EEVblog

Dave powers up an old Lecroy 9384C 1GHz oscilloscope.
Will it work?
And what's inside to make it tick?

[@DanTheAppleMan]

Love seeing all the bodges on these things, always a pleasure to discover. It adds some personality to the boards.

[@StrapMerf]

second tear down for me to watch(picked at random) 2nd piece of kit I've used recently(2016 for both, the other phillips PM66..) The Lecroy diagnostic menu was a hidden menu, you needed to hold down two of the side menu buttons (I dont know which ones) Love your work..

[@akkudakkupl]

Seems memory might be dead? Love that amber display, too bad the phosphor burned in.

[@nekomasteryoutube3232]

akkudakkupl Ahh, burn in isn't too bad if you can see what its suppose to display, I dunno how that will effect O-scopes, but from my experience with CRT TV's and old CRT monitors, even bad burn in isn't too bad until you see ghosts of images blocking out important things like subtitles or people

[@ivanv754]

I was a bit disappointed in the previous video because you didn't find the problem, but I am happy now. :)

[@MercenaryNL]

Nice video; I was wondering if you were going to try to troubleshoot the problems. Will be waiting for that video.

[@FXGreggan.]

That's just simply beautiful design of the motherboard....

[@epatto]

I saw a few 0.1" headers labeled TP, so those are probably the test points.

[@ubuntututorials]

I would think the crystal is damaged. Sometimes they can crack and give erratic behaviour. The vibration from the fan might be causing the jittering and the jump in the middle of the waveform.

[@Pizatto2]

There is another bodgy resistor in IC A15 at 26:33 :)

[@CampKohler]

Looks like a second scope will come in handy for fixing this one. Note that the Ch1 & Ch2 ADC heat sinks aren't just shorter (to clear the PS), but also have a different footprint and metal thickness. That's odd. The loopy coax looks like it's longer to achieve a timing objective. If the RAM stick is std., you could change that out just because you can. Do you have JB-Weld in Aus? That would be good for case repair. You could drill fine holes into the thickness of the case and force in glue.

[@turbochargedbrick]

the ULN driver is obviously for software control of the relays on the front end.

[@0LoneTech]

Those Darlington arrays are probably for actuating the relays.

[@EEVblog]

@pidgeoninthecoop That answer has too many variables... Depends entirely on how much ground work you had already done and experience gained on previous designs, partitioning of design teams, project management etc. It could be as little as a year, or as long as several years.

[@AlexForencich]

The coax cables from channels 2 and 3 are probably to get the trigger to work properly with the PP094 adapter for 4 GS/s on channels 2 and 3. The other pair of coax cables probably connect two out of phase PLL outputs to the channel 2 and 3 ADCs for this adapter as well. The final coax cable is probably used to connect the standard sample clock to all four ADCs.

[@wongstein]

Great video. Very useful comments. I think the extra power supply output and a lot of that space might be for an optional on-board thermal printer which some have.

[@ginbot86]

I'm sure it's been said before, but I think the ULN2003 Darlington transistor arrays are for driving the relays for the channel inputs. Texas Instruments actually specify those chips for use as a relay driver.

[@bobweiss8682]

Cable at 15:03 is power cable for the optional thermal printer, which installs in the top of the cabinet.

[@EEVblog]

@TheEPROM9 The cleaning didn't work I'm afraid, more troubleshoting will be required.

[@datahelg]

Dave, there is a built-in diagnostics/development menu that will list all of the calibration data and will tell you which areas are out of spec and what their values are. To access it (may or may not work for your scope, works on my 9310L scope and some others) press and hold the third soft-button (buttons next to the CRT) and while keeping it pressed, press the fourth then fifth buttons in rapid succession. This should bring up the development menu. It may take a few tries to get it.

[@rat4spd]

I used LeCroy in Grad school for mass spec. It was good for single shot capture of microsecond time samples. The floppy drive was a pain in the ass.

[@excavatoree]

I think this is the first CRT shown on the EEVBLOG.

[@joshstube]

Hey Dave! Can this be a regular part of your Blog? What if you were to buy some "parts only" items from eBay and attempt to fix them or at least finger the problem with them ??? I would think that your engineering background would suit you well for this sort of task, what do you say?

[@AlanGarfield]

HA that BT481 is a true colour RAMDAC I recognise. I wonder if they made a colour version.

[@RandyLott]

Are those board interconnects by Amphenol? I used to work there and those connectors looks quite familiar. I know there are dozens of manufacterers. They used similar connectors for jet's backplanes.

[@EEVblog]

@samgab Possibly! That's what you get when you close a door and your thumb is still in the door jam...

[@TheXGamer969]

Yay, fixed the aspect ratio of the video! Good job Dave!

[@joshstube]

Dave, another though on possible "repair videos", you could also let us take our cracks at it from the comment section! How about it!?!

[@uzimonkey]

Wow, what a complicated beast.

[@CampKohler]

@Vlakpage There are two ways the pins can make contact as good as soldering. One way is the have split springy pins that are forced into the vias. Another is to just push solid pins into slightly small holes such that there are four gas-tight joints made at the corners. Either has the advantage of easy assembly without the chance of solder bridges and it gives the possibility of connector replacement without having to get all those pins perfectly desoldered.

[@EEVblog]

@mckaymatts No, I don't have a cat, I hate cats!

[@giubin]

we can ear that you hate cats :D some experiment or "electronics" traps?

[@EEVblog]

@tubefella Put it on a trolley out in a production environment where it is wheeled around all the time, and then report back in a few months :->

[@MrDubje]

Cool scope, a very compact (crowded) power supply... to bad about the damage... I hope you can fix it. Those old memory sticks (EDO RAM?) don't have gold plated contacts, do they? I don't know if it is in relation with the problem (or part of it), but I would clean them anyway.

[@mckaymatts]

Is that a cat in the background? For your next review, cover your cat! (No teardown, please)

[@pret83]

Hi Dave. Do you plan som sort of tutorial, like your DC-DC converter tutorial? Teardown old devices is ok, but I think, the audience appreciate more some valuable content. Can you do some list of jelly-bean components (like voltage regulators, opamps etc.) and short description of them... ? I would appreciate it a lot. I'm a big van of you anyway. 

[@CampKohler]

@jerzmacow I like the flyovers. I can actually feel my brain analyzing everything like some kind of scanner shooting out laser beams. You can always skip over them. (Maybe Dave will sell a "flyover passifier;" when you suck on it, it outputs, "I LOVE it!" in his voice. :-) )

[@38911bytefree]

The scope got one of its ASICS removed in the wild way. I think it got a date with Mr Bin

[@CampKohler]

Do you suppose there is another 9384C somewhere in Sydney? If you could get together with another owner and you could swap modules until you find the problem. I wonder if there is a group (ham radio, etc.) in Aus that could find you another owner.

[@PhattyMo]

Those connectors on the SRAM boards and stuff aren't soldered? I'd probably start there,it's bound to be a minefield of bad connections!

[@chris1seto]

Is that a quadcopter in the background? Aeroquad if I'm not mistaken? ;)

[@mikedelectric]

Dave, when will you finish troubleshooting this Unit?

[@ZonaDixon]

odd that those TO-220 appear as though there are PTH for a heat sink, also out of curiosity do people outside of Canada ever encounter Robertson screws in devices?

[@beamfinder8336]

Nope, only the Chinese variety of nasty fasteners, and a lot of TORX- TR, which I like

[@perspectivex]

Any chance you can recommend a nice quiet fan with appropriate air flow, like you talk about at 14:25? I salvaged one of these scopes and agree the fan is super loud.

[@chrisridesbicycles]

The LeCroys are not that popular in our lab because they are bulky and loud. I alway thought the digital signal processing stuff is the reason for the power consumption but seems it is the RF frontend.

[@vaualbus]

On your blog you say that you have found the service manual. Where you get that? I need them for repair mine oscilloscope and I can't find that on iternet. If you can send me the link were you find it I will be vary happy. Alberto.

[@Photonface]

The coaxs are maybe delay lines?

[@thewii552]

ooh, nice. How did you manage to get this scope?

[@snipersquad100]

at 27 mins there a dodgy connected looking resister just right of the metal can above A14 on the silk screen

[@vaualbus]

You have said it could be power supply problem and at the end it is. The psu have destroy the 3.3V rail hybrid memory chip.

[@tagno25]

many of the .1 inch headers look like test points

[@jerzmacow]

I'm not a fan of the fly overs...it's weird to not hear you talking for more than 10 seconds

[@billynightmare]

Hi Dave, I have been looking into getting a Oscilloscope but the prices are way way above my budget atm, is there any Digital Oscilloscope I could use with my PC or even my arduino? could you recommend any software that will use my PC?

[@Cabose1fn]

my dad has been talking about how if he had an oscilloscope for every. what is a good brand/model to look for?

[@mccunecp]

you seem to know about alot about every thing I have a part number on a cap that I cant figure out they are nichicon caps. there are numbers below the NIchicon 12104 on one side of the negitive strip. and on the other side there is B K O CA1469 H 4 3 are all the numbers on the cap I have googled them and found nothing much. any ideas what voltage they are and the capacatances. I have 5 of them and they are of a nice size.

[@ddrl46]

Pretty sure that chip didn't exist when this scope was made.

[@EEVblog]

@gmaildotcom Obviously leakage from all the dust in the power supply. After it was cleaned out it now longer trips.

[@EEVblog]

@kiyotewolf Sagan, as in Carl Sagan.

[@bborkzilla]

At least it isn't running Windows NT like some Tektronix scopes of that era did!

[@excavatoree]

@excavatoree I forgot about the Tek scope. So, that makes this the second CRT. (but first raster-scan)

[@mccunecp]

I like to get one just to use.

[@vaualbus]

How did you pay for that oscilloscope at that time?

[@CampKohler]

@mckaymatts I wonder if that cat is named Sagan?

[@Burningmace]

Anyone else spot the oldskool TTL logic (74HC594) at 30:45? Made me chuckle.

[@vaualbus]

The others chip are probablyt demux for the memory.

[@teemune]

@jerzmacow Yeah. I thought I had my audio muted and had to rewind to check. >:(

[@vaualbus]

You found the problem?

[@Imryan19]

my grandpa works for lecroy

[@vaualbus]

where you buy the scope? How it cost?

[@dubbbear]

But can you play tetris on it ?

[@thewii552]

@fettfettmerafett now there is an idea...

[@neviemdopice]

26:33 BODGE!

[@psp10004]

27:50 well if my guess is as good as yours, i think that will be the atmega 2560 or 5120 chip (conspiracy)

[@jan.tichavsky]

@PhattyMo Yeah, I don't get how can all these pins get good connection without soldering.

[@ivanv754]

Oh wait, it's the same video! >: |

[@achemachew]

LOL, I'm not a fan of the floppy drives!

[@AlexForencich]

Nope, that would be FAR too slow. It's most likely some sort of custom ASIC or FPGA/CPLD to manage moving samples from the ADCs into memory at high speed.