Repair IMAX b6 ac - Page 1
Forum section: electronics / repair

author: nnannos
author_rank: Contributor
timestamp: February 15, 2019, 08:11:57 pm
content: I have a IMAX b6 charger with ac, after USB in(micro USB connector) short circuited smoke was seen and now is dead. Can cpu be dead? can I put firmware externally with programmer on another CPU?

author: nnannos
author_rank: Contributor
timestamp: February 16, 2019, 09:08:33 pm
content: Has ever anyone programmed a CPU with firmware externally and then put it on a circuit?

author: Whales
author_rank: Super Contributor
timestamp: February 16, 2019, 10:25:27 pm
content: "short circuited smoke was seen and now is dead"Programming new firmware can't fix a blown part. You can't reprogram a car to work after the engine has exploded. You need to open it up and find exactly what has died, don't guess it's the CPU until you have seen it, and even then it's probably only the victim (not the cause) of the problem.To answer your question: it depends on the model of microcontroller ("CPU"). Some are easy to program, others are not.I tore apart an IMAX charger years ago. It had horrible build quality: mosfets that needed to be heatsunk were floating by a small air gap off the case, soldering was a mess and the in-built power supply (this model had one) was a deathtrap hiding in a laptop charger case. I think it claimed crazy amounts of amps, but inside was missing most of its components and the ones it did use were under-sized.Beware: these things are not made to last. Never use them anywhere near their claimed charge currents; and never leave them unattended.

author: Whales
author_rank: Super Contributor
timestamp: February 16, 2019, 10:29:15 pm
content: Here we go:https://www.eevblog.com/forum/reviews/fake-imax-b6ac-charger-teardown-advice-sought/msg609391/#msg609391Looks like there might be better quality ones and bad ones; but there's no way of knowing without opening them up.

author: nnannos
author_rank: Contributor
timestamp: February 17, 2019, 10:23:20 am
content: I mean to replace blown part with new and put firmware inside, can this work or the CPU has also something else inside besides firmware, other parts blown also will be replaced.

author: Whales
author_rank: Super Contributor
timestamp: February 18, 2019, 09:43:35 am
content: If it's an ATMEGA then it will also have "fuses" (programmed settings, not actual fuses). Read up on using a program called 'avrdude'.Best way to find out is to try it. You won't get anywhere unless you take the charger apart.Obligatory: if your charger has a built-in mains power supply then don't trust it. Unplug it when working on it.

author: gearshredder
author_rank: Contributor
timestamp: February 18, 2019, 10:51:37 am
content: Mine fried. Not sure how. I used my FLIR and set current limit, saw the mosfet got nice and hot. Replaced the dtm4410 with a AO4468 and now it works.

author: SilverSolder
author_rank: Super Contributor
timestamp: February 18, 2019, 03:48:23 pm
content: It's probably not the CPU, would be my gut feeling.Don't turn it on, take it apart! (and post some pics)

author: Mkdsime
author_rank: Contributor
timestamp: February 18, 2019, 06:32:02 pm
content: Yes take it apart and take some pictures especially around the usb and the output maybe and the psu

author: nnannos
author_rank: Contributor
timestamp: February 19, 2019, 06:03:27 pm
content: Quote from: Mkdsime on February 18, 2019, 06:32:02 pmTook it apart, everything looks ok, the USB diodes are ok, now I have to remove the LCD to see under, I think 78m05 ic looks fried at corner, measured voltage there and has 5v at beginning but after 20secs it goes to 1.6v, can a 78m05 get fried???

author: oPossum
author_rank: Super Contributor
timestamp: February 19, 2019, 08:01:38 pm
content: Quote from: nnannos on February 19, 2019, 06:03:27 pmIt certainly can fail, but I think in this case it is overloaded by another failed component and is shutting down to protect itself.

author: abyrvalg
author_rank: Frequent Contributor
timestamp: February 19, 2019, 10:33:25 pm
content: Depending on the actual version of your B6 (there are many clone flavors) it could be possible to use a compatible (and more advanced) cheali-charger firmware:https://github.com/stawel/cheali-chargerOriginal firmware dumps are circularing on RC forums too (but cheali is better IMO).

author: nnannos
author_rank: Contributor
timestamp: February 21, 2019, 01:15:01 pm
content: Found damage after removing the LCD, TD1534 ic is blown(D.C./D.C. Converter) found it on aliexpress only. Does anyone know where to buy electronics ics other than China?

author: james_s
author_rank: Super Contributor
timestamp: February 22, 2019, 04:33:12 am
content: The B6AC is a piece of crap to begin with, I have one I bought back before I knew better, these days I use a pair of thesehttps://www.banggood.com/Charsoon-Antimatter-300W-20A-Balance-Charger-Discharger-For-LiPo-NiCd-PB-Battery-p-1133818.html?akmClientCountry=AmericaI power them from a IBM hot swap server PSU.

author: nnannos
author_rank: Contributor
timestamp: February 22, 2019, 03:31:02 pm
content: Very good charger! I will buy one in future for sure. Thank you for the information, wish I knew it before buying this

author: james_s
author_rank: Super Contributor
timestamp: February 22, 2019, 06:31:26 pm
content: The Antimatter 300W charger is the best bang for the buck that I know of, it was previously sold as the Turnigy Reaktor 300 which was very popular. You can get nicer chargers but not in that price range.