Rigol DS1104B, problems - Page 1
Forum section: electronics / testgear

author: SaleB
author_rank: Contributor
timestamp: July 14, 2013, 03:56:14 am
content: Hello all,I have recently acquired an used Rigol DS1104B. This is my first post in the forum, but I have been following the youtube channel from time to time. I see here are many discussions about 1052 model, so I hope that you could be able to help me with my scope too. I am not proficient in electronics, and this is the first DSO that I use, but I had experience with analog scopes and digital automotive scopes. I wanted some nice piece of equipment for small home electronic lab that I am piecing together. I have bought it in another country, when doing that I tried the compensation signal on all four channels, played a little with the controls and bought the unit that is looks very nice without traces of use.Now, when I transported it home I have been playing with the settings for a few days and came to a conclusion that the unit may have problems with trigger. I have a live signal on display, but when I apply the internal trigger on the same channel, the unit goes to a waiting loop. I have not yet tried using trigger from second channel, because I have only one probe, but I could semi-stabilize the signal by use of AC line trigger option. In that case, I have only one live trace on the screen (one for each of the first two slope options, and two traces for the third option) that moves slowly to left. I do not have a function generator yet, so I cannot try other input signals.The other problem that I have, I cannot explain in detail, but the amplitude is not real for all scale settings. For example, I have read in instruction manual that the calibration signal is approx 3.2Vpp, f=1khz. I am getting 3.2v when scale setting is 2v/div, but when I go to 1v/div and then 0.5v/div I am getting smaller and smaller signal (less vertical divs for the same signal) and then, going down from 100mV/div I get again realistic representation, but much smaller. What I wanted to say is, on 100mV/div I have one div Vpp signal, on 50mV/div I get two divs, but I cannot read 3.2v in any other setting then 2v/div. On the other hand when I move to 5v/div, a relay clicks and I get only some noise with Vpp approx 0.5v (I cannot really see if it's square wave without trigger). When I click on Auto setting, the unit selects 100mV/div.I have not yet tried ethernet connection, usb for storage or to pc, I kind of, stuck on trigger and did not go further. In single and manual trigger modes, when triggered internally the display stays blank, and upper left corner says WAIT. The probe I used is a Fluke PM 9010/001, a 10x probe paired with 10x setting for corresponding channel. I have tried a factory reset, but could not get anything with it either. When booting up I found out the software version is 00.04.00 SP01.I hope that it's not a hardware problem.Thankful in advance,Sasa

author: saturation
author_rank: Super Contributor
timestamp: July 14, 2013, 12:14:41 pm
content: Did you reset the scope to factory, then do an auto calibration? If not try it as it does sound like cal is off.

author: SaleB
author_rank: Contributor
timestamp: July 14, 2013, 01:39:03 pm
content: Yes, I have done both of those. Factory reset and automatic calibration of the unit. No improvements. Any more ideas?

author: saturation
author_rank: Super Contributor
timestamp: July 14, 2013, 05:02:00 pm
content: Sorry to read, what you did was the easiest and quickest option. My gut tells me someone overloaded the input and there could be hardware issues.Without a function generator, test the vertical amp calibration in DC and compare it against your DMM. You can use a DC power supply or just batteries.If the vertical settings are still off in DC there is clearly something wrong. You could try reflashing the firmware thereafter as a last resort to sending it to factory.

author: SaleB
author_rank: Contributor
timestamp: July 15, 2013, 03:57:11 am
content: That would be really sad news, but I think you may be right. The measurement left me puzzled. Measured battery is 8.5v measured with DMM. Measuring results with scope on CH4:Range Vmin Vmax Vpp50mV -10mV -8mV 2mV100mV -8mV -4mV 4mV200mV -40mV -32mV 8mV500mV -60mV -40mV 20mV1V -0.24V -0.16V 0.08V2V -0.48V -0.4V 0.08V5V -0.4V -0.4V 010V -0.8V 0 0.8V20V -4V -3.2V 0.8V50V -6V -12V 4V100V -16V -8V 8VOn the other channels I had different but also wrong results, and I double checked signal inversion is set to off and coupling DC coupled.On the other hand, I played with some simple NE555 circuit and could see trustworthy duty factor changes while moving a pot, but vertical was gibberish also, Vpp changed trough various ranges. On the other hand I could pick a trigger and stabilize signal while measuring NE555 output.

author: saturation
author_rank: Super Contributor
timestamp: July 15, 2013, 04:20:07 pm
content: Yes, it does look like the input stage has been damaged. I'm not sure how different the input stage is from the 1052e, but A Hellene painstakingly made a schematic of the front end here:http://rigol.codenaschen.de/images/0/0c/DS1052E_HW58_PCB_Schematics_-_Ch1_analog_front-end.jpgIf you aren't going to send it to Rigol for repair it maybe only be the voltage divider resistors or capacitors that are faulty and easy to repair, worst case.Have you tested each of the other 3 channels? Its unlikely all 4 are damaged.

author: SaleB
author_rank: Contributor
timestamp: July 24, 2013, 10:55:13 pm
content: Sorry I took some time, had not much time to play in the mean time. I have the same on the other channels, but the ch4 and ch2 are the only ones that give signals from my ne555 circuit, the other two do not do even that.In the meantime have I also received the answer from Rigol EU. They also think that there is a hardware failure and do not recommend firmware change before hardware service. The unit is, they say, about 2.5yrs old and has not it's original firmware in it, because the firmware is newer.Thank you for all your help,Sasa