Need values for some Capacitors on a Slim Controller Board (1708)

[jasaleja]

Hi, I found this thread which is really helpful. https://www.acidmods.com/forum/index.php/topic,43981.0.html

I have a problem, my controller is not working and turning on but is heating and i found that the C23 is shorted and is the source of the heating.

Does anyone have the values for C20 and C23 and is there a source where I can find all the values?

Do you have any tips for me for the repair that is ahead of me?

Thanks in advanced.

[RDC]

C20 and C23 are both 10uF ceramic SMT Caps, 0805 size. Voltage rating for the replacements should be 6.3v or more. You could put anything from 10uF to 100uF in there and it'll be fine for a replacement.

If you want to know every capacitors value, you'll need a cap checker, a 100% working controller to remove cap by cap and a pile of time to absolutely waste documenting it all, and then it would mostly only apply to that version of controller.

They are just for decoupling (DC filter caps) so remove them both and power up the controller to make sure everything still works fine, and if it does then replace them. If it still acts up, it could be U3 is bad, L4 is damaged or pretty much anything on the controller, as that U3 regulator is the 3.3v source for pretty much everything on there.

[jasaleja]

I am very thankful for your kind and VERY helpful answer. I will follow your tips, and report if everything worked fine.

[jasaleja]

I removed C23 because it was shorted and heating very much. U3 and C20 are also heating. I checked C20 and as far as I can tell, it is not shorted, which should mean that U3 is shorted but I have no clue what chip that is and I don't know what to order to change it. On the chip it says ACMG(if I saw it well) but google doesn't tell me anything. I don't have a clue what my next step could be, where to order that chip. I have your clue that it is a 3.3V regulator so I am searching some sites for something similar.

C20 and C23 are both 10uF ceramic SMT Caps, 0805 size. Voltage rating for the replacements should be 6.3v or more. You could put anything from 10uF to 100uF in there and it'll be fine for a replacement.

If you want to know every capacitors value, you'll need a cap checker, a 100% working controller to remove cap by cap and a pile of time to absolutely waste documenting it all, and then it would mostly only apply to that version of controller.

They are just for decoupling (DC filter caps) so remove them both and power up the controller to make sure everything still works fine, and if it does then replace them. If it still acts up, it could be U3 is bad, L4 is damaged or pretty much anything on the controller, as that U3 regulator is the 3.3v source for pretty much everything on there.

[jasaleja]

Found your answer to one user. U3 is MP3414.

[RDC]

Yep, that's it. But that doesn't mean that it is bad. There could be something else shorted or loading down the 3.3v rail of the controller. As I said, that thing provides the 3.3v for pretty much everything on the controller, so U3 could be bad, or almost any other component that is connected to the 3.3v rail could be bad.

If you have a decent benchtop PSU, I'd remove U3, then inject 3.3v onto that rail and see what the current draw is (make sure both boards are connected) before replacing any parts. Could be U3 is bad, could be some cap on the MCU board is also shorted or all the way up to the MCU bein fried, no way to tell without doing some more checks.

[jasaleja]

I don't have a PSU, sadly, but I will devote my time and check every CAP if it is bad. 

[RDC]

Ugh, that's the last way you'll want to skin that cat. If you have a DMM, set it to Ohms and see what the Resistance from the 3.3v rail to Ground is on the MCU board. Unplug the boards and just check the MCU board, pin 4 of J5 is the 3.3v rail, then you can use any ground spot, accessory connector, stick housing, etc.