[califrag]

WOW!! OK I've figured out the problem....

It looks like the IR LED for my Battle system was wired up polarity REVERSED

Here's what I did to test...

First, I tested a TSAL6200 with a 3V CR2032 cell battery to verify the "long lead" was anode\+ and short was cathode\- and I could see the TSAL6200 IR LED with the camera on my phone.

Next I unplugged the Tamiya Battle System IR LED from the MFU and shoved a couple wire jumpers into the connector. The IR LED connector wires were Red on Left and White on Right respectively.

> (Stock) Red on Left White on Right_s.jpg
> MFU Connector Red Left White Right_s.jpg
> IR LED with Jumpers_s.jpg

Using the 3V CR2032 cell battery, I was able to verify the IR LED still worked with Red (Left) being anode\+, and White (Right) being cathode\-.

> IR LED CR2032 Red Positive White Ground_s.jpg
> IR LED CR2032 Red Positive White Ground Jumpers_s.jpg

I had downloaded a wiring reference diagram for the MFU previously and referencing it showed that the "Right pin is +" for the IR LED connector on CN2

> Tamiya MFU wiring.jpg

So this was the first indication that something was wired up wrong!

I plugged the Tamiya IR LED back into the CN2 socket and then just jammed the TSAL6200 legs into the molex connector of the TBS IR LED, with anode\+ on the RIGHT as per the wiring diagram. Sure enough, when I pressed the cannon button, I could see the TSAL6200 light up on my phone camera!!

Only thing left to do was to swap the Red\White cable of the molex connector for the Tamiya IR LED and test it with the TankIR.

It worked! When I pressed the cannon button on my radio, I could see the Tamiya IR LED light up on my phone camera and when I tested it against the TankIR on Arduino pro mini (compiled from 2.3.7 with low memory warning etc etc) it registered the hit from my tank first try.

I think it's pretty crazy that this IR LED was wired up wrong but all evidence points to it having been reversed.

It's also kind of odd because the color coding of the cables is inconsistent, for example the cable for the lighting system in CN5 has a Blue\White cable, where White is on the Right (+) and it works fine. However the MG in CN3 has White\Orange with White on the left and Orange going to +.

Triple checking with the product page on the Tamiya website the photo of the product shows as the correct wiring with Red toward what would be the Right of the connector when plugged in looking from the front of the MFU, so it would appear that mine is soldered correctly to the legs of the IR LED but just was assembled incorrectly into the molex

https://www.tamiyausa.com/shop/116-tank/rc-116-tank-led-battle-system/

[LukeZ]

Well that's quite the mystery you've solved! These are always the hardest problems to figure out because we naturally don't think to consider that Tamiya would have made a mistake like that, and instead we go looking all over everywhere else.

I have always seen the red wire on the right side of the connector as the DMD documentation you found confirms. On the Open Panzer downloads page you can see a picture of the Tamiya Adapters where I also had the red on the right. So yeah, someone made a mistake in the factory somewhere. It's fortunate that the LED didn't get burnt out from having reverse voltage applied to it! 

Anyway I'm glad everything's working now and thanks for posting all your findings. Hopefully this doesn't happen to anyone else but if it does we now know about it.

Merry Christmas Eve!