RIGOL MSO1104Z MSO problems - Page 1
Forum section: electronics / testgear

author: Tangent_Tracker
author_rank: Regular Contributor
timestamp: April 03, 2018, 10:27:59 am
content: Does anyone else use this scope with the 16 channel MSO? We got ours new last year and very quickly had problems with the logic analyzer. Signals became unpredictable and it would fail to calibrate. After talking to Rigol, and sending the analyzer back, then the oscilloscope, the problem seemed to be fixed. I will say at this time we were told not, under any circumstances to remove the module when under power, as this can cause damage to the board! We had not actually done this, but it struck me that a piece of equipment in a lab environment like this is very poorly designed if you have to power cycle the scope every time you connect or disconnect a bit of equipment that handles low voltage logic, and is designed specifically for that instrument!Fast forward 6 months and it seems two of the channels have now started playing up and do not respond to inputs. Neither can you see them responding during calibration, but ironically everything calibrates ok... We have been incredibly careful and ensured the module has only ever been removed or replaced without power! Maybe we haven't waited long enough after switching power off I don't know, that would be ridiculous!Has anyone else encountered any issues with this scope and the MSO module?Thanks.

author: hexreader
author_rank: Frequent Contributor
timestamp: July 15, 2018, 09:12:29 am
content: Well, I am a few months late replyingbut...I have had no problems with calibration, but I do find some logic analyser inputs to be intermittent.Current suspicion is that the connectors at each end of the ribbon cable mate poorly due to plastic covers prevent full insertion.Loosening the covers while fitted and allowing a little more plug to protrude seems to have cured the problem for now, but I suspect that I will end up sanding away some of the cover plastic to allow better mating.Will let you know if I have further troubles.If anyone wants to open the Logic Head, be aware that there are three torx screws holding the two halves together. They are hidden under labels, so your device will not look pretty once you have cut holes in the labels.Inside are 8 dual comparators with differential outputs (LMH7322), resistors and caps for signal conditioning and terminators and little else.EDIT: Starting to think that covers are only a problem at the probe end of the ribbon cable, which is the less troublesome end. Seems to be intermittent connection at the scope end, even with no cover fitted. Maybe I just have tarnished pins on the plugs??? Still investigating.... Still employing guesswork as main diagnostic tool

author: hexreader
author_rank: Frequent Contributor
timestamp: November 18, 2018, 11:40:59 am
content: Zip file with more pictures attached at PM request from modder_mike... as for connection problems, I have found that removing plastic covers from the ribbon cables solves all but one connection problem. The connector at one end still has a single pin issue, either where pin does not mate, or IDC connection is bad. Yet to determine which, as most of my test gear is in storage.

author: hexreader
author_rank: Frequent Contributor
timestamp: November 18, 2018, 12:01:09 pm
content: .... and also attached is spreadsheet of the connector pin functions. Don't take it too seriously, as a lot of guesswork was involved. The signal pins are probably correct though.Most of the pins around signal pins are ground, but I didn't bother to check fully

author: Howardlong
author_rank: Super Contributor
timestamp: July 08, 2020, 02:24:44 pm
content: Apologies for the necroposting.I have some information that may well be of use regarding certain individual channels intermittently failing.I've had the same thing, and earlier on in its life, it seemed to be corrected by cleaning the connectors with IPA and blowing some air into them to dislodge fluff etc.Much more recently, I've found that this action didn't have much effect.The nature of the fault is that over time various channels would come and go, almost as if there were some dry joints or one of those BGA ball problems. Some channels were more sticky than others.Adjusting the threshold level on the LA has no effect, but if you supply an appropriate square wave into the dodgy channels, such as from the internal signal generator if it's a DS1000Z-S model, you usually see a glitch pulse on the LA at transitions, but no square wave.Today I took mine apaaaaart, it'd come to the point where almost half of the channels had become unreliable.There's a very short 68 pin IDC cable assembly with an IDC header soldered onto the main board. I discovered if I applied light pressure to the top of the header, it had an effect on the LA channels.So I gently eased off the IDC ribbon header clip. After liberally applying IPA over the ribbon/blades, I individually firmly pushed each of the 68 ribbon wires onto each of the respective header blades with a 1.5mm flat bladed screwdriver I had to hand in an attempt to remake the cold weld.I replaced the top clip of the header, and this seems to have resolved it, for now at least: it's been on for an hour with no ill effects, typically I'd have seen three or four channels randomly come and go in that time. It may be that I'll need to revisit if this problem recurs, perhaps to make the header clip maintain more pressure to the ribbon cable.Edit: FWIW, over the years, I've pulled out and reinserted the RPL1116 cable while the scope's been on many times with no ill effects.Edit2: The LA Probe Cal also passes after the above intervention.

author: hexreader
author_rank: Frequent Contributor
timestamp: July 10, 2020, 03:51:58 pm
content: QuoteDo not apologise, this is a great bit of information.My scope LA has failed on more channels, to the point where it is unusable.I will investigate the internal ribbon connections to see if there is hope for improvement and post here if I have any success.Many thanks for the informationUpdate - There is a "Probe Cal" function? !!!!Saw it, but ignored it until now....... I think that this was all that I needed...Feel a bit silly nowBut many thanks - your necro-post seems to have solved all of my LA problems.

author: Howardlong
author_rank: Super Contributor
timestamp: July 11, 2020, 11:05:05 pm
content: Quote from: hexreader on July 10, 2020, 03:51:58 pmSo no need to open up? Lucky!To be fair I'd never noticed the LA Probe Cal option in the LA menu until I saw this thread either. When I ran it, I didn't find the brief instructions onscreen instructions useful, it wasn't clear to me if the LA cable needed disconnecting, or just the DUT. For the avoidance of doubt for others, yes, the LA cable does need to be plugged in for the cal to work, but not connected to any DUT. It won't cal successfully unless it's plugged in, which bearing in mind it's an active probe head makes sense.

author: TheCalligrapher
author_rank: Regular Contributor
timestamp: February 16, 2021, 09:03:04 pm
content: Quote from: Howardlong on July 08, 2020, 02:24:44 pmI just ran into exactly the same symptoms. I bought my MSO1104Z-S four years ago. I've never used the LA with it. The probe has been sealed in its original package all this time. Today I needed to use the LA. So, I unpacked the accessories, connected everything and... it failed calibration. Trying to use it resulted in registering very short spikes at rising edges instead of normal-width pulses in some channels. Here's an example: this is an 8-bit "running 1" patternThree channels with this problem in the D0-D7 range and three more in D8-D15 range.Loading the "Defaults" (per Rigol's web site suggestions) didn't help. Performing a master reset didn't help either. And the scope is out of warranty, the support told me.So, I opened the scope, removed the retainers from the connectors for the internal LA ribbon cable and gently squeezed with miniature pliers each little pair of those piercing "jaws"I've done this on both ends of this ribbon cable.Once I reassembled the scope, the LA probe successfully passed calibration. And all channels started to work perfectlyHopefully, this will prove to be a lasting fix.

author: jrmymllr
author_rank: Regular Contributor
timestamp: July 17, 2023, 03:58:33 pm
content: Had the same problem despite rarely using the logic analyzer. I tried getting the cover off the IDC connector and broke a tab despite being my usual careful self. I gently squeezed each pair of barbs and I still had failing inputs.So I decided to go all out and bought a new IDC connector ($13USD!!), new ribbon, and attempted to buy a new front panel connector but one that uses this fine pitch cable are impossible to find. In the end I got it all working, but getting that old connector off and clearing all the holes of solder, ugghhh.Perhaps having a hot air solder station would help, but after fighting with this for a few hours and finding my Pace desoldering wand didn't do the trick, I grabbed my $20 heat gun, set the air compressor to about 30PSI, put on goggles, and literally blew the solder out of the holes in the garage. Luckily this connector is far away from other important parts.

author: thunter0512
author_rank: Newbie
timestamp: April 02, 2024, 02:36:00 pm
content: Quote from: jrmymllr on July 17, 2023, 03:58:33 pmDespite being super careful I too managed to brake the tabs on both sides of the IDC connector soldered into the PCB.Nevertheless I managed to squeeze each of the piercing jaws. This fixed the problems with all 4 broken channels.I am thinking of using superglue to fit back the IDC cover.A better alternative would be to fit a new cable and connectors. Where did you get the fine pitch cable and the connectors on either end?My scope is now about 9 years old, so well and truly out of warranty, but is there some place which sells spare parts to repairers? I am in Perth in Western Australia

author: hexreader
author_rank: Frequent Contributor
timestamp: April 03, 2024, 11:23:26 am
content: @HowardlongYou are a genius!Many thanksI have spent so many hours chasing the wrong problems.Squeezing the IDC connections inside the scope seems to have (almost) solved all of the Logic Analyser problems.LA Probe calibration still fails, but the logic analyser seems to work perfectly for my purposes, despite calibration fail.Still a truly terrible logic analyser, but really handy to have more than four channels available on screen.

author: Howardlong
author_rank: Super Contributor
timestamp: April 03, 2024, 08:24:04 pm
content: Quote from: hexreader on April 03, 2024, 11:23:26 amYou’re welcome.QuoteThe LA in Rigol’s DHO900 series heads that leader board, by a very large margin.

author: jrmymllr
author_rank: Regular Contributor
timestamp: September 20, 2024, 01:30:03 pm
content: Quote from: thunter0512 on April 02, 2024, 02:36:00 pmSorry I rarely check this forum. I should more often.The ribbon I got from Digikey and the DK part number is MB68G-1-ND, and the PCB connector I had to get from Mouser, TE Connectivity 1-5111595-9. That fine pitch ribbon was hard to find and I couldn't get both from the same place. The front panel connector is impossible to find, but reusing the old seemed to be OK.