Repair Lecroy Waverunner 104MXi

[aryajur]

Hi,
I am trying to repair a Lecroy Waverunner 104MXi. The problem is when you plug it in and switch it ON, windows starts booting but then it just turns off. Now if I try to switch the oscilloscope ON again then it does not work until and unplug it and plug it back in again.
I wanted to look at the power supply so I started to open it. I am stuck and not able to figure out how to open it to reach the power supply module. I have attached pictures showing where I have reached up till now.
The problem is that the power supply is on the back side of the scope. And there is no way to open it. I have to get to it from the front by opening and removing what I can. But now I can't seem to get any further. The screws are inaccessible to open the next board. It seems it would have been helpful if I was able to flatten the sides of the case. But they are seem to be stuck to the adjacent sides.

Any suggestions or help would be greatly appreciated.

Thanks,
Milind

[aryajur]

Some more images

[crossan]

You need to remove the acquisition board and ideally the cpu board before you can get to it.
The PSU is the last thing you can remove from that damn box 

I can supply pictures if you like.

[veiko]

Did you ever get it fixed? I've got the same problem on my 44Xi, and I've got no clue what's wrong with it. The caps all look ok.

[smaultre]

my friends i need high quality photos of asic boards, and inputs attenuators trying to increase the bandwidth. 104, 204 models.

[darkstar49]

Same here... 64Xi starting for a few seconds, then shuts off... definitely a PSU issue (unless the acq board tells the PSU to shutdown, but I don't think so...)
Can only confirm what was already said, everything must get out before getting to the PSU, but it's not that much... looks a bit complicated the first time, but there are basically only 3 pieces to get there: the front-panel, the acq board (together with the FE's) and the CPU board.

Several people already had issues with the Xi/Xs (and all derivates, Xs-A/B, Xi-A...) PSU, but (almost) none documented their fix so far...

[darkstar49]

my friends i need high quality photos of asic boards, and inputs attenuators trying to increase the bandwidth. 104, 204 models.

Hope you'll get some info here, but I guess it's rather unlikely... the FE part is screwed to the acq board, and I guess very few people will need to disassemble the FE part on these units (which is slightly different for each bandwidth), most interventions are linked to the front-panel (broken encoders, broken plastic struts, touch-screen replacement,...) or to the CPU board...

Many people digged into the matter of increasing the bandwidth of their LeCroy scope, but I've not heard of any being successful... 

[smaultre]

Hello Darkstar, thank you for reply!  I'm sure that the mainboards is identical with 204Xi
Over quick view on inside, there are some smd capacitors on differential lines maybe some of they limits the bandwidth.
And maybe, upgrade the CPU,memory or whole PC-motherboard...


Did you allready repair your 64xi?  Their PSU works in wery "hot mode".

[darkstar49]

Hello Darkstar, thank you for reply!  I'm sure that the mainboards is identical with 204Xi
Over quick view on inside, there are some smd capacitors on differential lines maybe some of they limits the bandwidth.
And maybe, upgrade the CPU,memory or whole PC-motherboard...


Did you allready repair your 64xi?  Their PSU works in wery "hot mode".

The story with the FE seems a bit complex... the early suit-case models with PS2 connectors (but with L-BUS) have a certain board for the 44 & 64 models, and a different one for the 104 & 204 models (you can see it with the power button, which is narrower on the 104 & 204). Although the 64 has the ability to multiplex ADCs, but I don't know whether there are differences at board level or not. For the latest Xi-A and Xs-B models (te black ones without PS/2 connectors), the FE board has the same size for all models, but I don't know what differences at board level.

But while my belief until now was that the acq boards were identical (across bandwidth), that of my MXi-A (without PS/2 connectors) has a 400MHz label on it. Until now, I'd not noticed any differences between those acq boards (already had everything from 44 to 204), but I have to admit that I didn't check thoroughly.

Anyway, the internal setup of the recent 44MXi-A is significantly different from everything I'd seen so far, the only common parts are the PSU, and the front-panel assembly (apart from the hdd, which is now mounted with a 30° inclination, and has a large plastic protective cover)

I'm just busy with that one, yet another dead PSU (no reaction at all...), I'll take pics, but it is unbelievably dirty (never saw this in my entire life...), so some serious cleanup is required first.

Apart from that I've got 3 other Xi's with dead PSU's, and symptoms range from no reaction at all to a scope that runs but shuts off randomly... can't identity common symptoms on those failing PSU's so far.

I just opened one of the other Xi's PSU (the Cherokee/Lineage Power SP651-Y03A/Y05A, depending on the generation), one that does start, but shuts off after a few seconds, it doesn't have time to get to the Windows boot process. Nothing obvious to be seen inside the PSU.

I'm pretty sure also that those PSU's interact with the acq board... the acq board actually gives the 'go' signal for the PSU to complete startup, so that last symptom could eventually indicate a problem on the acq board (although I think it should shut off quicker in that case ??), but I've no clue where to look, as there's no documentation whatsoever
For now, I'll assume that the issue is with the PSU alone. I'll setup a test bench with some dummy loads, given that I have 4 of these failing PSU's, I guess that time isn't spilled...

[smaultre]

Sure! yes, now i see its really asiq. differents.

Trying to add option key make a with ffffffff mask
I bricked it, now after serial of warning/error screens, its says "DSO crash" then close the DSO application.
How can i remove this bad key entry? Only by re programming the flash?

[darkstar49]

Yes... got to clean the eeprom... I don’t say no one on Earth has alternate ways for doing that, but that’s the most obvious one... already discussed in another thread in the Test Equipment forum.

[dominitech]

I was able to fix a couple LeCroy scopes with this very issue and one of them was for a WS44Xs-A.  I found the 3V coin battery was very low on CPU mobo.  I replaced it but still had boot up problems.  Errors were reported with the Hard drive.  I upgraded the Hard drive to an SSD cloning everything onto it.  I booted into BIOS and disabled the 32 bit data transfer rate setting.  It booted up most of the time but intermittently crashed due to having bad data from original hard drive.  I used the Acronis recovery utility to restore the XP embedded OS and no more boot up and crashing problems.  Unit was working normally after that.  Make sure to back up any calibration data just in case.  Hope this helps.

[aryajur]

Did you ever get it fixed? I've got the same problem on my 44Xi, and I've got no clue what's wrong with it. The caps all look ok.

Sorry for the silence. I got busy with other stuff and it was sitting on my desk for a long time. Now I have got back to it. Its still not fixed. Will try out things in this post.
Couple of updates though were that I was able to get the Manuals from Lecroy and able to follow them and open up the whole thing. I did record a video of some part of opening it, I hope I can put it back again now that all the time has passed and there are so many different types of screws. Anyway will try it.

[crossan]

I'm having similar problems with my 104Mxi, you mention manuals from Lecroy? I have not seen these where would I find them?

[GertKruger]

I managed to fix a LeCroy WaveSurfer 44MXS-B. https://www.eevblog.com/forum/repair/lecroy-power-supply-(cherokee-lineage-power-sp651)/msg4876079/#msg4876079

[RamboChen]

I have got a similar problem, The system will experience random crashes, but the bios don't prompt any recovery tool notification, so i can't recovery it. Even if I start-up using WinPE(with U-disk), it's still crash. is there have a hardware problem?