Hi yes, I'm a bit obsessed with Dynamic Signal analyzers DSA As you've seen my Uh previous videos on the Hp3 356a dynamic signal analyzer. Well, I've got another puppy. This is the HP 35670 a DSA and it's sort of like the big brother to that uh, previous model and this is still actually a current model unit goes for about $22,000 brand new and yes, it's not working or supposedly that's what the guy who sold it to me says anyway. and apparently he spent uh, says there was a fault with the power supply and he spent uh, 1,600 bucks.

Man, he got shafted to fix the power supply and apparently, well, that was fixed and it still didn't fix the problem. So hopefully we get a repair video out of it now. this one is, um, a 16bit dynamic signal analyzer. It's got a 90 DB dynamic range optional swept sign mode gives 130 DB dynamic range I Don't think it has the swept sign option I Can't see any options on the back anyway and it's seen better days I think But anyway, um, yeah, fingers crossed repair video and hopefully I can fix it.

Otherwise, it's going to be an expensive paper weight and here it is and it's a relatively modern looking unit at least compared to the other one. Anyway, yes, still has a 3 and 1/2 in floppy on here and uh, dual channel of course. Pretty much exactly. Uh, you know exactly the same functionality as the uh uh, previous one we've looked at, except it does have an external mic uh thing here which you can get like a separate module um to hook up, uh, microphones and um, you know, accelerometers and other things like that, but basically dual Channel plus the source and all the uh system uh stuff we saw before.

It's even got a basic key. brilliant and um, you know, marker works all if you use the other one, this one works just as well. But look, you can see the screen. there is just Something's Happened to it and it's likely not the uh, not the screen itself.

it's just the uh plastic or the uh filtered the screen filtered uh cover on that, the screened cover. So yeah, I don't know what. It almost looks like. it's some sort of.

it's like peeled off or some some sort of laminate is sort of Peel off that or something and people have been scratching the screen. I'm not sure if you can get that, but look, people have, sort of, you know, used a pen and sort of scratch things on there. But anyway, um, hopefully the CRT is still good so we'll um Power this sucker up and see what happens. It is, uh, significantly smaller and more compact than the Uh previous model and um, it also has a DC option as well.

There's a DC option. uh, there's a DC jack on the back and a big switch to select between 240 AC or optional DC cuz these ones were designed for field use hence the rubber bumpers around here and stuff like that. So not just for the lab, but to go out on site and uh, do you know acoustic and uh, vibration measurements out on site? You'd lug this thing but it weighs a ton I don't know, it's about 20 plus kilos or something. weighs as much as the old one and that looks like a cow date of 2003 there.

just make it out. but anyway, she is a fail. and it does come with a really, um, old school protective cover on it. makes it look really ancient.

I mean this is obviously one of the first models. probably the new one doesn't have an ancient looking thing like that and it would be Agilant branded as well. Um, the interesting part about that is that you can lift it up and you can store stuff in there. Um, really handy.

It's got an Allen key. um I'm not sure what. uh, maybe we need that to get into thing I Don't know. but it smells, smells weird.

it smells like WD40 I Yeah, I'm not sure it's some sort of lubricant oil or something. weird and there's the big clunking Source Select switch on the back. the Akaaka switch As I Like to call it but it's got a nice big uh protective um guard around that really like it. and there's the DC jack input.

It looks like some sort of limo connector. two pin limo off, hand on. not exactly sure of the uh exact type there and I'm not sure um what? DC voltage. Haven't read the manual but you know, presumably like 12 Vols or something like that.

and on the back all the regular star serial parallel external monitor which is really uh, quite nice if the internal monitor doesn't work Beauty um that could be a lifesaver, but yeah, there's no other options or anything like that. The uh C the Um seals have been uh, broken cuz this thing's been opened. um and yeah, there is no option written on there. So I was hoping to get the Swep sign option, but oh well.

you can't have everything and a crusty looking keyboard bought and just to prove that he did have the power supply fixed, he thoughtfully included the original invoice for that and check it out,. 1685 bucks for uh, repairing this power supply. Unbelievable and what do you know? the Ellen key fits Beauty this looks like it's got to be two easy let slid off. here we go I believe I can get the service manual for this thing.

haven't uh looked yet but this should just slide off and whoa we're in like Flynn can see some Gunk though. check this out, look at this. there you go look at that that's like uh I don't know what it looks like is I think something's been spilled through the back of this vent here and you can see the see the spill marks coming across there and it's run down into part of the power supply here and also across the board so that certainly needs to be cleaned up. That's certainly not Factory original.

You can see a Fair bit of uh corrosion on this uh metal work here holding the power supply in I mean all the aluminums are fine of of course, but this uh looks like this steel bracket here is um, you know, just sort of started to rust away. It's you know, probably been used in some sort of uh, you know, tropical environment or something like that and yeah, doesn't look great but shouldn't affect the performance. Now if you compare this with the previous video tear down video of the other DSA which which I'll link in down below, you can see that they've sort of copied the same sort of style. They've got the plug-in cards here with the little leevers to pull them out, the uh bracket to hold it in here and these cards all just slide out.

it's rather, you know it's rather nice design and then they've got the little uh coaxes connecting the boards exactly like they did in the other one. and on the top side, coming from the power supply here they've got the ribbon cable coming over which no, probably doesn't take the data like the other power supply. it uh, takes all of the Um power over instead of you know, discret wiring. It's just a neat a way to do it.

And they've really put uh, you know, quite a bit of thought into this. I Really like it. Lots of socketed uh Plcc Parts up here. by the looks of it, lots of test points that we can get to.

Unfortunately, they're uh oh yeah. Ground TP yeah 5 Vols Uh yeah Well, we should be able to measure a few things, but that's very thoughtful. Look nice little Post in there. you can get your escope probes onto and probe this thing while it's all still in the shazzy, which is fantastic.

And of course one of the reasons they're able to shrink the size of this thing down compared to the old one. even though the boards are still huge full size doesn't use a CRT Of course this one is an LCD base unit and we can see the chipsets in there for the Uh LCD display down in there. but uh, that makes it uh, really nice. um to troubleshoot.

although the weight of this thing, you know, still all that shield in and Metal and you know, like really, they've gone to town on the design of this thing. really belt and braces gilding the Lily stuff in terms of all the shield in and everything else. So that's why the damn thing weighs a ton. And on the back here we have some uh, Ventiles cable routing diagram.

Rather neat and it looks like the front panel board you can just access directly I mean there's the B&c's right there, right angle, presumably the right angle B and C's yep, it uh, baes up directly. You'll notice how we got an unpopulated BNC there. that's actually for the 4 Channel version of this and the 4 Channel version. Exactly the same as this.

but they, uh, don't? they use the source one here which is the the output on the two Channel version. that's actually um, an input channel on the other. So I guess they just changed the Uh cable routing and that's why they've given us a two channel cable routing diagram for the 4channel board. Um, actually, that's probably what this um unused slot here is the extra Channel board.

So they install the extra boards and then you'd have a particular routing scheme for the four Channel version and they use that uh, the source output comes from the back panel. There it is Source going to the rear panel and on this two channel one, they've also got the source going to the front as well. And once again, check out the RFI ah, fingers there that uh that connect the shazzy down to the case. Just keep all the RFI crap in or out depending depending on which way you want to look at it.

Generally for this sort of high performance uh Precision instrument at uh, you know, lowlevel Precision instrument, they're looking to keep stuff out and we have ourselves some PCB Mount Din connectors down in there. The other ones look like our standard Din 41612. First thing of course I am going to power it up and uh, just confirm that it is dead so fan goes so the power supply is going. We got our green power light there um but we're getting Zippity doar on the screen by the looks of it.

buger. All but uh yeah, probably worth measuring some uh test points now. although I think first step is probably download the service manual and yep, 5V rails okay at least on the main Uh processor board so that's a good start. Um, all of the other test points down here are unlabeled so you know you can go around and you know it's just got TP 240.

so you need the manual for that but you can go around and sort of probe those and if you you get you know voltages like you know plus - 12 Vols or plus - 15 Vols for example. then you know that there are power supply voltages. There we go 5 volts. The other Uh test points on here are all uh, various test signals from the processor.

But one thing that tells me that this thing isn't booting or is you know, having sampling issues or something like that A is that there's no beeping at all. You know you'd expect to sort of hear the odd beep or two I don't know I haven't used one of these things for like 10 years so I can't exactly remember um how often it beat. But the other thing is there are half uh Channel lights here for for half the voltage in the overrange lights usually. um I'd expect those to go out and of course you know, run the self tested.

Hear the reays as we did in the previous one, self testing and all that sort of stuff after boot up. Can't hear anything like that. All I can hear is the were of the fan and that's it. So it looks like that the processor is not starting up.

um, you know? uh, most likely. although we've got 5 Vols on the main board. Holy crap. I Just downloaded the service manual and it comes with no less than a 70 page troubleshooting guide inside the service manual.

Unbelievable, that's 70. Pages step by step of how to troubleshoot this sucker. Oh man, that takes all the fun out of it. really.

Now we're getting our green light on the power supply over here and I'm not sure. um you know how extensively it, uh, tests its own. you know, actually tests itself. but the power supply is basically working.

We've measured the 5 Vols so next thing to do is measure the 10 mahz uh main processor clock signal here and what do we get? What What what? what? look at that complete fail folks. Fantastic! I Love it. This is the kind of failure that you want. Um, you know, direct No.

10 MHz processor clock. Well that just you know. stop right there. go track down that problem.

fix it up. Brilliant! So that points towards our processor board down here. and uh, I'm not sure about the top board I have probed the gunk there and it's not conductive so uh yeah, not a big deal. Oh look, we've got some actel parts.

This is rather interesting. Let's check this out. Now this isn't the main CPU board that's actually on the top of the unit that's got the gun. Con: it.

This is the digital processing uh board. It's got a lot of 84 pin Plcc Parts Here, these are all socketed. Very nice. Now we're not getting the 10 mahz on that pin there Now whether or not that's generated on the board.

here, is that a No I can't see an isolator? We got a relay over there, but uh, most likely the uh reference clock. The system clock for this digital board is generated on the main processor board. So we could be following a red herring here by by, you know, thinking that there's something wrong with this board. although, uh, you know, a classic failure mode.

Maybe that, uh, some of the one of these PLC CES has become unseated or you got a dodgy contact in there. It's um, as a basic troubleshooting procedure. it's worth. Uh.

Also, after you've done the basic uh checks of course to narrow things down, but if you're scratching your head a bit, um, take these chips out, use a proper Plcc extractor or be very careful with a small screwdriver and just, uh, reat them. Or even if you don't take them out, at least give them a good push. Make sure your board is flat against the bench so you don't, you know, stress the board and crack any solder joints or anything like that. But just reating these sockets can, uh, solve a bit of problem.

It looks like we might have some ROMs under there directly solded into the board, which is a bit surprising. So as usual, these all have you know, the HP part numbers on them. So the Actel devices are, probably you know, uh, PS or small Fpgas or something like that. I'm not sure when this was designed back in the early 9s I think, um, what Actel were doing in that area.

It could could even be a custom, uh, you know, gate array part or something like that. Got some memory happening around here, but yeah, um, interestingly, we've got these sockets down here which have no load written on them into the silk screen if you can see that. So um, you know, at the PCB design stage, the PCB layout stage. the layout design is go well.

we know we're not going to load that. so I'm going to put no load directly on the silk screen. So maybe they're only for development or test debugging, uh, purposes or something like that. So anyways, just wanted to have a look at that board.

I'm not going to, uh, start troubleshooting this board because I'm going to go to the main process aboard on the top because I think that's where the issue is and of course, we have some visible signs of guny happening around here, so it's worth unscrewing. Unfortunately, we have to unscrew this bastard and uh, flip it over to get to the top side. but because it's in there with a nice re. oh no, that's the motherboard connector.

so really, uh, we can't access that and no test points are labeled on the bottom unfortunately, which is a real bummer. but anyway, worth, uh, taking that out, flipping it over and giving it the good old visual inspection. Now of of course giv that this has a no one power supply fure mode then uh, really. uh, we have to also consider the possibility of that the power supply you know, has failed obviously.

but it's um, also could have taken out something on the board and uh, well, you know, digital stuff is uh uh, you know, not hugely tolerant of uh, over voltage like that. All the 5vt I think it's like you know there's no 3.3 volt stuff on this I think it's all like old school 5V TTL level um stuff as we saw in the previous version. but uh yeah, they don't tolerate huge over voltages so that could be a real pain in the ass if that's happened and taken out multiple Uh devices. So yeah, um, in that case, you know it might be Beyond economical repair kind of thing.

Um, you know, depends on how many hours you want to spend. You know my I've you know troubleshooted uh digital boards that have had, you know, a dozen chips been taken out and failed and it's just not fun. It takes forever. So we've got some motherboard connectors.

These are ding connectors down here. Looks like I'm going to have to lever that out. Woohoo! Check this out Modern as look at these uh quad flat packs. all virtually all uh, surface mount construction on the main board here.

Uh, the main processor board? Unbelievable. We've got a memory board down here which uh, connects via this uh D 41612 connector down onto the main memory board. and yeah, you can get memory expansion for it. There we go.

looks like we got some standard uh, memory expansion sockets. we can just whack those in uh made in the USA stickers all over this thing. By the way. USA USA Um, there's an NSL lithium uh, battery backup.

so uh, worth measuring that. but of course that's not going to, uh, stop this thing booting up at all. But uh yeah, we can expand the memory. That's great.

Unfortunately, we can't probe this. We've got some uh, you know, without it, uh, being plugged into the top and uh, we've got some nice, uh, status leads over here unmarked so we'll have to look at the uh manual for that. We've got some uh, um, little secret uh squirrel switches on the back panel there and uh, Anyway, there's our Crystal that because we're getting no clock, we have to look at that. There's something interesting.

let's take a look at that. Check out the old School trimmer cap in there to adjust our main reference oscillator. Oh thing of beauty and a joy forever. And there's our main processor for all you Motorola fans MC 6803 And over here they've got a Motorola 56,000 series DSP They've changed from the Texas Instruments 320 DSP they had in the previous model and that sucker was end of Life back in 2002.

But ah, date code. there we go. 9506 So 1995 vintage B unit we've got here. but anyway, I don't see any signs of trauma on there.

There's no blowouts in the uh chips or anything like that, so you know I wouldn't rule it out, but uh, you know there hasn't been. you know, a drastic, uh, overvoltage on the power supply. so I might uh, whack that back in and uh, see if we can measure our main oscillator there. But what I'm going to do first of course is clean off the gunk and that batter is still good too.

although for long term you'd probably, uh, replace it. But for the purposes of today's repair, I'm not going to. Well, it turns out there is a labeled test point on here in the copper 20 MHz and uh, we probed that and we're getting Naf all look at that. I mean that's 1 VT per Division and there's just you know there's well, there's something thing there at.

uh, you know what, 150 200 molts or something like that, but that's just ground. Well, you know it's picking up some crap I don't know, but there's definitely no reference oscillator. Once again, fantastic result. We got something to work on.

Uhoh. all of a sudden, uh, our power supply green lead has gone out and we're getting absolutely nothing anymore. So um, oh, I don't think I touched anything and this is all rather nice. Popped off the back, uh, cover here just folds off and uh, we've got ourselves a separate board on here for the Uh Source output and uh, stuff like that and the Gpib and all sorts of other things.

some flat Flex there connecting those in so to get that panel out, you don't have to undo all the annoying Jack screws and Bnc's and things like that. So that's really nice system design. You can see the back plane that they've got in there, so this board top board here plugs into a right angle one on that black back plane and then the other the slotting cards plug into. there got nice right angle ribbon cable here.

Ah beautiful. And there's inside our switch mode power supply. Quite a complex little uh beast. but uh certainly uh, you know it's you know it's well laid out in terms of uh, what it's you know, sort of real belt and braces, kind of, uh, power supply engineering there.

We can see how. there's our ACD see Aaaca switch on the back There there's a front panel power button which then goes through a sh flexible shaft there right through to the selection switch on the back. There very very nice and uh but yeah, this is an example of um, unfortunately you know I You know the power supply was fine, it was working fine. Then all of a sudden bang.

well no bang, our fire, our lead just went out and we get no power to anything. So it we may now be turning this into a uh, power supply troubleshooting issue. Maybe the fault on the boards that caused the power supply fault which we don't actually know what was wrong with the power supply? uh maybe it's taking out the power supply again cuz it's been powered up for too long or something I don't know. Anyway Murphy get you every time.

you can see small attention to details like the temperature temper sensor down on that heat sink there. so they've got some overt protection on that uh switching transistor there with that relatively small internal heat sink. Very nice. Um I can't find any internal fuses in this.

Doesn't look obvious I don't have a schematic of this, by the way. And by the way, the service manual for this DSA does not include the schematic. It's got extensive troubleshooting, a block diagram, and everything else. but Uh doesn't have schematics of the main unit, let alone this, uh, third party power supply.

So I don't know something's gone. It certainly wasn't giving 5 Vols out whether or not it needs something you know, uh, something to read back or something like that in order to power up the supply and generate the 5. Vols it might have an automatic cut out or uh, something like that. I don't know, but uh, nothing.

obviously blowing here I can't smell anything, can't see anything. So so ah, I was hoping not to do a power supply troubleshooting I like a good digital board level troubleshooting. That's what I was hoping for and it was looking that way, but a bugger. Regardless of what we switch on there, we've got some decaying voltages on some of these, uh, output heat sinks here and uh, so it looks like we're just getting nothing on the input presum like I can't get in there and probe the caps and stuff like that because I'd have to get to the underside of the board under there.

By the way, extremely uh, very high voltages inside here. You don't want to be around with power supplies um, switch mode power supplies unless you know what you're doing. but yeah, we just got basic decaying uh voltage on the on the secondary side there, which indicates that there's absolutely nothing happening on the primary to drive that uh secondary. So something has gone kaput on the primary side.

but thankfully we have that DC input here. Maybe I can try that and see what happens. Maybe it's the AC part I don't know and there you go. You bet you green light back on and we're drawing almost an amp at 12 Vols with no load on here at all.

So anyway, we're back in business. so I don't know I'll troubleshoot that main scene later I'll just uh Power this thing from uh, 12 volts and continue troubleshooting. Oh by the way, uh, this input accepts anywhere from Uh 12 to 28 Vols DC So pretty decent range and we are back in business. External 12vt DC power at about 5 amps.

that gives us about 60 OD wats uh, power consumption for this thing and that two pin limo connector in there I'm not sure exactly the type, but uh, the contacts in there precisely um, or seem to precisely take a standard 2 mm uh test probe pin. So hey, hacked up some old probes and we're good to go. There are actually some test points on the back of these there single in line headers here and although they're not marked on the silk screen on the bottom cuz there is no silk on the bottom which is really rather annoying. Um, you can get the reference from the service manual so 1, 2, 3, 4, 5, Pin five There that is the main CPU reset line.

As you can see, it's high and uh, which it should be of course and I can push the reset button on the back here and I can watch that go low so that's all working fine. But I cannot get any of the clocks on this thing at all. So there's uh, several clock points on this thing and I cannot get any of them. So that is the first Port of Call and Next Step apparently is to test the I Squ C bus.

I'm not sure what it's actually connected to or what it's uh, testing, but pins one and two of this single in line heada here as we actually power the thing up and it's supposed to give a couple of a couple of bursts upon power up. and uh, of course you know it doesn't. It gives zip where the Uh, 80, 70 or 80 page troubl shooting guide stops because it says well, if you don't get those clocks and if you don't get the I Squ C burst at power up there, then this A7 board it's called um, this is A6 this is the A7 The main processor board is faulty in quote marks, so yeah, well, obviously um, part of that clock circuit up there. It looks like a discrete uh transistor job.

So um, yeah, it'll be handy if I had the schematic. but uh yeah, it's still doable and we got ourselves a little socketed uh E prom there and that's um, obviously the I Squar C bus device that those two pins I was probing before. it's got a talk to that uh Es prom on power up so it might be interesting to actually, um, have a read of that. But anyway, um, that is not going to happen unless you've got a main clock and there's our main clock uh circuit here with our um I just uh, tweaked this little trimmer here just to see if it did anything.

You know it may have, uh, you know I don't know, sure doubt had some sort of gunk in it or who knows. but uh, I was just playing around with that and uh cuz we can always re trim it later and no, makes no difference. So it looks like we've got a um, that's a 39 645 MHz I think something like that 845 MHz Crystal and uh, we're getting no oscillation around that at all. that little uh thingy down there is a 79 l12, uh 12 volt voltage regulator I believe.

but once again, it's hard to probee this stuff because this board to work gets all its power from the main motherboard connector here, which to put it in, you've got to put it in upside down of course, unless you want to take out the motherboard connector and the power supply and oh, it gets all real nasty. so uh, rather difficult to probe and you'll notice that there's no silk screen designators on the top here at all. which uh, makes it a bit harder. But of course the service manual has overlays and stuff like that, telling you where the various uh, test points and things to measure are.

but that's where I've gotten to at this stage. Um, no clocks anywhere on this thing. got to be something to do with that discret transistor oscillator down there I can't see anything else I mean you know there's another Crystal over here 24 MHz but that's for the floppy controller here, so it looks like everything is derived as far as the processor goes from this main. Crystal down here.

check out what? I Just sort of found sort of hanging in there and just sort of pull P that out. Obviously there's a little nice little limo connector there that's probably going through. maybe to the microphone? uh yeah, that'll be the microphone connector on the front panel. Love these little limo connectors.

Very nice, but a man, they're expensive and this Crystal oscillator circuit here? totally weird I don't know what's going on at all. We've got the uh almost 40 mahz Crystal here, but it's in parallel with a very low value 1.5 ohm resistor and I've never seen well can't say have ever seen that configuration before and it's between. It looks like it's between basically the via the Um series uh, series cap there and via the series trim cap here. um between the emitter of two transistors.

I've checked those out they appear to be Npn transistors and well, I I don't know I haven't reverse engineered the whole thing, but it just looks really strange and I'm not sure what the hell's going on there at all. I mean I mean if it was a cul pits uh configuration, you know we'd expect to see one end of the crystal going down to ground or one end of the series cap going down the ground or something like that, but that doesn't seem to be the case so it's likely A A variation of the Pierce configuration. but I don't know I I don't like it at all I Got no idea what's going on here and I cannot find a schematic for this thing at all. hopeless.

It's not in the surfice manual um, surfice. Manual's got lots of great top level overlay stuff and Signal names and stuff like that and test points but doesn't have the schematic. so I'm left wondering if there is actually a fault in this thing. I mean I could probably get I'm not going to get the exact 39.845060 and see if the oscillator at least starts up cuz that Crystal could be, uh, physically damaged, perhaps? um, something like that or that.

there's some other control signal shutting down or some other thing. um, shutting down the oscillator and not allowing it to start up so you know the folk could be elsewhere. and the oscillator could be a red hering. but usually you know, you don't.

You know you. Um, you don't shut down the main oscillator on on on a product like this. It just it just doesn't really happen. It's just usually free running.

you power it up, it's free running. and Bobs your uncle and what do you know, an old video card came in handy. 40 mahz that'll do. We'll give that a B.

Well, that was a long shot and it didn't work out. so it's exactly the same as before. So I put the old Crystal back in and uh, we have to start probing around further. I don't know.

Um, like the power good. The power supply has a couple of signals coming out of it. There's a power, a good, uh, signal from it and that's all okay. and you know, I'm sort of running through the test points in the service manual and they all seem okay except for the fact that there's no clock there.

Well, when in doubt, measure voltages I've had to to get in there have solded a couple of pins onto that 79 L12 voltage regulator on the back. so let's uh, have a look. that's the input -9.2 Okay, um I think this uses uh, plus - 18 volt rails, but you know, okay, it's there. And the output minus 1.85 Vols Something's wrong there.

So either that regulator's gone bung or uh, uh, something is dragging it down and we'll just measure the resistance of the output rail of that No. 6.8 K Of course, the figure Meaningless. She's just looking for a low, you know, a low impedance uh path there to load that thing down. but no, that's no problem whatsoever.

So it's not like the output of that regulator at least. um, you know, just at sort of, uh, the low voltage from the Uh multimeter is not loaded down. so possibly, uh, we might have a dud voltage regulator there now. Of course, there's a couple of ways you can, uh, attack.

this one is to, um, uh, try and, uh, remove a component or cut a trace or something to disable the output of that. I.E remove the load and see if the voltage is, um, you know, actually comes good and then you then you can isolate it either to the regulator or to the load itself. Or you can lift the pin maybe if you're really, uh, careful, something like that I don't think I have any surface mount negative uh, 12v RS there, um in stock. and of course it looks like it is, um, you, you know, powering some part of this oscillator circuit cuz sort of this.

if they got like the ground plane cut out the bottom. this whole section here is this oscillator, so no wonder the damn thing's not starting up if we're not getting that. negative. uh, 12vt rail there.

And of course, if they had easily accessible test points on the bottom of this thing labeled like they don't even have silk screen on this board, but you don't need silk screen if you're trying to save some dollars. Not not not sure why you would in a $220,000 instrument like this. Makes no sense I'm not sure why they left the silk screen off at all, but anyway, you could have at least itched them into the copper on the back or something. Plenty of room, very sparse layout, plenty of room for labeled test points, so no excuse.

poor design. and uh, by the way, if you have a look at the tracers on this thing, this thing is completely, uh, looks like completely Auto Routed. Really? it's just, you know, right angle traces everywhere. Um, you know, a human hasn't really had much input into this sucker at all.

You can see the various layers, one going One Direction the other layers going the other direction and just you know, no real after tidy up. Uh, done. Essentially. So yeah, not nice and I budged in a crappy old To2 27912 uh Packy's probably 25 years old, 30 years old from my junk bin.

but it works I measured it and we're getting -12 Vols out. So that regulator was foldy. Um, we're drawing more current now. it was drawing just under 4 before now St in 4.9 because the damn thing is now T You bloody Beauty look at that.

What a winner. Okay, let's power it on again. I've got the uh screen and the keyboard plugged back in so it to should, uh, draw even more power. There's some uh status leads on the back here which were given an error code that are in the manual.

so uh, but that could be anything. Let's power it up. Oh oh look look bloody. Ripper look at this there it is.

a What a Bobby desler booing system. it's working. Woohoo! I'm not going to say that's all. Oh, hardware error.

Ah see fault logs. Yeah, okay so yeah, that was a fault log. The leads are flashing, the half leads were flashing down here. Calibration in progress: a Bloody Beauty It's looking like it's working all right.

The screen works, that's for sure that dodgy, um cover on it going to have to take that off and hardware error C Fault log. but uh, calibration fire change state of Auto C Remove this message blah blah blah blah blah. But at least we've got the thing to boot. So there you go.

It was a that um, 79, 12v, 79 L12 voltage regulator of course I'm going to have to get proper s so8 package one and stick it back in there. don't want to keep my bodge to220 in there. that's no good. but uh, that folks is fantastic and I go from excitement over that Wi to the BNC input connectors I Just noticed they're a little bit, uh, crusty in there.

Um, not the best. I Mean they're still usable of course, but uh, maybe you know if you're restoring this thing, you might want to, uh, go in there and possibly replace them with some some brand spanking new ones. They've had a bit of wear and there's our fault log. uh I Squar C No device acknowledged.

Uh. occurred 6126 No idea what that means, but uh yeah, we can, uh, follow the extensive troubleshooting in the manual and uh, track this down. um, bit by bit calibration failure yeah, don't know what's going on there. Um, but hey, it seems to be you know, generically booting up and working.

we're getting a fault code on the LEDs on the back. We need to check that out out the cross referenc the uh table in the manual, but this thing is, well, at least we're at point where we can actually you know, use the thing and uh and start troubleshooting. Well I'd better not get too excited because the uh, quick self confidence test failed now. I've gone into some more specific tests here: I did the ADC Gat array test.

It's failed. Um, you know, like display? Well, display is obviously working. Let's try the digital processor. Let's try all the digital processor.

Pass pass pass. Of course the digital processor is going to work otherwise we probably wouldn't get to this point. So that's all sweet. But uh yeah.

ADC Gatorade doesn't sound good. Um. inputs? I don't know. Let's test them all on the channel one.

Yeah, yeah. disconnect? Yeah, yeah yeah. Offset fails. Yeah.

got various fails and you should have seen the list of um, yeah, not good. I Mean the guy said he sold it to me, said that yeah, it was working before the power supply, uh, failed. but you know, who knows what the power supply is taken out so oh, could be a long road ahead. But anyway, the quick confidence test I mean that's just.

uh, many pages of fail on the quick confidence, let alone the long confidence test. Check that out. Boom n Well I've got a machine that boots but doesn't do much else I'm afraid. Well, we at least got to this point better than nothing I guess And hey, we at least got something that we could actually repair and get working again.

At least to a basic level. This could be Beyond economical repair I Don't know I'm gonna. there's a lot more steps I'm going to have to go through to test individual modules. Can't possibly do it today.

Not a chance. So uh, we're going to have to leave that for future videos. but I hope you like that We did find the problem. probably could have found it a lot quicker if they had the mark test points on the Uh top there you know, accessible test points and Mark because you know the golden rule of troubleshooting Thou Shalt test voltages and sure if they had those test points there, I would have tested them straight away and I wouldn't have suspected the crystal something else in the circuit or something.

uh, you know, reset lines and all sorts of you know things like that. checking out all that sort of stuff and H would have found that much quicker. but hey, you know it didn't take that long in the end and I found it and it's at least back up and running. So we have a baseline to work from.

um, Eror codes, red leads flashing in the back and I've plugged in the rear panel that wasn't the I Squ C uh issue and things like that. so I don't know. Anyway, if you want to discuss it, jump on over to the Eev blog. Forum Hope you liked it.

Catch you next time.