MikroTik

RB750G board missing component parts.

could anyone help me *please* to identify component missing parts, (name, type).
so i could find component replacement on the market.
(smd?) component code listed on the board as c811 and unlabeled one.

please take a look at the link :

1. zoomed, selected board area picture:
link : https://imgur.com/a/yeGlTDw


2.full board picture:

link : https://imgur.com/a/8pNqSjJ

thank you for any help.
(im not native english no good. )

that is just a ceramic "filter" capacitor. it's value is, for the most part, non-critical

measure the voltage across the rail, get the largest one that fits the space (from the looks, somewhere from 0.47 to 2uF )

that missing cap should not keep the board from booting tough. if it doesn't beep, there is likely some other defect.

that is just a ceramic "filter" capacitor. it's value is, for the most part, non-critical

If it were a single cap, then what you say might be true within a range of about 10x, but there are many applications where going beyond that will give bad performance. A perfectly working circuit can utterly fail to start if the capacitive load on it is out of its design range.

But when there are three in parallel, as here, then the value is more important because it means what they're doing is overlapping impedance curves to get a better overall behavior than you can get from any single off-the shelf cap. Matching one of the other two values doesn't achieve that end. You need a third value that's sufficiently far out from the other two to get the desired performance.

That said, what I really want to know is why that cap is missing. The board looks dirty. If something shorted and caused that cap to be turned into a fuse, it's gone for a reason, and its replacement will likely disappear soon after power-on for the same reason.

get the largest one that fits the space (from the looks, somewhere from 0.47 to 2uF )

You can only make that judgement if you know the voltage rating and dielectric type in use. A C0G 25V cap with a given value will be far bigger than a 6.3V X7R cap of the same value.

Someone with actual knowledge of the circuit should say what is supposed to be there. Don't guess.

thanks for reponses,
im able to replace 6.3v 560uf capacitor, just replace the leaked one with solid cap.
smd cap still unidentified. i will find another used rb 750g.