Lecroy WS422 strange behaviour - Page 1
Forum section: electronics / testgear

author: Martin72
author_rank: Super Contributor
timestamp: December 03, 2022, 09:44:34 pm
content: Hi,This scope we don´t want to repair because only for having a first look on it, lecroy want to have more than 2 sds2104x+ will cost together..But I take a look...So what´s wrong ?First it seems nothing, you can power it on ( looooong boot time...) and it´s doing what you expect it should do.But sometimes or better more and more, after booting one or both channels are "freaking out".The "noise" are filling the whole screen then, regardless of the voltage/div or if you switch to GND.I´ve got a feeling this is more than simple contact problems because:Example from a hour ago, Ch1 is noisy as described so I swithed it off, turn ch2 on.It shows a distorted waveform(bodnar connected) which becomes clear when you switch the "noisy" ch1 on...But in this scenario scope won´t do measures, the values are randomly.So....Turn it off.Then on again and if you have luck, everything is fine....This would be an interesting project to find out what´s going on, I´ll report it here step by step.But if anyone here got the same issue before or knows from it, tell it here....Want to fix it, it´s a nice scope to have together with my 12-bit.But as I said above, this sounds not easy...But that would be a little bit boring when not.Martin

author: tautech
author_rank: Super Contributor
timestamp: December 04, 2022, 12:48:08 am
content: Older scope might need recapping so KISS and first check PSU rails for ripple then any on-board converters too.

author: nctnico
author_rank: Super Contributor
timestamp: December 04, 2022, 12:52:00 am
content: Checking the PSU for capacitors with bulges and smelling like cat wee is a first good step. A second step is to reseat all boards and connectors. This could be a contact problem somewere.

author: Martin72
author_rank: Super Contributor
timestamp: December 04, 2022, 01:12:10 am
content: Yepp, you´re both right.Concerning contacts, as this scope were often worldwide on travel for service, the "graphic card" was often loosen it´s contact, so one of my first tasks at work as a beginner here (2005) was to fix the card with a self build holder...Took the scope apart a few hours ago, waste amount of dust in it, fans are loudly, CPU cooler is dusty...I´ll make a total cleaning up, then looking further, visible quality control...The building quality is remarkable good, no wonder because it´s from iwatsu.Looks like a small PC with some additional parts...

author: Martin72
author_rank: Super Contributor
timestamp: December 04, 2022, 12:03:47 pm
content: This is building quality...Maybe I got a little bit time today to tear it down further, let´s see.

author: nctnico
author_rank: Super Contributor
timestamp: December 04, 2022, 12:34:53 pm
content: If the build quality of a piece of Lecroy branded equipment is high, then it is a rebrand.

author: Martin72
author_rank: Super Contributor
timestamp: December 04, 2022, 01:01:38 pm
content: Shoot !

author: egonotto
author_rank: Super Contributor
timestamp: December 04, 2022, 02:49:54 pm
content: Hello,have you the service manual?Best regardsegonotto

author: tv84
author_rank: Super Contributor
timestamp: December 04, 2022, 03:07:44 pm
content: Quote from: egonotto on December 04, 2022, 02:49:54 pmHere.

author: Martin72
author_rank: Super Contributor
timestamp: December 04, 2022, 03:31:54 pm
content: Now I got it !

author: coromonadalix
author_rank: Super Contributor
timestamp: December 04, 2022, 05:35:31 pm
content: before going too far i would make asap a drive backup just in case .....

author: Martin72
author_rank: Super Contributor
timestamp: December 04, 2022, 08:53:00 pm
content: The service manual is very informative, every SM should be in this way...Wish I would have my holidays now...

author: darkstar49
author_rank: Frequent Contributor
timestamp: December 06, 2022, 02:53:43 pm
content: In fact, I'm even surprised they provided no schematics in the SM, as opposed to the one for the (non -A) WR6K...?Or is this a crippled version ? Or linked to some Iwatsu copyrights ?

author: Martin72
author_rank: Super Contributor
timestamp: December 16, 2022, 11:25:50 pm
content: Quote from: coromonadalix on December 04, 2022, 05:35:31 pmI´m thinking about to use a usb stick for it, this should be OK or ?

author: RedCali
author_rank: Contributor
timestamp: December 17, 2022, 08:18:56 am
content: Quote from: Martin72 on December 16, 2022, 11:25:50 pmThe most important thing to have a Backup is the calibration data - stored unter D: in a hidden folder, cause if that get lost you have to send it to lecroy and thats quite expensive....You can as well make a raw copy off the drive:http://www.runtime.org/driveimage-xml.htmNo matter where to stored - just be sure you have it :-)