Products > Test Equipment

LeCroy WaveRunner 606Zi starting only every Nth try

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figgie:

--- Quote from: 0xdeadbeef on April 18, 2024, 03:56:43 pm ---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.

--- End quote ---

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:

--- Quote from: 0xdeadbeef on April 18, 2024, 03:56:43 pm ---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.

--- End quote ---
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.

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