If you try it and it does not work then all you need to do is PM and ask to re-activate the code. The worst they can say is "no" but the philosophy is usually sell, sell, sell.
Heres the link for the new GB.
greate
thanks 
Anywhere i can download the manual for the C3100/C3400?
thank you, link worked.
How about a new coupon code from Gearbest for the Opus C3100 4.2 version.
+1
Is the 7.4 version out next month?
i think the most current version is the v2.3 firmware
Today, my BT C3100 V2 slot #3 is malfunctioning - reading higher cell voltage than actual - remove cell from slot, lcd still reads last value displayed - will not clear until power plug is removed.
Tested cells in my Xtar VP2 to verify misreading of BTC3100 V2.0
Anyone else have this anomaly happen with your charger?
My unit died this week.
What is the best replacement.
How’d it die?
I was charging my Eneloops and I came back and it won’t power on now. Maybe the Power Supply died but this was v1
My Vapcell S4, Miboxer C4-12, and Eizfan Lux S4 has the same 12v power supply output voltage and barrel connector, and in fact, to most other brands of chargers.
Nice, I’ll check if I have another power supply but I don’t have a 2nd unit or alternate chargers like your collection.
I qas thinking of getting a charger that can also do RCR123A for Arlo cameras, and read that the BT-C3100 v2.2 can do it.
Unless you don’t have a multimeter, checking the power supply should be fairly easy. All these years later, this is still my favorite charger. So I wouldn’t throw it away if there was a chance a $5 wall wort would get you back to working. I thought there was a replaceable fuse on the board also, that I saw while replacing the fan, at one point.
Arlo’s eat batteries. I printed my neighbor some new bottom covers that allow access to the usb plug and he wired them up to cell phone chargers.
I have a multimeter, but cant locate it! Moved recently!
I managed to pick up a MOSO Switching Power Supply rated at 12v 4A (model MSP-Z40001C 12v-48W) and managed to score it for A$4.
It got me going again!
But my fan mounts were broken and the fan is not running. I have to test that and find the fan mod that people talk about on here.
Also have to find the difference between v2.0 and 2.2.
Put the charger on top of one of those cheap laptop cooling base fans.
My first Opus broke one of the fan mounts and I just used a toothpick as a splint and glued it on there after aligning the fan to proper position and it worked fine.
Think FastTech may have replacement fans real cheap as well, they are just a little thicker so you have to cut housing slightly.
HTH
Later,
Keith