Rigol DS1054 Accuracy problem (Volts reading) - Page 1
Forum section: electronics / testgear

author: fivefish
author_rank: Frequent Contributor
timestamp: July 27, 2015, 05:07:18 am
content: I bought a Rigol from TEquipment last June, so this scope is just 2 months old and not used daily.Tonight I noticed Channel1 voltage readings are way off in accuracy.10Volts DC input is being displayed as 8.8Volts. All the other channels report 10.2, 10.4, and 10.0.I tried Utility -> Self Calibration but it didn't help.I contacted Teq to see what they'll do, but wonder if anybody else have noticed this problem, or I just got a bad unit?

author: tautech
author_rank: Super Contributor
timestamp: July 27, 2015, 05:52:51 am
content: Post a Screen shot capture please.

author: alsetalokin4017
author_rank: Super Contributor
timestamp: July 28, 2015, 01:09:27 am
content: Did you try swapping probes around, to see if the probe itself might be the problem?(Just guessing. Screenshot, yes please...)

author: fivefish
author_rank: Frequent Contributor
timestamp: July 29, 2015, 09:33:12 pm
content: Rigol just contacted me back and asked for screenshots. Don't know yet if they're going to repair or replace my 2-month old unit.After calibration, measurement at probe compensation point (Rigol asked me to do this).10VDC at Channel 1. Error/difference just gets worst and worst at higher voltage readings.

author: SaabFAN
author_rank: Frequent Contributor
timestamp: July 29, 2015, 10:43:38 pm
content: Reference-Voltage inside the unit damaged?Or some crazy attenuator-setting == Firmware-Problem? Have you tried updating/refreshing the firmware?

author: fivefish
author_rank: Frequent Contributor
timestamp: July 29, 2015, 11:14:48 pm
content: At 10Volts input, the error is 1.2Volts difference.At 20Volts input, the error is 2.5Volts difference.At 30Volts input, the error is 3.6Volts difference.I'm seeing a pattern here... approx 1.2V error per 10V input.

author: vk6zgo
author_rank: Super Contributor
timestamp: July 30, 2015, 07:03:52 am
content: I was going to ask if it was just the readout which was wrong,but looking at your screenshots,it appears it is both the displayed voltage and the readout which have the problem.This is an important point as far as troubleshooting is concerned,as it can save the Rigol guys time in finding the possible problem.AAAAGGGHHH!,I hate trying to make sense of DSO screenshots with all that other extraneous grot on screen!

author: fivefish
author_rank: Frequent Contributor
timestamp: July 30, 2015, 03:46:29 pm
content: FAAAAKCCCKKK!!It's been a very frustrating morning dealing with Rigol all morning. Making me jump through hoops, do this, do that, telling me maybe it's a firmware problem, update my firmware, etc etc... , instead of just issuing the damn RMA and sending a replacement for a 2-month old, barely used unit. Now it looks like they just wanna repair this brand new unit instead of issuing a replacement.

author: pascal_sweden
author_rank: Super Contributor
timestamp: July 30, 2015, 03:56:41 pm
content: If someone on this forum has a blank RMA form, maybe it should be shared to the community.Then you can just send the scope together with the RMA form, and play safe from the start, to guarantee that you can get a replacement scope up front.Pro-actively influence the process to come to the right outcome

author: ebastler
author_rank: Super Contributor
timestamp: July 30, 2015, 04:27:25 pm
content: Quote from: pascal_sweden on July 30, 2015, 03:56:41 pmNot a good idea, I think. The RMA process is not about obtaining a form, but about obtaining the authorization to return the (particular) unit for which the RMA is issued. Don't know about Rigol, but most manufacturers I have dealt with will also issue an individual RMA number, which is linked to the case and customer in their database.

author: fivefish
author_rank: Frequent Contributor
timestamp: July 30, 2015, 05:00:14 pm
content: Updated firmware to latest per their instructions.... now the scope "fails self-calibration, please try again" message.The saga continues....

author: pascal_sweden
author_rank: Super Contributor
timestamp: July 30, 2015, 05:53:32 pm
content: How would the Rigol department judge whether it is economically viable to repair the scope, or whether it is cheaper to just replace with a new scope?Is the repair done at the European HQ in Germany?If the actual troubleshooting and repair in Europe takes several hours or even more than one day in total, it seems cheaper to replace it.I really wonder how they judge on this? Most likely they have some failure categories, and somewhere a threshold point between repair or replace, based on the actual failure category. But probably it also involves some good will based on the person that is handling the RMA case?Is their a committed max. turn-around time period for an actual repair? Or is it really possible that an end user has to wait more than a month for his repaired scope? What does the end user have to do in the mean time? Pull out a vintage analog scope or a low-cost Vichy multimeter?

author: fivefish
author_rank: Frequent Contributor
timestamp: July 30, 2015, 06:19:43 pm
content: I got my RMA, and also sent me a free Fedex label going to them.And they said there's a repair board in stock so estimate 10 days turnaround time. I don't know if that includes transit time to-and-from.In the meantime, I'll be back using my just repaired Tek 2445A... which this Rigol scope helped me fix.

author: Bud
author_rank: Super Contributor
timestamp: July 30, 2015, 06:21:59 pm
content: Quote from: pascal_sweden on July 30, 2015, 05:53:32 pmPerhaps spend some time thinking if to buy rigol products ever again?

author: fivefish
author_rank: Frequent Contributor
timestamp: July 30, 2015, 07:00:33 pm
content: I expected Rigol to not last as long as my Tek 2445A, but didn't expect it will need repair within 2-months. The scope still "works".... just gives the wrong answers for Channel 1.All in all, still a great deal at $100/ch... just buyer beware of QA and long term reliability.On another note, my 2445A also developed a similar problem with it's Channel 1 (wrong readings) and I traced that problem to it's attenuator, one or more internal relays not working properly... but hey, it's a 1987 era equipment so that's to be expected, mechanical parts starting to fail.And a few days ago, I was thinking of getting a Rigol signal generator to replace my Instek one.Instead, I just got today an HP 8904A, which is more suited for the audio work I'm doing. I don't need Megahertz range, but the 8904A's balanced out and floating ground capability and other features will be more useful to me.

author: pascal_sweden
author_rank: Super Contributor
timestamp: July 30, 2015, 07:04:35 pm
content: Quote from: Bud on July 30, 2015, 06:21:59 pmI was looking for a "Like" button on this forumBut given that Rigol has such long turn-around times in the repair flow, one would expect that they are really repairing your own unit, and that you will get the original unit back. At least that clarifies why the turn-around time can be high. Otherwise I can not see why it should take that long time to just pull a refurbished unit from the refurbishment pool

author: tautech
author_rank: Super Contributor
timestamp: July 30, 2015, 10:20:58 pm
content: Quote from: fivefish on July 30, 2015, 03:46:29 pmWho is this "Rigol" you are dealing with?Why wouldn't you just deal with yoursupplierand have them "jump through hoops"?They know the internal processes far better than you and likely have direct contact with Tech support.Surely you're making the process harder than it needs to be.But by all means document the problems you're having.

author: fivefish
author_rank: Frequent Contributor
timestamp: July 30, 2015, 10:29:07 pm
content: TEquipment won't replace the unit because it's over 30 days old.Instead Tequipment gave me Rigol USA contact details.The Rigol USA tech guy feels sorry for me since the unit was just over 30 days old, not even 2-month old... so he just sent me a free Fedex label to ship it to their Oregon facility. He estimates 10-day turnaround time, he contacted their repair center and there is a spare repair board for my unit, and they'll be waiting for it.So yeah.... that's the extent of the tech support I got from Tequipment. Them giving me a phone# of Rigol USA to contact myself. ... on a barely 2-month old scope.

author: pascal_sweden
author_rank: Super Contributor
timestamp: July 30, 2015, 10:33:03 pm
content: Yes, normally if the scope is within warranty, you just have to send it to the supplier, and they will follow the appropriate procedures. You bought the scope from them, and they still have responsibility for the scope under the warranty period. Same as the relationship with a car dealer and the company producing the car

author: fivefish
author_rank: Frequent Contributor
timestamp: July 30, 2015, 10:35:37 pm
content: Of course it's still in freaking warranty. But this is my supplier (Tequipment) response.Quote

author: pascal_sweden
author_rank: Super Contributor
timestamp: July 30, 2015, 10:41:03 pm
content: Maybe you should send TEquipment the following Wiki linkhttps://en.wikipedia.org/wiki/Loyalty_business_model

author: dadler
author_rank: Unknown
timestamp: July 31, 2015, 08:08:30 am
content: Quote from: fivefish on July 30, 2015, 10:35:37 pmSounds like a perfectly acceptable response. Their return policy is well defined. I just had to send my 3 month old DS2000 back to Rigol in Oregon at my own expense. Purchased from Tequipment.I can't understand why you are upset.

author: pascal_sweden
author_rank: Super Contributor
timestamp: July 31, 2015, 07:10:46 pm
content: It's all about customer service.The supplier could collect a badge of scopes coming from different users, that need to be returned to Rigol, and could send them in together with a discounted shipping rate, given that they would have a corporate contract with DHL or UPS.The supplier would obviously get better attention and service from Rigol, in contrast to an end user.Rigol has to live up to the expectations of their supplier, but not to its end users.At least it would get more attention from Rigol, as they know that the supplier is in the loop.It all depends on good will from the supplier. I am sure many suppliers do it exactly the way I describe. I was expecting the same from TEquipment, given their size.

author: Zero999
author_rank: Super Contributor
timestamp: July 31, 2015, 07:38:35 pm
content: Quote from: dadler on July 31, 2015, 08:08:30 amWow that's shit and would actually have a violation of consumer law in the UK. The supplier should pay for return shipping if it's a defective product: your contract is with whoever you bought it off (not the manufacturer) and the supplier should deal with all returns.Things may be different in the US though.

author: dadler
author_rank: Unknown
timestamp: July 31, 2015, 07:41:50 pm
content: In the USA we don't have things like meaningful consumer protection...but we do have a lot of guns and churches!

author: fivefish
author_rank: Frequent Contributor
timestamp: July 31, 2015, 08:15:04 pm
content: QuoteI hope that's sarcasmIf I spent $1100+ (depending on your DS2000 scope model) and after 3 months it has to be sent back for repair, yeah I would be upset.I'm surprised you're not. You must be a better saint than me.I'm disappointed because if you add up all the HOURS that scope was actually powered on, it will probably just a few days of ON time.The rest of the time, it was just sitting on the bench, powered OFF --- Meanwhile, the 30 day clock is ticking.Basically, Rigol is the shit when it comes to quality. Problems come up after just few hours/few days of actual ON time.

author: dadler
author_rank: Unknown
timestamp: July 31, 2015, 08:57:52 pm
content: My faith in Rigol products has dropped quite a bit, and so I am indeed reconsidering any future Rigol purchases. However, this sort of stuff happens. Products are defective. These are entry level, tiny-profit-margin products, the low price comes from somewhere.Life is too short to get emotionally upset over stuff like this. It is frustrating, the scope I paid for (which had only been on enough to use up half of the trial hours) is not doing me any good, it's on a FedEx truck.However, I knew the Tequipment return policy going into this, so I am not upset. They did their part. When my DSA815-TG came from Tequipment and I discovered the display was defective, they exchanged it and paid return shipping. They did hold onto it for a week before shipping out a replacement, which I was not happy with, but when I complained they expedited the shipping.Anyways, I digress... I'm just saying that Tequipment did their part and are following their stated policies. The way Tequipment can offer low prices, free shipping, and the EEVBlog discount is by maintaining policies like this. Extended return policies can be expensive when your profit margins are thin. If you wanted the option for an extended return policy, perhaps you could have found a vendor that would do so. But I would expect the price to be higher.If anything, you should be upset with Rigol. It's their QA etc that failed you here.Anyways, just my personal opinion.

author: alsetalokin4017
author_rank: Super Contributor
timestamp: July 31, 2015, 11:10:13 pm
content: Burn in your new digital equipment! If it is going to fail from component ageing, heat buildup, or other quality issues, it is far better for it to do so while still in the _vendor's_ return-replacement interval!Open the box, check for all the stuff you're supposed to get, then plug it in and turn it on, set it to some task like watching its calibrator output, and _leave it on_ in the operating environment! Run it for days! Cycle the power often! If it's gonna fail, you want to know about it while you can still return it to the vendor for replacement from their stock!

author: vk6zgo
author_rank: Super Contributor
timestamp: August 01, 2015, 05:15:11 am
content: Quote from: dadler on July 31, 2015, 07:41:50 pmIf your gun fails in the woods,you won't be around to access consumer protection,anyway,because the bear will eat you.The upside is that the church will ensure you have a nice funeral!