I recently decided to modify the motherboard of my NAS slightly because I found the LEDs to be way too bright, especially at night.
Before reading the following, please know that I can in no way be held responsible for any damage that your equipment may suffer during or / and after this type of intervention.
To carry out this operation, it is necessary to completely dismantle the device, and it goes without saying that it is necessary to have all the adequate tools, whether it is the hand tools ( Pozidriv PZ1 screwdriver ) or the iron. welding. I personally use a station for this procedure+ a ironwith a very fine tip ( Ø 0.4 mm ).
The dismantling is not complicated, I did not take pictures during this phase. Disassemble and remove all mechanical parts until you reach the motherboard. This is absolutely necessary because the part of the circuit to be modified is located under this chassis and is therefore not directly accessible.
This being separated from its frame, it becomes possible to carry out the desired modification work.
To scrape off the protective varnish from the circuit board, I use a . The advantage is that it does not damage the copper tracks and that the tinning then becomes very easy.
The operation consists of reducing the current flowing through the LEDs, and as they all have their anode connected to the positive pole of the regulated power supply ( + 3.3V ), it suffices to cut this connection and insert a resistor in it. CMS 0603 [1608 Metric] of 470 Ω, see photos displayed below. I determined this ohmic value by a few successive tests, in order to obtain the level of luminosity that I was looking for.
Nothing prevents you from decreasing this value ( for example 330 or even 270 Ω ), it all depends on what you want to obtain as a result.
It is not possible to replace these LEDs with conventional low light models as they are also in SMD package, so series resistor is the best option.
The current measured through this resistor following this intervention was 2.69 mA.
Finish by cleaning the solder flux residue using, for example, a simple cotton swab soaked in methylated spirits.
All that remains is to reassemble the device, obviously taking all the necessary precautions.
Note : The CMS 0603 [1608 Metric] or possibly 0805 [2012 Metric] box is essential because the space between the printed circuit and the chassis is small. In my case the component comes from a recovery card ( I have several in a drawer ... ).
Do not perform this operation s i :
- your device is under warranty, in which case you would lose it ...
- you are not sufficiently equipped for this ...
I did this work on the Synology DS212J NAS that I own, the maintenance of electronic circuits was my job.