Digitech QC1934 Digital Storage Oscillosope - Page 1
Forum section: electronics / testgear

author: Lango1818
author_rank: Contributor
timestamp: April 02, 2020, 12:53:41 am
content: Hi everyone, one of the best sites on the web.My first post so here goes.I have just been given a DIGITECH QC1934 DSO. However on power up the splash screen said it is a Siglent 110 CNL, and although the trace comes up the entire screen is covered in noise. I have tried "Do Self Cal" button to no avail.When I go to the System Status screen it has the following.Startup Times - 74, Software version - 6-41-2.50, Product Type SDS1102CNL,Serial No NEU00001120789.When I pulled the scope apart, it is indeed a Siglent, with the number CA_M_110300 and SAT7.820.681k printed on the main board. The scope appears to be bricked, I have been on to the Siglent web site and downloaded the SDS11002CNL firmware. The scope appeared to load but no use the scope is still malfunctioning.It would be nice to be able to somehow reset the firmware and make it work as the condition of the scope is like new and the screen is much larger than my Rigol. Any suggestions greatly appreciated before I disassemble the scope for a few parts.Kind Regards Jeff

author: tautech
author_rank: Super Contributor
timestamp: April 02, 2020, 02:07:54 am
content: First try carefully reseating the display ribbon cable. Check the silvered ends for corrosion and gently clean them with an eraser if necessary.There should be one for the front panel and a larger/wider one for the display.Then IIRC it terminates to another connector that interfaces with the display cabling. That is a good bit harder to get to as you need remove the mainboard at least to access it.The CNL service manual might be of assistance:https://siglentna.com/download/2710/AFAICT you have installed the latest (and last) CNL firmware before they were updated to CNL+ models.It's fine so leave it there. I will have other old CNL firmware in archives.

author: Muttley Snickers
author_rank: Unknown
timestamp: April 02, 2020, 06:33:40 am
content: I did some basic research on these scopes once and always thought that the Digitech QC-1934 was in fact a Siglent SDS-1102 CML and not a CNL model. Tautech is in a better position to verify one way or another and confirm if this particular model has been flashed with the correct firmware version.

author: tautech
author_rank: Super Contributor
timestamp: April 02, 2020, 07:16:31 am
content: Quote from: Muttley Snickers on April 02, 2020, 06:33:40 amScratch, dig, scratch......Jaycar catalogue 2015 Pt# QC1934....Mem depth = 2 Mpts = CML model.Good catch Muttley !Yes wrong FW installed......scratch, click, click > CML FW folder.Attached.... ...V32 .rar.txt......Remove .txt extension then unpack the .rar file and follow instruction in the Readme file.If it does not install you may need to run this .cfg file first to configure the DSO to accept the firmware.....also attached as .zip file. Unzip.

author: Lango1818
author_rank: Contributor
timestamp: April 03, 2020, 02:45:23 am
content: Thanks for your reply, tried suggestion and DSO still a brick, worth a try though.Thanks for the link to the service manual too.

author: Lango1818
author_rank: Contributor
timestamp: April 03, 2020, 02:51:43 am
content: Where can I find these cfg files please.

author: tautech
author_rank: Super Contributor
timestamp: April 03, 2020, 04:09:26 am
content: Quote from: Lango1818 on April 03, 2020, 02:51:43 amThe zip attachment. Unzip it.

author: Lango1818
author_rank: Contributor
timestamp: April 03, 2020, 05:02:25 am
content: Thanks for all your help, but still no luck. However I noticed that if I set the coupling on both channels to ground all of the noise goes away. Maybe something in the front end(Relay?) is not switching the circuit on AC and DC coupling in, and the front end is not terminated correctly to the BNC connectors and hence the noise???

author: tautech
author_rank: Super Contributor
timestamp: April 03, 2020, 06:30:39 am
content: Quote from: Lango1818 on April 03, 2020, 05:02:25 amWhat does the System info say now ?Did you run the .cfg file then the FW update (.ads file) ?QuoteSo you get 2 flat traces that you can move around with the vertical position controls ?This could be good news in that the signal path is just open as you surmise but how and why ?Are there any clues as to what has happened from the previous owner ?

author: Lango1818
author_rank: Contributor
timestamp: April 03, 2020, 07:07:18 am
content: The System info is the same as before.I did run the .cfg file then the FW updates a couple of times and the "do self cal".Correct I now get 2 flat traces that I can move around with the vertical position controls when I set the coupling on both inputs to ground.No clues as to what has happened from the previous owner.Thanks again for your good advice and pointers.

author: tautech
author_rank: Super Contributor
timestamp: April 03, 2020, 07:25:00 am
content: Quote from: Lango1818 on April 03, 2020, 07:07:18 amHmmm, I'll have a hunt for another cfg file and one that specifically states it's a CML one.QuoteThe Self Cal won't be needed until we get the SYS info correct and the display fuzz gone.QuoteI dunno if we have a HW fault or the FW is just wrong however my suspicion is the previous owner installed the wrong FW as is identified in you OP. Let's concentrate on only getting it rightly configured as a CML and see what happens then.I'm sure there's other threads about these issues of wrong FW used but they escape my memory ATM.

author: tautech
author_rank: Super Contributor
timestamp: April 03, 2020, 10:29:21 am
content: For completeness sake you might wanna follow the display ribbon cable problems in this thread:https://www.eevblog.com/forum/repair/repair-siglent-sds1102dl/

author: tautech
author_rank: Super Contributor
timestamp: April 04, 2020, 07:29:44 am
content: CML cfg file in this post:https://www.eevblog.com/forum/testgear/atten-ads1102cal/msg2536032/#msg2536032

author: Lango1818
author_rank: Contributor
timestamp: April 04, 2020, 07:15:17 pm
content: I had been searching the net and stumbled across a Russian website myself. The file I downloaded seems to be identical to the file on the EEV forum, but I tried the .cfg file from Skullkill's post in case there is some difference. Currently with the file I found on the Russian web site and the file from Skullkill,s post, the scope is still a brick but with a CML splash screen and System status saying it is a CML as well.I noticed that there is no AC output on the 1 Khz probe adjust terminal but has a DC voltage of 1.619 volts. Another strange thing is when I push the default setup button, only channel 1 is in operation. I would have thought that default setup would have both channels operational. As mentioned earlier, with both channel inputs set to ground the screen is crystal clear and all menu buttons appear on the display and the position controls move the trace up and down.System Status is now.Software Version: 5.01.02.32Hardware Version: 6-41-01Product Type: SDS1102CMLSerialNo.: NEU00001120789I guess the NEU at the start of the serial number as opposed to ADS on Skullkill's post is because my scope is a Siglent re-bagged as a Jaycar??Just to try something else I dropped the firmware back to 5.01.02.29 and I noticed the hardware version had changed in system status to 6-42-2.5 is this normal for the hardware version number to change?I will hold off from scrapping the scope for the moment and might drop a Email to Siglent to see if I get any joy there.I was wondering if it is possible to reboot/reset the firmware somehow via the serial port.As always your replies are greatly appreciated.

author: tautech
author_rank: Super Contributor
timestamp: April 04, 2020, 07:55:38 pm
content: Quote from: Lango1818 on April 04, 2020, 07:15:17 pmOK well at least that's some progress.QuoteThat's worrying as it should be 1 KHz 3V p-p squarewave.QuoteThat's normal for these DSO's.QuoteYep this requires further investigation.QuoteYes all this looks fine.QuoteThey won't offer help as it's a rebadged product and now Jaycar don't sell these I doubt they or their distribution company Electus will either.QuoteNope, I think we have the SW structure as it should be but the missing probe compensation signal worries me as it might indicate a HW fault. So for now use the CNL service manual I linked earlier and work through the fault finding section in which you need a DMM and another 100 MHz scope to check all the test points.The one other avenue I need to research more is if there was a different FW series used in early CML versions, like a 3.*.*.*.

author: Muttley Snickers
author_rank: Unknown
timestamp: April 04, 2020, 11:37:26 pm
content: Another member also had problems with suspected noise on the inputs and an image in their second post matches what the member here is seeing, this member is still active so it might be worth sending them a message and asking if the issue was ever resolved.https://www.eevblog.com/forum/beginners/atten-oscilloscope-firmware/msg1060220/#msg1060220https://www.eevblog.com/forum/beginners/atten-oscilloscope-firmware/msg1060464/#msg1060464

author: tv84
author_rank: Super Contributor
timestamp: July 05, 2020, 08:22:45 am
content: I'm also doing some contribution in this thread:https://www.eevblog.com/forum/testgear/atten-lt-gt-siglent-conversionscrossflashes-do-you-still-have-problems/msg3049442/#msg3049442Follow that.The last digits of HW version are the "FPGA version". They could change depending on the FPGA contents and/or CPLD.Another member has precisely this same problem.Maybe Lango1818 should flash my FW version that includes the FPGA contents to see if there is any change.Another venue is to try to change the S/N to some Siglent format in order to check if the FW does some settings based on that.

author: tv84
author_rank: Super Contributor
timestamp: July 05, 2020, 09:33:15 am
content: Quote from: Lango1818 on April 02, 2020, 12:53:41 amLango,(That is the result of having flashed the Siglent FW in the Digitech (Atten).)As you have discovered you have the equivalent of a Siglent CML as you can see in your photo, you have the additional SRAM soldered.My 1st advice, to see how it behaves, is to flash this ATTEN_ADS1000CAL_3.01.01.31R16_ProdId_79_ISP. Look here:https://www.eevblog.com/forum/testgear/atten-lt-gt-siglent-conversionscrossflashes-do-you-still-have-problems/msg3049442/#msg3049442That would return the scope to an Atten. Based on your S/N it looks like it's an Atten.It downgrades the FW but might solve the traces problem. If it solves the problem you can flash the Atten CAL .CFG file.