Products > Test Equipment
DP832 - Fan Replacement 2018
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Gandalf_Sr:
Go back and read my first post.  There's a picture of the PCB with a large resistor that I drew a red rectangle around in one of the pictures.  That resistor carries the current drawn by the fan and the voltage across that resistor is what the DP832 uses to detect whether the fan is running or not.  You need about 1.2V across it when the fan is running, achieve that and the DP832 will not have issues with failed fan messages.  Its really simple, Ohms law.
Gandalf_Sr:
I got a second DP832 a week ago and ordered a new fan, same one as before. I took the lid off today and the PCB is a new one and there is no big resistor!  I took pictures and will add soon but what did I do?

I measured the current draw of the old fan at 120 mA, the new one is only 60 mA so I added a 200 \$\Omega\$ 2W resistor (4 x 820 \$\Omega\$ 1/4 W resistors in parallel) and put that across the fan connection.  My calculations say that it only draws 0.7W so 2W seems reasnable.

It runs fine. I loaded up the supply and the fan cranked up to cope.
mbedwani:
Looks like Rigol has changed the Fan to new model (Protechnic) in by new PSU. I used a Noctua NF-A8 FLX 3 pin FAN, Here is what I did.

https://bedwani.com/wordpress/2021/07/07/making-the-rigol-dp832-psu-quiet/

Mark.
pushrax:
I have an older DP832, and finally got around to doing this mod. Thank you to everyone who posted useful information here. First I removed the grill with a dremel, and then replaced the fan.

My unit's board had a 7.5 ohm current sense resistor like the original poster. I measured around 1.2V across the resistor during boot up when fan spins up to max (~160mA draw). My replacement fan (some old DeepCool fan I had laying around) measured around 0.7V during that step (~90mA draw).

1.2V/0.7V ≈ 13Ω/7.5Ω. I desoldered the resistor and replaced it with 13.5Ω (two 27Ω 0.25W resistors in parallel). The unit is working perfectly and is super quiet now.

The total power across the current sense resistor peaks ~100mW, so minimal waste.
sequoia:
I also ended up replacing the stock fan, as it was unbearably loud...

Used also Noctua NF-R8 redux-1800 (non-PWM version).

My unit has V03.02 top and bottom PCBs (dated 2018-06-12) and the fan current sense resistor is now done using three SMD resistors (although looks like through-hole resistor could still be used with this PCB, see attached photo...R210 vs R206-R208)
 
Didn't feel like taking everything apart to be able to swap out the current sense resistors, so made a short adapter cable from 2-pin JST to 4-pin PC fan connector (female), so no need to modify fan at all.... 

I ended up also using a parallel resistor in the adapter cable to avoid fan error... 330ohm 2W resistor brought up the current current consumption within 5mA or so to the original stock fan (my unit came with a Protechnic MGA8012HR-O25 fan).

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