LeCroy WaveRunner 606Zi starting only every Nth try

[0xdeadbeef]

I have a LeCroy WaveRunner 606Zi at my desk at work which recently became somewhat difficult to start. If you press the power button in OFF state, you can hear a faint clicking from inside the device but now the fans usually don't start and the scope doesn't boot (at all). If you press the power button for a few seconds in this state, you hear the faint clicking again (indicating that it tried to switch OFF the power supply).
At the moment, I have to repeat this several times until finally the fans start and the scope boots. It seems that starting happens randomly after N attempts, but N seems to get larger every day.
I figure the power button and the whole soft on/off mechanism is still working in principle (relay clicking), so it's probably a start issue of the power supply. I would assume that it's not a major problem as the scope works normally for hours when it finally decides to start. Maybe just a capacitor gone bad in the start circuit of the power supply or whatever.

This scope has a sibling which showed similar issues already some years ago and LeCroy gave us a cost estimate of ~2400€ as fixed rate for exchange of the power supply and calibration - which nobody was willing to pay even a few years ago. At this point, it's almost certain that the scope will be disposed of if I officially declare it defective. Also, it's a large company where equipment like this is never officially repaired in house and taking defective equipment from the waste container is considered theft and sufficient for instant dismissal. No discussions about this please. It's sad, but there is no way to change this.
Anyway, there might be a small chance to attempt an "unofficial" repair if it could be quickly done.

Which brings me to my actual question: is this a known issue for this series and if so: can it be repaired with minimum effort?

[joeqsmith]

From my own experience with old test equipment from LeCroy and HP, once that battery starts to fail, they will not power up.  I do not know why.   My WaveMaster behaves like that.   I am not sure with the WaveBlunder as I replaced the battery when I received it and I just dropped a new one in.   

Changing the battery on my 64Xi is a complete tear down.  Even with a zip gun and knowing what I am doing, it still takes me a fair bit of time. 

Posted a link recently of someone pulling theirs apart.  There's only one video on YT so easy enough to find.   You can see how much is involved.   Don't do what this guy does, no ESD mat, wrist strap, bags....  I was cringing while I watched. 

[figgie]

I have a WaveRunner HRO 66zi which is the same family. What OS is it running? What version of Xstream/MAUI?

The simple things you can try is take it apart and see if the large LVD connector (red cable) is straight in its socket. In mine it was slightly crooked and was causing all type of odd issues to include power on but no boot. It was also causing a degradation of the hard drive which corrupted a couple of sectors. The CMOS battery is easily accesible and replacable. You will note an issue with the battery when time starts to deviate from where it was set.

I got those corrupted sectors fixed before cloning and installing on a Corsair 1 TB SSD.

No issues with long term measurements (48 hours plus).

Outside of that, you are looking at sending it in to Lecroy unfortunatly.

[Kosmic]

I have a LeCroy WaveRunner 606Zi at my desk at work which recently became somewhat difficult to start. If you press the power button in OFF state, you can hear a faint clicking from inside the device but now the fans usually don't start and the scope doesn't boot (at all). If you press the power button for a few seconds in this state, you hear the faint clicking again (indicating that it tried to switch OFF the power supply).
At the moment, I have to repeat this several times until finally the fans start and the scope boots. It seems that starting happens randomly after N attempts, but N seems to get larger every day.
I figure the power button and the whole soft on/off mechanism is still working in principle (relay clicking), so it's probably a start issue of the power supply. I would assume that it's not a major problem as the scope works normally for hours when it finally decides to start. Maybe just a capacitor gone bad in the start circuit of the power supply or whatever.

This scope has a sibling which showed similar issues already some years ago and LeCroy gave us a cost estimate of ~2400€ as fixed rate for exchange of the power supply and calibration - which nobody was willing to pay even a few years ago. At this point, it's almost certain that the scope will be disposed of if I officially declare it defective. Also, it's a large company where equipment like this is never officially repaired in house and taking defective equipment from the waste container is considered theft and sufficient for instant dismissal. No discussions about this please. It's sad, but there is no way to change this.
Anyway, there might be a small chance to attempt an "unofficial" repair if it could be quickly done.

Which brings me to my actual question: is this a known issue for this series and if so: can it be repaired with minimum effort?

I would check the PSU. I had a WaveRunner 6100 doing something similar and I had to recap the whole PSU. I normally don't do shotgun replacement like that but in that case so many were faulty and venting that it was just simpler to replace them all.

The scope worked perfectly after that.

[Martin72]

LeCroy gave us a cost estimate of ~2400€

They always do this with older models, for our Wavesurfer 422 they also wanted a flat rate of around 2500€.
My tip is also C-Mos battery, then the power supply unit itself (electrolytic capacitors).

[tautech]

FWIW

Some years back I repaired a PC that had the same symptoms, many ON button presses before it would perform a boot.

Once opened and booted a PCB mobo cap was discovered so hot it very nearly burnt my finger.
All caps of the same style and value were replaced and PC went on to provide some years of further service.
YMMV

[0xdeadbeef]

For the record: the scope shows a correct time&date, so I figure the C-MOS battery can't be gone bad. And could a bad C-MOS battery really prevent the scope from powering up?
Again, if the scope doesn't start, there is the faint relay clicking, but nothing happens after that. No fan, no beep, the LCD stays totally black. I'd say there is no power supplied to the PC mainboard at all.
If the fans are starting, there is also a beep and the scope always fully starts without any kind of error message or otherwise uncommon behavior.
Again, to me it looks/sounds like "only" the soft-start of the power supply is partly broken, most probably because some capacitor involved there has lost its capacity to some degree.

[tunk]

Wouldn't really know - have you tested the relay itself?

[hpw]

From my own experience with old test equipment from LeCroy and HP, once that battery starts to fail, they will not power up.  I do not know why.   My WaveMaster behaves like that.

Yes, while this is not the LeCroy part, while simple the old PC main board behavior, with high internal chip clock & else current (dust) who drives the in sort time battery down to death.

If you power on this for ever, the battery will not show this issue. But who like that load fan noise 

 

[Martin72]

And could a bad C-MOS battery really prevent the scope from powering up?

Absolutely:

https://www.eevblog.com/forum/testgear/lecroy-hdo6034a-wont-boot-anymore-fixed/msg5180832/#msg5180832

[figgie]

For the record: the scope shows a correct time&date, so I figure the C-MOS battery can't be gone bad. And could a bad C-MOS battery really prevent the scope from powering up?
Again, if the scope doesn't start, there is the faint relay clicking, but nothing happens after that. No fan, no beep, the LCD stays totally black. I'd say there is no power supplied to the PC mainboard at all.
If the fans are starting, there is also a beep and the scope always fully starts without any kind of error message or otherwise uncommon behavior.
Again, to me it looks/sounds like "only" the soft-start of the power supply is partly broken, most probably because some capacitor involved there has lost its capacity to some degree.

Well it could also be the power on switch is worn since it is a contact based switch.
Power supply working and not working.. doubtful. Usually when a power supply on a PC goes, the issue is persistent since the caps cannot hold charge.

Now let me say one thing before you keep reading.

If the company is not yours, then the company has two options, fix it or buy new.

Do not waste to many cycles on Trouble shooting and repair as the company will not pay you the €2400 or anywhere close to that to fix it. If anything you get a good job and a pat on the back if you are lucky.


Since this is not yours and it is going to get trashed if it continues, i would disassemble and re-seat all the connections and change the CMOS battery regardless.

the Red LVD cable and the one ethernet cable. Also verify the SSD data cable is not bent so much that it broke (i replaced mine since i have SSD cables all over the place here).

I found in mine, the RJ45 port on the aquisition board, the contact pins were corroded (dull copper). a gentle filing to get them to be "shiney copper", reset the LVD connector flush and the problem went away.

The other thing you can do is clone the drive from magnetic to SSD. The power draw of SSD is less compared to the magnetic drive ( Lecroy supplied the WR series with Western Digital Black, 160 GB drive which the one that came with my WR66zi, pulls .58 Amps at 5VDC, this is average current.. start up current will be higher for a small time period).

SSD idles at .092 Amps (.46  Watts) with none of the inrush current of magnetic rotational media. Even at full tilt, max is .46 amps (2.3watts) while average is .4 amps (2 watts).

In the end, as an excercise for learning, yes but to save the company money. Don't as you will not get that split.

[nctnico]

I would not use a file on an RJ45 connector but use a bit of cardboard drenched in alcohol to remove dirt on the contacts. With a file you'll remove the contact plating and making matters worse as the underlying metal will easely corrode. RJ45 connectors are prone to developing contact issues over time. Especially when cheap (which is likely the kind Lecroy used).

[tautech]

For the record: the scope shows a correct time&date, so I figure the C-MOS battery can't be gone bad. And could a bad C-MOS battery really prevent the scope from powering up?
Again, if the scope doesn't start, there is the faint relay clicking, but nothing happens after that. No fan, no beep, the LCD stays totally black. I'd say there is no power supplied to the PC mainboard at all.
If the fans are starting, there is also a beep and the scope always fully starts without any kind of error message or otherwise uncommon behavior.
Again, to me it looks/sounds like "only" the soft-start of the power supply is partly broken, most probably because some capacitor involved there has lost its capacity to some degree.

Sounds exactly like the PC Mobo failure I described earlier.

The PSU Stnby supply not impacted.
Bad mobo caps and nothing more.

The PSU immediately goes into no start shutdown due to excessive current being drawn.
Cycled a few times it will finally latch and boot without issue.

[0xdeadbeef]

IMHO the power button itself can't be defective because there is an internal relay clicking audible when I press it - just nothing happens after that.

Also, I can't see how the C-MOS battery could be dead if I get the correct time&date when the scope finally boots up. Actually I had several PCs and also Windows based measurement equipment with dead C-MOS batteries in the past and they all complained about lost BIOS settings and showed some date in the 90s or so when they finally booted. The mixture of not not booting up at all but still keeping time&date doesn't sound like a C-MOS battery issue to me.

About excessive currents being drawn at start: I figure this scenario would make sense if the scope started after N successive start trials with short time between. This is not the case though.
As explained before, the scope has some kind of soft on/off feature. As it was still working OK, the behavior was as follows:
- If the power button was pressed in OFF state, an internal relay would click with a few hundred milliseconds delay, then the fans would start, a beep from the BIOS start could be heard and the scope would boot
- If the power button was pressed (shortly) in ON state, this would send a shutdown request to Windows and the scope would shut down Windows and then switch OFF
- If the power button was pressed a few seconds in ON state, it would switch off the scope immediately without shutting down Windows. Actually, I never did this for obvious reasons while the scope was working
If the scope is not booting up now, I can still switch the relay with a short press in OFF state, but then I need to press it for some seconds to hear it clicking again.
So one ON/OFF trial needs several seconds. Also, I didn't get the impression that trying to switch it on immediately after the last long press doesn't increase the chance that the scope starts.
As I said before, it seems to be somewhat random if the scope decides to boot or not. Sometimes it boots even if the last trial was half an hour ago.

[tautech]

If it's not bad mobo caps then the power ON button might have a debounce issue. Scope it.

Membrane button ?
It might need cleaning or the conductive part is stuffed.

[0xdeadbeef]

The button is working as before. The relay is clicking is as before. Just the main power and fans are not starting after the relay clicking.

[Martin72]

The mixture of not not booting up at all but still keeping time&date doesn't sound like a C-MOS battery issue to me.

Did you measure the battery voltage?
Anything below 3V, even 2.95, is suspicious.

[Kosmic]

I would still put my money on a bad capacitor in the PSU.

The problem is you probably need to disassemble the whole thing to reach the PSU.

Personally, in your situation, I would simply declare it broken and let the company do what they do with broken stuff. Unfortunate if it get destroyed 

[tautech]

The button is working as before. The relay is clicking is as before. Just the main power and fans are not starting after the relay clicking.

Ok at least behaviour is consistent.

A bad mobo cap will send the PSU into instant shutdown or there's a bad cap in the PSU.

[0xdeadbeef]

I would still put my money on a bad capacitor in the PSU.

This would be also my assumption. I kinda hoped that someone here would have observed the exact same behavior, repaired it successfully and could give feedback how much effort it was.

Personally, in your situation, I would simply declare it broken and let the company do what they do with broken stuff. Unfortunate if it get destroyed 

Ten years ago, this would have been a valid plan. Today, this will leave me with no scope or a much worse scope "borrowed" from somewhere. But I definitely wouldn't get a new scope or even a comparable one at my bench. Actually, it's rather clear that sooner or later I won't have my own bench anymore next to my desk but need to share it with colleagues who come to the office only once a week or so.
Sad times for engineering.

[Martin72]

If it's not the battery, you could look at the outputs from the internal power supply with a scope.
Whether a line sags during startup or generally has too much ripple, both of which indicate a defective capacitor.

[tooki]

I can say with nearly 100% certainty that it’s the power supply: at work, in another department I used to work in, my former coworker has repaired 3 or 4 LeCroys with that exact problem, including his 606Zi and the 8254M on my bench. (Thats 3 or 4 out of 5 units I’m aware of.) IIRC, it’s the 5V standby rail that fails. It manifests as intermittent failure to boot, with the failure rate increasing until becomes unable to boot at all. The fix is to replace a few bulged capacitors on the PSU board. At least in the units we saw, the bulging was fairly obvious, at least compared to all the non-bulged caps on the same board.

I told our LeCroy rep that I consider it very questionable that they installed cheap (Capxon, IIRC) caps on devices in this price range, where I consider it an absolutely reasonable expectation for them to use only top-quality parts. Penny pinching a few bucks of caps on a high-markup $10K+ device is ridiculous.

So:

Which brings me to my actual question: is this a known issue for this series and if so: can it be repaired with minimum effort?

Yes and absolutely.

Figuring out how to gain access to the power supply board actually takes more time than replacing the caps, because of the 606Zi’s weird front panel. My former coworker said he found instructions online somewhere showing how to open it, so look for that rather than wasting time trying to figure it out yourself.

[Kosmic]

@0xdeadbeef if you end up opening the PSU make sure you have a ESR / LCR meter at hand. Worth testing capacitors even if they physically look good.

[0xdeadbeef]

I just found this Chinese teardown/repair and indeed it looks like a PITA to get the power module out...
https://www.sy2k.com/2018/lecroy-waverunner-610zi-teardown-repair/
And, there's this video as well:
https://www.youtube.com/watch?app=desktop&v=q-bKj7J1fM4