Problème UV elegoo saturn

[Shun]

Bonjour à tous j'ai un problème sur la saturn, le nid d' UV reste allumé constamment à faible intensité ce qui fais chauffer l'écran extrêmement vite, en gros ça catalise tt le temps.20220718_174856.heic

[PPAC]

@Shun Salutation et bienvenus sur le forum !

(A l'avenir, pense a convertir les fichier .heic en un format plus générique avec par exemple https://convertio.co/fr/heic-jpg/ histoire d'avoir plus de vus et d’éventuelle réponses)

A tu déjà regardé https://blog.honzamrazek.cz/2021/06/fixing-the-backlight-always-on-problem-on-elegoo-saturn/

( lien trouvé sur un groupe Facebook ( il me semble que c'est ELEGOO SATURN JUPITER FRANCE ) Qui explique que cela peut venir d'un Mosfet sur la carte mère et qu'il est possible si tu a les compétences et le fer a souder qui vont bien d'en utiliser un autre (mosfet) qui se trouve sur la carte, mais non utilisé ... ) 

Citation

The symptoms are that the UV backlight is always on. Elegoo has been really helpful and it seems that when a user reports the problem, they send a replacement mainboard.

I was wondering what causes the problems, so I reached out to a few of them if they would be willing to send me the broken motherboard. One of them did (thank you!) and I started to investigate what’s wrong. TLDR: The fix is easy and costs you nothing if you know how to solder.

What’s wrong?

The LEDs are driven via a boost converter that outputs a constant current. This driver is located on a separate board. There are actually three of them – one for each array of LEDs. The turning on and off of the LEDs is not done via pulling an enable pin of the boost convert driver IC but there is a dedicated MOSFET on the mainboard, that switches the power for these boost converters. You can find them on the photo below (it is the left-most transistor). I also attach a schematics of the connection:

The right-most transistor controls the LEDs

The schematics of the switch circuit

After measuring the transistor the problem is clear – the transistor is dead. It is shot-throught and it is always conductive. I have also confirmed this after removing the transistor.

How to fix it? Replace the transistor. Luckily, the manufacturer gave us a spare transitor. The middle transistor is not used for anything, therefore, we can desolder it and solder it instead of the broken transistor. Easy-peasy.

Swapped transistors. Note that I wasn’t carefull and I broke the gate trace. This is why I replaced it with a piece of wire.

After swapping the transistors, the board works again!

 

Sinon au plus simple, changer la carte mère. (donc demander au SAV de Elegoo https://www.elegoo.com/pages/support si encore sous garantie ) 

 

Tiens nous au jus et bonne continuation.

Modifié (le) Juillet 18, 2022 par PPAC

[Shun]

Merci énormément tu me sauvé la vie, je vais essayer ça.