.

If we can, program the entire 64 Meg bit flash and then read it all back again. you know you've got a winner. We know we're not kicking dinner. Ok, let's just turn it on just without the graphics card or anything for a minute and see if we get anything different to last time.

So clickety doo-dah 19 volts did something flush there. Soft power button switched on. something flushed over here. That's the hard drive.

Is it? No. There we go. No, it's just seeked 2.1 amps. Yep, I think it's doing something.

haha. Let me check the screen. it's all hard when it's all back to front like this. Still haven't reinstalled the backlight or anything.

All right. I've got the backlight. well I didn't put the PCB back on and still run it from the external current source. So let's power this puppy up.

And because I couldn't see diddly squat before so it's only got half the back away. Hello I 534 70s CPU sorry you can't see that well. Winner Winner Chicken dinner. No boot disk.

It works fine. That fixed it. Let's try that again. Had fixed it.

It was the bloody bias. Unbelievable. There you go. We've got our RAM got everything else.

Everything's hunky-dory. Nothing wrong with the graphics card. Graphics card works a treat and well, the backlight driver could still be dead. There's a chance.

but I don't think so I think that it actually switches that on. so hi Winner winner chicken dinner. so it's a bit of a Franken Monster at the moment parent from an external Ben supply with a external backlight driver on there. Don't worry about that train track on the floor that's just normal for the Eevblog lab.

Um, but hey, we got to go and unfortunately it looks like we do have a Fault in the LED driver board because I've put it back to it like I did some mods on there and to troubleshoot it and I put it back to its original state and nothing I mean thing boots but it doesn't draw any additional powers. Still, only draw in 1.9 amps at 19 volts and it's not switching on. So there you go. So it looks like we have two faults on this thing.

One was the bias which were fixed no workers and the other is the back line. So due to time constraints I'm going to leave it today. There might be a part two on fixing the backlight driver on this puppy because something is I mean I it like could be just the board or there could be something over on the main board actually causing some sort of issue or something like that like power supply over there hiccup in. in that case.

that's a lot harder than just fixing the board up here. or you know, even buying a replacement board or whatever if you have to. So there you go I hope you found that one interesting and we went down a bit of the rabbit hole there with the backlight and stuff like that. Originally suspecting that and it turns out looks like there is an issue there.

so I was kind of looks like I was on the money there, but I could have found the biased one earlier. Of course if I probably simply googled, you know HP MB 23 blank screen fault or something, it probably pops out because it seems to be a common problem. The bias on these HP MVS actually just corrupts herself. It just shuts itself after a couple of years and reflashing them is actually a common thing.

Hence there's you know, quite a few little tutorials and webpages and YouTube videos out there showing you how to do that. But yeah, looks like we have a secondary fold here, but there's no reason why I can't get this running even if I have to like you know, do my own backlight driver circle or something like that and wire it directly across the power input or something. You know you can get this working if you really had to. No problems whatsoever.

I think I'm gonna have to leave that to a part two. But anyway, we did get basically a fix for this thing to get it booting again, so that's not too shabby at all. If you liked it, please give it a big thumbs up. And as always, discuss down below: subscribe with a little over here with the little bell icon.

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