Hi, Yes, it's Vintage Computer time again. And yes, we're going back to the 80s my favorite decade and we're going to the UK this time around to take a look at the Acorn. Archimedes A 3000 personal computer dates from about 1989 or thereabouts, there is uh, an Archimedes version. The A started with the A or the 300 model.

this is that was 1987. This is a 1989 model so we're talking about. you know, 23 24 years ago quite some time back, developed by Acorn Computers in the UK Uh, they were very popular. This is the BBC micro Uh branded model and it was the last uh BBC Micro computer ever made.

They started back in the Uh' 70s as a uh, well, not really spin-off um as competing to uh Sinclair Uh Computers. The who founded Acorn actually used to work for Sinclair and went well bug of that I'm headed off to form my own company Acorn and if you want to get all the really great detail on that, uh, watch a movie called Microen It's fantastic. Highly recommend it. and uh, this is uh, one of their, well, the last BBC Micro machine.

Now one of the most famous things about this is that uh, this was Uh uses the first Arm microprocessor cuz a lot of people. Well, everyone's familiar with the R Micro, right? It's used in all your phones used in everything these days, but a lot of people don't know it actually came from developed originally by Acorn Computers back in the80s and uh, it started with the Arm 2 process and there was no Arm. Well, there was an Arm one, but it never made it into a production machine. So this one uses the Arm 2 architecture and Arm stands for Acorn Risk Machine.

Go figure. So anyway, this should be really interesting and and it doesn't work. Supposedly got it from eBay and uh, it said there's no video output on it so hopefully it'll turn into a repair video as well as a tear down. you know I hate it when I buy stuff on eBay and they just work.

Unbelievable I Want something that doesn't work for a change? Let's go find out. And here it is as a all-in-one Uh unit. Very similar to the Amiga of course and the Atari St of the day. Now the previous version to this in Uh 97, the 300 model it was a separate keyboard and more of your square box uh type thing.

This is the A3000 which is the complete integrated unit and uh, interestingly I Like the fact that it uh, basically copied the IBM Pc80 keyboard layout. really it's essentially identical. said they got caps locked down here in standing control up here but you know it's essentially identical. I Assume that would have been a decision to make it, you know, appear more more professional.

Everyone was copying IBM back in the 80s and everything they did so this sort of at style uh keyboard form factor became a bit of a uh deao standard and as detailed In the movie The Microman this is a Uh BBC microcomputer the British Broadcasting Corporation the TV network they gave the contract to Acorn back in the Um 80s to develop a Micr computer for a new Uh TV show they were going to do because you know micro personal computer Revolution was all the rage and they gave them the contract uh famously over uh Clive Sinclair much to this Clive's disgust of course and uh that uh makes the premise of a lot of the premise of the Microman movie and if you believe the history, one of the reasons they chose the name Acorn is because they wanted it to be before Apple in any Uh directory. There you go Well they fail because Acorn are no longer around and uh are going great guns go figure. Although their legacy does still live on that arm processor is now used in you know 95% of the world's mobile phones and unfortunately this one is engraved with the name of the school uh the Bigel or Plateau School here in Sydney that it came from. A bummer.

Anyone know how to get uh removed scratches like that? You can buff it out I don't know I'll just leave it there I think we've got our vent holes on the top here I have no idea how uh warm this sucker get but on the side here we got a Um 3 and 1/2 in floppy and nothing else on the other side except the power switch but on the back here. Curiously, check out the Uh expansion connector uses the classic Uh D 41612 connector that's used in the Vme bus sort of, you know, the industry standard industrial uh expansion connector I love that I don't know how many other micros of the age actually used the um the 41612 connector analog RGB monitor uh, mono video out headphone Port parallel printer uh 9pin serial port and econet uh which I guess was a modem interface and there's some sort of serial number card in there I don't know what's what's going on there. we'll find out when we uh, open that sucker and uh, no. I power connector just a fix cord and there's also a big expansion slot on the back here which uh has nothing fitted obviously but you could get Mighty ports and uh, you know, various other expansion I think there was even an Ethernet option or something like that as well.

And there's one thing you won't find on the back here though, which was of course uh, any uh, big high-powered machine like this for its day of course used a graphical user interface. where's the mouse Port Well, it's on the bottom and there it is tucked away in there. I mean it's a little uh D plug in there and that's pretty horrid. I Mean you know, almost as if like it's an afterthought.

Oh, we'll just whack it on the bottom instead of the back. I Don't know what they were thinking there at all. just crazy. You also see that there's a removable cover here with a space for two AA batteries, but there's no contacts fitted in here at all.

So I guess that didn't have the option and that was for the uh battery backed memory option. And as you can see though, relatively, uh, serious about the air flow on this thing. there's some fixed, uh, plastic standoff feet molded into the case down here. uh, presumably this uh was for an expansion, that part of the expansion connector, the 41612 expansion connector up there, and uh, yeah, vent holes.

So the power supply is going to all be in this part and they wanted to get some air flow through the thing cuz these things use quite a bit of power. And for the offici and AOS playing along at home, there's the serial number designed and manufactured in the UK by Acor computers. Cambridge England Fantastic. Copyright 1989 Good Year Apparently 2 Meg of ram fitted and Power on no video.

so I don't know when uh, that note was written and how long it's been in that state or even if that's right at all. Only one way to find out. Power it up! Yeah yeah. I'm going to break my own rule by turning on before I tear it down.

Sumi I've got the scope hooked up to the mono, uh, composite video output. so let's switch it on and see if it, uh, see if it works. No, we saw that go high, but uh, that's just stuck there. We're getting no composite it.

I Do hear a beep, but there's uh, there's no video coming out of this thing I Don't hear the disc drive or anything. So excellent. This gives us a chance to crack this sucker open and uh, maybe do some troubleshooting. That's the plan anyway.

and uh. a that's a good fault to have. Like, well, good and bad good in that you know we've got a defined fault. no video.

But why has it got no video? Is it part of the is it, uh, the video circuitry at fault? Is it the uh, um, is it the digital part you know of the ROM's gone bad? Um, all sorts of stuff that it could be? Couldn't be as simple as the power supply. Of course, that's the first thing we're going to check. First Rule of troubleshooting: Thou Shalt check voltages. As it turns out, the design has been very nice and they've given us these tabs here which allow us to just snap that oh, top cover off That was the floppy Drive uh, going a bit how you're doing there, but uh, that should just lift off and that's really quite neat.

Yeah, the floppies are flopping around in the breeze no pun intended, but there you go. Very nice. Not too Dusty either. So pretty.

Uh, standard construction technique for the day. and for this uh model, uh, you know style of machine. the all-in-one integrated uh keyboard. the slightly sloping keyboard which just lifts out to reveal the board underneath there.

the main board. It's just got one single main board. We've got some uh, a bit of uh, expansion that looks like our memory expansion board there. We've got our the Econet uh module on the back and separate power supply board with a uh, safety cover over that.

And the good part about this machine is that we can get the full service manual and Technical reference manual for it with the full schematics as well. Fantastic! So I'll link those down below and it looks like they're not just crappy scans either. Looks like they're from the original digital format, which is great. Now we'll take a look at this in.

uh, more detail later. I think but uh I just want to. I'm going to lift the keyboard out here and have a basic look around to see if there's anything obvious and then we might power it up and just measure the supply voltages as a first step. G Check this out.

The battery has gone kaput and leaked all over this board. Look at that horrible green all in the contacts of the chips down here. and even when I pulled out the keyboard uh uh, flat Flex here you can see that I think possibly some of the uh contact has come off there. so oh, that's that's pretty horrible and well, it's likely that's the reason this uh sucker is not going to work at all.

that is I'd be surprised if that didn't have any effect on this thing whatsoever, but we should at least uh Power it up and see that the supply voltage is correct. but this is going to be a pretty horrible repair look at that and of course one thing you'll notice is that the battery is missing, so clearly you know hasn't just uh, rusted and fallen off. I Don't find it in here. so somebody has had a crack at this thing and uh, well, they've opened it up and maybe the battery did fall out or something.

they've gone that's not repairable and just throwing up the hands in disgust, but that's pretty awful leakage. Look at that. and all of the date codes on our chip here seem to indicate a, um, a rough manufacturer date of early 1990. I Mean here's the arm to processor there it is woohoo in all its glory and uh, basically everything is like early '90s but if we have a look over here at the ROMs on this thing, they got 1992 on them.

so I can only presume that you know this thing didn't hang around for manufacturer that long then it wouldn't be using chips that old I Doubt it. So I reckon maybe someone has got in there and uh, replaced? uh, some new risk OS uh well, risk Os3 ROMs at a later date after manufacturer. So as a rudimentary first test, we're going to measure the supply coming out of this thing. There's only a single uh, red and black 5 Vols coming out of here, there's a um Earth uh connection.

but that's it. So pretty much it's it's all 5V logic on this sucker. So hey, there we go. 4.97 spot on.

So yeah, it doesn't work. so yeah, maybe look, you know we've got ROM uh, you all sorts of corrosion in the contact on these ROMs down here I mean I'm surprised I'd be surprised if they're still intact. Looks like, you know Mouse uh circuitry around there. but yeah, that's just.

it's not going to work if the ROMs aren't working, that's for sure. And there's plenty of Uh custom Asic devices. As I said, there's the Arm Acorn processor manufactured by by V LSI and if we have a look, there's plenty of V LSI stuff around here. There's another one.

It's got a uh, looks like a memory controller. there custom Acor memory controller? what? and the um as usual in the U looks like they've given them uh names. Very common back in the day. Arabella there we go.

Whatever that is like, that's a like expansion or something I don't know I haven't actually uh, read the uh technical, uh description of this thing. uh, parallel interface? something like that. And then we've got the Albian chip which looks like it handles the parallel printer port stuffff plus other stuff. and you don't see memory in those single in line packages anymore these days.

Unbelievable. And uh, of course they've got an expansion board up here that's for an extra one. Meg So there's one Meg on the main board plus one on the expansion, but it was capable of expanding uh far beyond that, just in case you get lost around the circuit. So I'm not even going to bother.

uh, probing around here. You know, the main oscillator or something. see if the processor's running? Really? You know? if you want to restore this, you've got to clean up that anyway. so you may as well do that as a first pass.

There's a couple of more screws down here. There's one little retaining clip there, and uh, that pops out. Looks like no damage on the bottom, so we look to be okay there. There is some uh, surface mount action happening on the bottom.

We got some surface mount resistors there, the odd cap that's interesting and I'm definitely going to want to get these ROM chips out. They go in this order 1, 2, 3, 4. They're nicely numbered for me so I know to put them back in the right place. And yeah, we got some corrosion on those pins.

that's no good. Oh yeah, some of the pins in this socket look oh pretty awful. In fact, we might need entirely new sockets on this thing. I think and of course I can put these ROMs in my uh Eomp programmer and read out the contents as well to see if they're okay.

I don't I presume you can get maybe the ROM dumps on the internet uh, somewhere like that if the chips had actually failed. but uh, these are mask, uh ROMs So it's not like their um eoms and the contents um, these will be much more reliable than the windowed Eom type which can, actually, um, have their uh charge bleed out over time, so these ones still should work a treat. But those sockets are horrible and that is truly horrible. Look at that.

You can see that one half of the Dual WIP contact in there is just it's just completely falling out, absolutely atrocious, and other one's just H completely rotted away. Thankfully, the pins on the ROM chips look fine. So I think if I just, uh, clean those up, then uh, they shouldn't be a problem. I mean the the pins on the IC obviously uh, different, uh, type of metal which wasn't attacked nearly as well as these sockets.

but that's just that's just garbage. Yep, definitely going to need entirely new sockets on this. Have to desolder them out. And oh, look, it's almost pretty at the colors.

Wonderful. Now the real problem with this sort of corrosion of course is that it can get under the solder mask of the PCB and it can start attacking the uh copper tracers as well. And well, if that's the case, we got a big bus on the uh on the ROMs here and you know could be all she wrote. you know, on unless you want to go around with uh, mod wires and all sorts of stuff.

but if it has made it through to those traces, yeah I don't like our chances, but maybe you know we could replace the so have to clean up of course. and then if we replace the sockets um, we might be able to and the keyboard connector, we might be able to at least get the thing to boot. You know, maybe there's something around here which is really that NOP that resistor just popped straight off there. Better find out what value it was.

Anyway, we got the service manual, but yeah, I don't like the chances of the mouse Port working here, that's for sure. Well first of all, I'm going to get in there with some isopropanol alcohol and uh, just try and get a lot of the uh surface contaminant off with the very stiff. This is one of these conductive uh brushes so just want to try and get as much of the Crut off as I can. You can see all the crud which is really uh, rubbing off there, but then I'm going to run over it with some of this uh, flux clean stuff, but really, it's looking pretty crusty now.

I'm going to get this socket out I've cut out the internal uh supports there and you can do it the oldfashioned way. just wiggle it uh, back and forth fatigue those pins and then you can pull out the pins one by one from the bottom side. Otherwise, you could use a proper D soldering tool. And of course, once we've uh, tried attempted to get all the gunk off, we're going to have to use some sort of corrosion inhibitor to, uh, stop it corroding even further.

but as you can see, it looks like it's the corrosions already gone pretty far. So really, you know you've got to repair the damage and then and stop it longterm. The longterm prospects of this thing are H just hopeless and you can see how it looks like some of the corrosion has started under the solder mask there. So yeah, the connections might still be in place if we're lucky across these tracers, but you never know where one is broken.

But yeah, you could clean it up and fix it um, and possibly get the machine working. but the longterm prospects of this thing are just don't even want to contemplate it now. Unfortunately, I can already measure that. There are brakes in these tracers and more than one too.

Unfortunately, that. should be buzzing out from that PIN to that pin cuz there's a lot of common pins on these. um ROMs of course and some of them I can see they're electrically supposed to be connected, don't even need to look at the circuit for it. and there's no continuity there at all.

So clearly the corrosion is eaten away at the Copper tracers under there. and I don't even want to think what's under there surface stuff I don't know, it's just all. it's all horrible. You know.

as I said, you might be able to get the thing to boot if you uh, put the ROMs back in of course, desoldered all the uh pins, put in some new sockets, put the rins back in. uh, buzzed out every single connection and then repaired the ones that are faulty with either at the board level. uh, like this? You could do that before you install the sockets. Um, or you could use uh, mod wires on the back or something like something ugly like that.

but H there's a well. there's various ways to repair PCB tracers, but no. I'm afraid to say this one is a bit of a loser. I'm I'm not sure whether or not it's worth the effort to resurrect this thing.

Um, anyway. I'm I'm going to I'm definitely not going to get it working today, that's for sure. So sorry about this I Thought it would be an Electronics uh, troubleshooting issue, not a corrosion, uh, repair issue. which it, uh, it clearly is because the thing is not going to boot with all those corroded pins which just fell out of the ROMs that's clearly why it.

uh, it didn't uh, boot at all and gener didn't generate any video. Um, although I haven't looked at the circuit. what actually generates video? Uh, whether or not you know there's like a a blank video there without the process of booting or something like that. I I Don't know.

but anyway, that's a loser. Um, sorry folks. Anyway, if you got any good ideas, good suggestions for this thing, maybe I can uh get it up and running in a follow-up uh, video. but m bummer.

Um, if you want to discuss it, jump on over to the EV blog Forum that's the place to do it. Catch you next time.