LeCroy WaveSurfer 454 noise? - Page 1
Forum section: electronics / testgear

author: ARF
author_rank: Regular Contributor
timestamp: December 16, 2022, 08:34:21 pm
content: Hi guys!I bought this oscilloscope and I do not like the picture on the screen. The line turns out to be very thick, full of some noise. This is fine?Moreover, in some scanning modes, the line does not reach the end of the screen - this is some very strange defect. I did a factory reset and it didn't change anything.I took screenshots- built-in calibration signal and the sweep reaches the end of the screen.- built-in calibration signal and the sweep does NOT reach the end of the screen.- maximum gain (input shorted to ground)- minimum gain (input shorted to ground)

author: Martin72
author_rank: Super Contributor
timestamp: December 16, 2022, 09:14:26 pm
content: Hi,Actually I got a WS422 here, so I could directly compare it to your scope pics.Noise seems to be the same - and reduced when using bandwithlimit, and more reduced with Eres.Edit1: Pics wil not be posted in the order I´ve uploaded them....why...Edit2:QuoteHave you checked the timebase/acquistion settings ?

author: james_s
author_rank: Super Contributor
timestamp: December 16, 2022, 09:19:03 pm
content: Are you sure the noise is not actually there? DSO traces tend to look a bit noisy because they let you see noise that an analog scope doesn't display.

author: ARF
author_rank: Regular Contributor
timestamp: December 16, 2022, 09:37:24 pm
content: Yes, indeed a direct copy. I have owned an Agilent Infiniium 54832D for a long time and it works differently, the image is much cleaner.I already managed to disassemble this LeCroy a little. I noticed that cheap SMD aluminum capacitors are used on all boards (tantalum capacitors are everywhere in Agilent, except for the processor board and power supply), I noticed that a couple of capacitors have already swollen on the processor board (they are high quality, but worn out).Either it works like that at all, or the capacitors have degraded, but our oscilloscopes have an identical picture. Weird...By the way, since you own your LeCroy for a long time. Have you upgraded the processor, memory and SSD yet? I noticed that the motherboard is made on the basis of VIA CLE266, which means that we can install Tualatin-S (512K cache!!) up to 1.4GHz, which is much better than the regular Celeron Coppermine 850MHz. I also have 512MB of memory installed, but the motherboard must support up to 2GB.Have you done any other upgrades? Maybe you can unlock some options, update software, BIOS or something else?I don't understand what can be configured...

author: Martin72
author_rank: Super Contributor
timestamp: December 16, 2022, 09:46:32 pm
content: QuoteCould have to do with the amount of memory.QuoteThe scope I got since appx 3 weeks, before I´ve used it from time to time in the last 16yrs at work - We´ve sorted it out and I took it to home..It needs some cleaning, fan exchange, and randomly a failure appears that I want to fix.Then looking for hardware tuning..Quote2 weeks ago I´ve unlocked the advanced trigger package, math package also....

author: Martin72
author_rank: Super Contributor
timestamp: December 16, 2022, 09:49:51 pm
content: QuoteSee the pics, you don´t have "more" in the menus as my 422.It seems your model have more memorypoints.The thing with the trace that won´t last over the whole screen I saw on our Waverunner, as in the menu the settings in the memory management was changed by someone.EDIT:My thread:https://www.eevblog.com/forum/testgear/lecroy-ws422-strange-behaviour/msg4560139/#msg4560139

author: ARF
author_rank: Regular Contributor
timestamp: December 16, 2022, 10:19:59 pm
content: You were right, I switched the "Max Sample Points" to 1.00 MS and the problem was solved.Perhaps this is due to the installed option "VL" - sample memory increase.It is very strange that this configuration did not reset to default, although I did a factory reset.I'll follow your thread... I'm really concerned about the SMD aluminum capacitors in this oscilloscope. I have come across such capacitors in the Advantest spectrum analyzer and network analyzer. These devices were 95-97 years. So, all(the most of) aluminum through hole low-esr capacitors were OK, but these SMDs are completely dead (especially those that are less than 100uF). I think that this is due to the fact that the through hole capacitors were designed for high ripple currents and 105С, and the SMDs were "general purpose". If you have an LCR meter, desolder a few 10uF and measure them.Unfortunately, now I am in hostile territory, without my equipment and without the ability to quickly and easily buy electronic components. So I think you will be the first to get some good results.

author: Martin72
author_rank: Super Contributor
timestamp: December 16, 2022, 10:24:52 pm
content: QuoteQuoteAha...this I don´t have, interesting..QuoteActually I´m repairing a hioki lcr meter (5Mhz), then the scope will be the very next - I think on the next weekend I´ll contiue examining/repairing.

author: ARF
author_rank: Regular Contributor
timestamp: December 16, 2022, 10:27:52 pm
content: I am waiting for HIOKI 3532 for my new residence, but it won't be soon(

author: Martin72
author_rank: Super Contributor
timestamp: December 16, 2022, 10:30:34 pm
content: Ha, a 3532-50 is what I got...See repair section..

author: ARF
author_rank: Regular Contributor
timestamp: December 16, 2022, 10:41:08 pm
content: Good choice!Be sure to make a complete copy of your hard drive. I've read other threads, guys say that the second partition of the disk contains some kind of calibration settings that can only be restored by an official service center.