RIGOL DP811 REPAIR - Page 1
Forum section: electronics / repair

author: cidak
author_rank: Unknown
timestamp: January 03, 2024, 03:49:08 pm
content: Hi everyone.Big thanks in advance to the people who can help solve my repair problem on RIGOL DP811 (SINGLE OUTPUT 20v/10a 40v/5a).I stupidly turned off the power supplywhile a charging battery was connected to the output.This incorrect operation caused an SMD current detector shunt resistor to burn out.I can no longer read the valuebecause it has burned out...Can anyone check its value on their power supply, or indicate and/or provide me with the electronic diagram with part list of components of the DP811.The position on the printout is R52.I found some photos of a teradown of DP832, (the value is 0.020 Ohm) But the value used by Rigol on DP811 is different.I can't read the value because the current detector resistor has burnt out. Who can kindly help?Spending $1000 on a new power supplyfor a stupid $2 resistor is crazy.Help!!!Thank you

author: fqahmad66
author_rank: Regular Contributor
timestamp: January 08, 2024, 10:24:56 am
content: This should not happen....any pictures please??

author: MegaVolt
author_rank: Frequent Contributor
timestamp: February 07, 2024, 09:57:00 am
content: Quote from: cidak on January 03, 2024, 03:49:08 pmI have this power supply. And I can teardown it through a month.If you are willing to wait a month, let me know.

author: TurboTom
author_rank: Super Contributor
timestamp: February 08, 2024, 02:29:50 am
content: My DP811 (lower board) identifies the shunt as R15. Unfortunately, apparently there's no marking on the resistor -- at least in the photo that I took of the PCB some time ago, there isn't anything recognizable that looks like a marking.The DP811 is a very peculiar PSU with an SCR across the output that (sometimes) seems to act as a crowbar. I experimented with a paralleled, second lab PSU (low current setting) and found the 811 to enter a shorted output condition when I turned off its output while the other PSU was still supplying some voltage. IIRC, this happens only in a certain voltage range, and if I enable he 811's output while it's still in this "latched-up" state, it shorts out itself! Obviously, as long as the currents involved are low enough, nothing serious happens. Of course, a battery hasn't got a current limit, so the magic smoke will get released.That's why Rigol recommends to always use a decoupling diode in series when charging batteries with their PSUs.If time permits, I may open the PSU again and take a measurement of the shunt. But please let me know if the PCB in your 811 is identical with mine, otherwise Rigol may also have used a different value shunt and the whole "business" may be futile...

author: _Wim_
author_rank: Super Contributor
timestamp: February 09, 2024, 06:42:52 am
content: I would just install a current shunt (for example 0.02 ohm or whatever you have available), use the power supply in constant current mode for example outputting 1A, and measure the actual current with your multimeter. If the current is twice as high as it should be, you know your current shunt must be two times bigger, similar if too low. This way you can calculate what the actual shunt value needs to be.

author: PaulR282
author_rank: Newbie
timestamp: August 20, 2024, 04:00:53 pm
content: Hi,If you still need the value: it's R008 (8 mΩ).

author: cidak
author_rank: Unknown
timestamp: January 16, 2025, 04:54:51 pm
content: A thousand thanks!!May God reward you!HI.