My Scope came with one of the
really noisy fans. Within 0.5M, I couldn't stand the noise/whine. I decided to find a quiet & hopefully cooler solution.
I know a couple others did mods with 80, 92 and 100mm fans, but I wanted to take the time to illustrate the benefits/tradoffs so people could determine if/how they wanted to take on the challenge. All the pix I remember seeing were 25mm deep, and weren't favored because the fan hits the bench.
First, I attached the stock fan cable to 15mm thick Thermalright fans.(Amazon $6.29USD each)
Fan 1: 80x80x15mm, <23.3 dBA 28.40 CFM 0.07A @12Vdc
Fan 2: 92x92x15mm, <22.4 dBA 42.58 CFM 0.18A @12Vdc
Note: stock fan is spec'd at 0.17A @12Vdc
FYI: All these tests are running on the internal @8Vdc provided by the original fan connector
I removed the stock fan from the heatsink, to decrease the turbulence and allow more laminar flow. I observed >1C drop after removing the fan, so I left it off for the rest.
I started with the 80mm. The hardware included with the Thermalright fan fits in the DHO hexagon grid hole pattern nicely.
I located the fan so it misses the RIGOL logo. Less turbulent air noise this way.
Next, using the 92mm fan, I had a bit more difficulty aligning the holes, but managed a location with maximum air flow, but not quite perfect bolt arrangement. i.e., It works, but not as good looking 'cuz I had to turn a couple backwards from the others. (Mechanial crash)
My factory stock fan, starting temps were always very close to 60C(~59.x), but I only found one saved screenshot at 58.3/55.5 @ 25-26C ambient.
After the mod, all channels active, +math, minimum of 1 hour cookin' at 26C ambient:
80mm =
55.5/52.7C 80mm =
53.8/50.5C (As a test, I blocked the remaining hex holes around the fan with tape to force all incoming air across heatsink)
92mm =
48.7/46.2C I didn't tape up the surrounding holes, but I can if someone needs to know what the delta is.
I didn't order a grill for either fan, but definitely found out what happens when you stick a finger in the blades.
It very politely waits for a few seconds, then restarts. I don't know if that's the fan or the 8V switcher recovering from the stall condition.
Some things to note:
1. Oh yeah. It's Silent now... At 1/2 meter, you can't hear a thing. Tiny amount of air noise on the backside, directly at the 92mm fan, even less on the 80mm. (like, not even worth trying to measure)
2. It's a well known fact that cooler=better with IC's., but now you can decide if the upgrade is worth it to you.
3. If you don't want to clip/solder your stock fan cable, you could get a JST/Molex or other female connector with 2.54mm/0.10" spacing.
4. I may try to enhance the heatsink surface area by
adding a small heatsink to the area where the stock fan
was. I definitely think it would be worthwhile to do. I have a 40mm
2 sink, but it was a bit too big for that spot, un-modified.
5. If you can find a 80mm at 35 CFM with a reasonable dBA, it might be just about perfect to run at 8V, or maybe run this one at 12V?.
6. Thread locker might be important when the nuts are on the inside. Or use plastic?
Hope this helps someone "upgrade" their 'scope to a quiet, cool running one...
Edit: Update -- Be sure to check out the excellent
120mm fan upgrade by @shapirus that I completely ignored when I did my mods. --Sorry again for that!