2022-0-22

JHEMCU GH743 AIO (whoop) 40A 3-6S    >>>   5 Volt Regulator Issue.

In the past, I have had very good success with JHEMCU products, particularly
their whoop AIO Flight Controller boards. Therefore, I had no problem ordering
two of these new boards. The ratings on this board are what I was looking for
to go in my Rescue Quad build which is running 2407 1850 Kv motors.

I installed the first FC and thought that I was testing things as I went. The XM+
receiver powered on {when plugged into the USB} and the motors were all
working when the battery was plugged in. After the quad was completely assembled,
it was taken outside {yeah, this is a big 7 inch} for a hover test. Connected the battery,
but I knew something was wrong since I didn't have any power on the receiver. Yep,
no way to arm nor control this thing. Back on the bench, there was no power on the
5 volt rail. {at least not on the receiver}. I installed a 5V BEC on the receiver, but not
on the rail. Outside again. This time I didn't hear all of the correct "beeps" when the
battery was connected; tried powering the entire 5 volt rail which seemed to power
that circuit, however, still NOT getting the beeps from the ESCs, nothing. Bummer. 
Since I don't FIX electronics at the board level that was it for the first FC.

Recall, that I have two of these boards so I just dismantled the quad and replaced the
FC with its twin sister. Now, I am testing everything as I go...literally. Low and behold,
there is no power on the 5 volt rail. Ok, now I install the 5V BEC onto the 5 volt rail.
I just spliced it into the receiver power wires. Test again. Now everything appears to
work and I get all of the correct "beeps". Take her outside, connect the battery, all
"beeps" sound normal, the quad arms and the motors are spinning, lift off. WOW,
She Flies !!!  

Since the issue of having a bad 5 volt regulator presented in both FC boards, I now
believe that the problem is larger than just one or two boards. I suspect that there 
is at least one batch of the JHEMCU GH743 AIO 40A 3-6S boards out there with 
bad 5 volt regulators.  

Even though my solution of powering the 5 volt circuit with an external 5V BEC worked,
one should not have to do this on a new FC especially at the current cost of these boards.

If anyone out there has had any experience with the JHEMCU GH743 AIO 40A 3-6S
FC, then PLEASE chime in and add your comments. Good or Bad. 



  

Apart from a bad batch of components which is probably not directly the manufacturers fault, there are horror stories of a few instances of recycled components and even components that never met the QC/Inspections at the time of manufacture.

Fairly common with capacitors, resistors, inductors, voltage regulators, diodes, MOSFETs etc.

I do not want to point fingers at JHEMCU but clearly they are cutting corners to keep their costs low? Unless someone want to prove to me that other are marking up their prices much higher?

Once bitten twice shy. But you have been bitten twice now.

I have no personal experience of JHEMCU products but I've read enough reports of problems with their products that like with iFlight electronics it is one manufacturer that I have purposely avoided buying products from. The only reason some of these budget electronics can be sold for the price they are compared to other manufacturer can only be due to sub-standard electronic components used in a design likely done by junior/trainee engineers, and with no real post-manufacturing QC process. As the old age saying goes, buy cheap, buy twice.

Lets looks at some detailed analysis of real vs fake components:



Beyond the reach of most hobbyists to do such tests but it does raise an eyebrow towards anyone producing cheaper hardware for FPV.

Yeah, I guess I was bitten twice...but I bought them on the same order so 
at least I saved on the shipping. Ha, Ha. 

Now, I am going to stay away from JHEMCU FCs for the foreseeable future.

I haven't totally given up on them, but will wait out this "chip shortage" 
for sure ...AND... certainly will NOT buy that particular FC. 

I want to like Flywoo, but I seem to have issues with their FC boards
and I really don't know why. Oddly, I have had better luck with BetaFPV
FC boards. Also, the HIFIONRC boards that I have gotten are all working
well. Go figure.  All of the GEPRC flight controllers, both whoop and 16x16
stacks have been good with no problems. Who knows ??

i had three jhemcu 1-4s 30a f4 aios.
i thoutght i burned the 5v regulator on my first one and was annoyed until i figured out cam? vtx? as source (dont know it anymore. that was on 4inch 4s 4000kv.

i was surpriced by that aio ratings and liked to test their full ability; i builded a plus quad with xnova 2207 2450kv. it holdup well until my buddy flew and used turtle mode.
as turtle mode does cause high spikes, it wasnt as good as regular stacks. it performed well for racing, it performs.

i flew one on a 4inch cinewhoop with 2206 motors, actual i use this one on that 2206 engines on 5inch.

there was allways a need for additional capacitance on that aio, 1000uf 35v regulary.

i would buy it again ln the 30$ price, it wasnt just small and had good specs, it was also the most inexpensive option on that a rating.

the buddy who burned my aio with turteling flew many jhemcu products seems than; the 40a f7 -stack- is used on an a racequad.
some 40a escs are used on his x8 paired with a matek h7 fc.

while i wouldnt thrust fully in their rating, special on aio boards - all did holdup well in stresstests exepting the one on 2207 xnova and turtlemode.
i like jhemcus value for money.

Hi Bat,

Yeah, I agree that the JHEMCU boards are cost effective; good value. I have used them in the past
with good success. That is why I didn't mind picking up two of them. These are the first ones that I 
have had any issues with. I will say that the very tiny pads behind the DJI connector are a real PITA. 
It is almost like they don't intend for you to use them.

As for the capacitor, I use a 1000 uf 35V on pretty much all of my builds that are bigger than 3 inch.

while i didnt proofed it without, special on that particular aio board i used, an additional 1000uf 35v was suggested on bigger engines/rotorsize.

in theory it should work without, its also not truly proofed but all aio boards got my attantion with a cap. i use a few 4in1 escs without an additional cap, trust them more.

sad you got that experience, as snow told it might be the risk on calue for money parts - their production is focused on the attraction of price, that might go wrong sometimes.

overall my personal rate for jhemcu is still higher than on iflight parts. i order them into hglrc, eachine, ... all the old known value for money shenzen brands.
i use them for bashers quads, fun racing, but i wouldnt mention them for a lr rig as example or on any racequad for the use to win a competition.

More to this saga...

During the maiden FPV flight of Rescue-1, there was an issue with one of the motors.
Ok, it is either the motor or the ESC. Back at home, swap the motor with its diagonal
mate. This issue stayed with the location, NOT the motor. My conclusion here is that
one of the ESCs is going (or gone) bad. Now, this board is quite similar to the first one.


Bad 5 volt Regulator...AND...Bad ESCs. 

I bought the JHEMCU Play F4 Whoop AIO for a NanoLR.

It was nothing BUT trouble and I firmly intend to never buy another of their products.

All my JHEMCU GHF405 35A and the original GHF411 30A (after replacing a shorted FET) are going strong.

Both HifionRC F7 40A working, although I had to fix emf detect circuit after crash chipped the resistors.

I have almost like 10 AIO FC, and almost all the <20 amp, eventually fried.

I had bad luck with both Flywoo and both iFlight AIO FC.

Well.. that was June.

Now 4 boards broken
GHF411 - Geprc1204 smoked. replaced 2 FET. motor m1 again.

GHF411 on 4". - no boot led. replaced F411 from donor board.. seems ok now.

HifionRC F7 - no idea how this happened. Landed in sandy patch. SOT353 super hot. Pulled F7 off and 3.3V short is gone.

GHF405 - Possessed by demon

More on JHEMCU....

As I began work on the GT-LT6-X1 build, I decided to use a JHEMCU GHF405 35A 
AIO (whoop) board that I have had in the parts bin since before the chip shortage. 
The first time that I plugged the USB cable into it for basic configuration all was good.
The next time that I plugged in the USB cable...NOTHING... No lights anywhere. 
Bummer. Since I am working on two quads, I will put this aside and try to debug
it later. If it is just the 5 Volt regulator, then I may be able to use it in something
later on. 

So far, the JHEMCU GHF722 30x30 board that is currently in the Rescue Quad 
is still working.

For me, the JHEMCU now has the worst success rate {more failures} of any brand 
of board that I have used. 

The Flywoo boards have not been very good either; both in the BNF and FC boards.

At this point, the HIFIONRC, GEPRC, iFlight, and even BetaFPV boards have worked
fine and have (cross my fingers) not yet failed. Overall, the HIFIONRC has been the
best performing and best value FC boards that I have used. Right now, this is my
brand of choice.