LeCroy WaveAce 1012 Scope Issues - Page 1
Forum section: electronics / repair

author: btmerchant
author_rank: Newbie
timestamp: September 27, 2017, 10:25:24 pm
content: I have a WaveAce 1012 that worked great till one day I was probing some digital logic and pressed the "Auto" button and the thing went Dead! since it is out of warranty I have done been looking into it.The power supply primary has 178V DC but no secondary output, not sure if it is enabled by the system etc.Any advice would be greatly appreciated. If anyone has Schematics of at least the power supply it would be awesome...

author: Toasty
author_rank: Regular Contributor
timestamp: September 28, 2017, 02:06:25 am
content: Can you upload nice clear photos of the power supply board? Top & bottom?I'm not finding any service manuals online.T

author: tautech
author_rank: Super Contributor
timestamp: September 28, 2017, 02:28:09 am
content: Quote from: btmerchant on September 27, 2017, 10:25:24 pmIIRC they are rebranded Siglent SDS1102CN or M L. (L for 7" display) N= 40Kpts, M= 2 Mpts memory.The service guide is here:http://www.siglent.com/Uploadfile/file/20140925/SDS1000CNL_ServiceManual_en.pdf

author: btmerchant
author_rank: Newbie
timestamp: September 29, 2017, 01:11:03 am
content: Here is a link to a folder containing all the info I currently have (including the requested pics)https://www.dropbox.com/sh/uoizkpem2v435m2/AACWifWODF462qmx-KEHqLH1a?dl=0So far I have good primary voltage to the switch witch is actually an integrated control/FET (TOP246YN) and I replaced it a while back (No Change)I can find no shorts in the output section, I tested both opto couplers out of circuit (good) the secondary gets a pulse but after the diode it is a mere blip.I am not very experienced fixing Switch Mode Supply's in my world they are cheaper to replace than to fix,but in this case, well anyone have a good one for sale?Well thats all I have so far...Thanks for the help

author: Toasty
author_rank: Regular Contributor
timestamp: September 29, 2017, 03:04:56 am
content: Is it ticking by any chance?Check the output MOSFETs and diodes. In circuit is fine using the Diode Check mode on your DMM.The small caps are my usual suspects, but these are all Rubycon. Worth a check if you have an ESR meter.T

author: tautech
author_rank: Super Contributor
timestamp: September 29, 2017, 08:45:43 am
content: Working from this datasheet for the Mosfet/controller combo:http://www.farnell.com/datasheets/26251.pdfYour unit should have a mechanical mains switch so any configuration parameters for the controller are likely only to be soft start. Read the bit about fault conditions in Shutdown/Auto-Restart on P9.Looking at the typical usage circuits from P20 on we see the divider and dropper from HV DC are 1/2 W which suggests they are under a little stress and if they drift wildly it'll upset the input into pin X. The dropper into pin L need be checked too.Further to those mentioned the series diode between the secondary and the opto need be checked along with the main polarised cap, in all examples shown as 47uF that indicates it's for bulk storage for the C pin.Another possibility is the other smoothing polarised cap before the opto or the ceramic between C and ground(if fitted).Failing all those you'd look hard at the secondary side LV diodes and caps IF there is not a short on the mainboard that's pulling the rails down and putting the PSU into External current limit mode.One of the rails from the PSU is only mains Line reference for the Trigger....work out which one it is and exclude it from investigations....it won't be affecting the PSU startup.Spend some time reading this datasheet to understand it fully and work your way through sections of the PSU circuit, eliminating them as suspect as you go.Tip. The feedback circuit will be on probably only one of the rails....concentrate on that rail initially.Oh, and the PSU section in the linked Siglent service manual is on P46.Good luck.