Fast, simple and cheap fix of a design flaw
Tutorial for a reversible modification of the Nanlite Forza 60 projectors to reduce the noise generated by the cooling system
As always, a full list of the articles in this blog can be found HERE.
Introducting the problem
For my work, I use several lights from Nanlite’s Forza range, including the Forza 60s which are 60W COBs in mono-color at 5600K. With the 300W models, the Forza 60 are among the first lights in this format developed by Nanlite and these have some youthful flaws. Most of them have been corrected in the versions II of these lights which have been released recently. For example, they have a glass protector on the COB, a reinforced locking system, but above all an improved ventilation system. Multiple fan speed settings are now available, and overall noise levels are greatly reduced.
It is this last point that bothers me the most on the Forza 60s, which are quite loud for the light they give. They still have a completely silent mode which cuts the fan off but limits the power output to 30W (loss of about one stop of light), so this is not a real solution.
While researching, I saw that some people replaced the noisy fan of the Nanlite FS300 (the entry level version of Forza 300) with a quieter one. I took a Forza 60 apart to measure the dimensions and note the specs of the fan, but it turns out to be way too complicated to unplug the fan. The connector is glued while the cable is slid behind the PCBs. No luck there.
I built quite a few PC towers and had noticed excessive noise when the fan was stuck too close to a grille, such as on the honeycomb pattern on the exhaust of some cases. One solution was to add a greater distance between the fan and the mesh to reduce interference.
To access the Forza 60 fan, I had to remove the protective grille. I noticed that the fan here was also very close to it and therefore wondered if it was not creating turbulence. I turned on the light without putting it back on and the noise was indeed reduced.
I also have a Forza 150b, a much newer design. I saw that in addition to a less noisy fan, it is recessed several millimeters away from the grille and that might also help noise performance.
The problem now is that the fan and electrical contacts are exposed, which makes handling the light a hazard. To fix it, I ordered round fan grilles on the net for a few euros. The fan being standard and in 60mm format, the choice was wide. I also cut a small cover in a thick plastic plate to protect the rear contacts and PCBs.
Fan noise comparison
I did a quick test between an unmodified Nanlite Forza 60, one from which only the grille was removed, and a final one modified as described above. I placed the projector on a stand in the center of a room at a height of about 1m, with no obstructions around it. I placed a Sony FX30 equipped with an AT8024 camera microphone set to Mono at the same height, the microphone pointed at the back of the projector at a distance of 50cms. The camera recording level was +31 (the maximum). I edited the clips in DaVinci Resolve, adding only +10db to each track.
Modding the light
Foreword and necessary materials
No parts are modified and the assembly is fully reversible. Just keep the original grille in the lighting bag to always have it available. The integrity of the projector and the cooling system are not affected, so there is no risk of overheating.
Keep in mind that warranty might be voided and to do this modification at your own risk.
You will need :
– A philips head screwdriver
– A 3mm allen key
– A 60mm fan grille
– A solid piece of plastic
Tutorial
It is better to keep the plastic protector on the COB to avoid damaging it.
The fan grille is not fixed and can be taken out by sliding it out of the grooves of the housing.
Once the grille has been removed, the front housing can be screwed back on as all the other screws are accessible even after screwing it back in.
Next, I unscrewed two of the four screws holding the fan to the aluminum cooler. It is possible to remove the four to install the new grille but I noticed that it produces less noise screwed in this way than fixed by four screws.
Screwed on only two corners, the grid is still solid and being slightly offset, the turbulence noise generated is minimal.
All that remains is to hide the PCBs and prevent any intrusion. To do this, I cut a cover from a solid plastic plate that fits into the grooves housing the original grille. I added a bit of electrical tape for safety to hold it in place.
