Rigol DG4062 Quality Control - Page 1
Forum section: electronics / testgear

author: feetwet
author_rank: Newbie
timestamp: July 05, 2014, 12:13:56 am
content: I just received my Rigol DG4062 a few days ago. I've been looking forward to getting a function generator for a while now. I chose this unit because both my oscilloscope and power supply are Rigol as well. As soon as the unit arrived I plugged the power cord into the wall, the other end into the unit and the house fuse blew right away. I unplugged everything and tried it again, the circuit breaker tripped once more. I never turned the unit on and the circuit breaker tripped the moment the power cord made contact with the back of the unit's plug. I suspected the power cord, so I got a different power cord from my oscilloscope and the unit powered right up. I then took my DMM and used the continuity tester to check the continuity between both ends of the cable. I found that the Ground on one end was connected to the Common on the other end. The question in my mind was how could Rigol not check this and how many others have seen this issue. I wrote Rigol about it and have not gotten a response back from them. In my opinion this can be pretty dangerous to cross-wire a power cord. I am beginning to questions Rigol quality control after seeming Dave's Youtube episode about the DP832 and now this problem that I am experiencing. I am wondering whether Rigol is still committed to making quality products? I will return the Signal generator I just don't know whether to replace it or buy a different brand. Any thoughts would be appreciated.Thanks,Feetwet

author: TooOldForThis
author_rank: Regular Contributor
timestamp: July 05, 2014, 02:37:24 am
content: The function generator will be 100% tested and calibrated in the manufacturing process. The power cord however, will be plucked out of a pile and tossed into the box just before they tape it shut. Power cords fall into the "not worth testing" category. The power cords, CDs, paper documents, and other minor accessories probably go through 'first article inspection' and then are never checked again unless they get complaints or they change suppliers.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: July 05, 2014, 09:01:45 am
content: Quote from: feetwet on July 05, 2014, 12:13:56 amProbably because (like most other T&M manufacturers out there) they just bought the power cords in from a 3rd party supplier, and the complexity of a power cord is low enough not to warrant re-testing of each production item by Rigol.I guess Rigol got a bad batch of cords. What they should do is to make a recall and replace the affected cords with new ones.QuoteWell, all manufacturer of complex electronic devices do occasionally have issues like this. Sometimes its defective power cords, sometimes external power supplies or batteries. Shit happens.However, if you don't have much confidence in Rigol (they really should have taken your complaint about the power cord more seriously) then send the thing back and get something else. Have a look at the Siglent SDG5000 Series. If I remember right a few members who had access to both seem to think that the Siglent is the better product anyways.

author: rf-loop
author_rank: Super Contributor
timestamp: July 05, 2014, 09:58:13 am
content: Quote from: feetwet on July 05, 2014, 12:13:56 amThis is very seious case. So serious that if this happend in EU area they need recall all equipments (or power cords) back and immediately give high alarm in some media. (We can see this many times in news papers when electric parts are danger and manufacturer/importer do call back. If there is this kind of power cord they need also try trace all sales and take contact to all end users who have propably purchased this level of danger equipment (power cord)I have tens of year experience with electronics but also with electric in factories and also in workshops.But also I hope know more and detailed information what was situation exactly and what was proofed findings. This is because if I understand right your explanation this is not enough for explain fuse blow.In power cord there is two equal wires where other is live and other is "neutral" or common or what ever it is named. And third wire, important for safety is GROUND or "Protective ground".This is only connected in equipment end to equipment base directly (and in oscilloscope case it is also directly same as scope GND.These other wires go to filter network inside scope PSU. Both these wires are isolated from GNG and so also from this power cord ground terminal.Lets give numbers for these three wires. 1, 2 and 3. Give 3 for this ground.1 and 2 for these equal wires where 1 or 2 may be livee and other is "neutral".In some countries this is polarized so that plug can connect only in one position to house electric network.If we change 1 or 2 with 3 inside this power cord. What happen?If 1 and 3 have changed and in house wall 1 is live (230V AC) where this current flow? Yes equipment GND have now direct live 230VAc but where is go if there is not any other connection from equipment GND to ground or "neutral". Do it blow house fuse? No it do not if house wiring is made normally (least this normal what is used in Finland)So I will more details what happend. (yes it is really good luck your house fuse blow and you know something is really wrong.Is it possible that inside rigol one AC input filter capacitor is short circuit or inside equipment happen other ways short circuit so that 1 or 2 have contact or too weak isolation distance (and leak) to equipment GND. Inside equipment these 1 and 2 are floating if all is ok and between 1 or 2 to 3 (GND) can be full 230VAc and nothing happend.So, where is exactly road for this current what blows house fuse in case that 1 or 2 wire in cord itself was swapped with wire 3. (normally this wire 3 is yellow/green)This is good to test and inspect deeply.If there is lot of these cases there is high risk for serius hazard and even death if user do not know this situation. It may happend so that people take probe to his hand and after then full 230VAC to hand and to his body and example via leg to ground. In this case it is easy to death because as long as current flow it is very difficult to open hand due to current.

author: feetwet
author_rank: Newbie
timestamp: July 10, 2014, 12:25:42 am
content: I wanted to update everyone regarding what I found out about the Rigol DG4062 unit that I purchased through Amazon. Even though the unit was purchased through Amazon "Prime" it was actually sent to Amazon from a company called Best Choice. Which as it turns out, to be a very bad choice (no pun intended). According to a technician I spoke with at Rigol they believe the unit was not supposed to be sold in the US market. They explained that the black power cord included with my unit was not how the unit is sold. They explained that their units are sold with a gray power cord with a higher gauge wire than the one I received. I did return the unit to Amazon, which will probably take sometime to get my money back and all the headaches associated with that process. The one good thing that did come out of this was that Rigol has agreed to locate a new unit for me at a discount for everything I have been through. I've never had a company offer to do that for me so will see what happens. In the mean time, I wanted to warn anyone trying to buy Rigol equipment through Amazon from non approved seller like Best Choice please beware. Also, I would like to say thanks to the technician at Rigol for all his help.

author: Nerull
author_rank: Frequent Contributor
timestamp: July 10, 2014, 01:06:50 am
content: I've worked for a company that makes FDA Class 3 lifesaving medical equipment. They pluck power cords out of a big box right and toss them in when packing them for shipping.Rigol power cordsaregrey, though.