I am so confused now....

[atcttge]

Ok I guys, seems I lost my electronics knowledge. My mind is a blank. I need your help.

First, how do I know if my HL MFU board has shorted out?

Pic below:



How do I use the device on the left to determine if the board is shorted?

[wibblywobbly]

There are two issues here.

One is, if the board is dead then to all intents and purposes it is scrap.
Secondly, if it is scrap then all the testing in the world isn't going to bring it back to life.

Sure you could put the multimeter into continuity mode, though I can't see that option on your multimeter, and go around the board starting at the + power and seeing where the break is, but that will come to a grinding halt when you get to components that don't lend themselves to continuity testing.

Far and away the easiest way to test an RX18 is to put it into a tank, plug the 8 pin in.
Plug the speaker and volume control in. Is there a hiss, if so then power is getting to the board.
Do the lights come on? If the answer is no, then there is no useful power getting anywhere on the board.
If the lights come on, do the turret functions work? If yes, then power is getting through those circuits on the 8 pin.
Plug the motors in, and try to start the tank, if it doesn't start then most probably the esc's are blown.

Go over the reverse of the board and the topside with a magnifying glass and look for scorched or melted components, in reality you already know that the board is never going to work again, so this is pretty much an exercise in futility as the RX18 has no repair facilities available for it.

If all seems dead, the only two things that you can double check are that the battery is fully charged, and that the on/off switch does not have any loose wires. The best indicator of a low battery is that the lights flash but the tank won't start.

There is always a cause for a dead board, so before you fit a new one check all of the wiring, plugs and solder joints for loose wires and poor soldering. No wires touching bare metal, no bare wires rubbing against metal through insulation etc. If the board blew suddenly, then what were you doing when it did so? Until you know why the old one blew, proceed with caution when installing the new one.

A faulty power switch, or solder allowing the +/- terminals to touch is probably the most popular way to blow an RX18 in two seconds, as they don't have any circuit protection built in.

Sorry to be the bearer of bad news, but the tank is the best diagnostic tool for an RX18, as either it works, or it doesn't.

Rob

[BarryC]

Without a schematic and test point voltages troubleshooting with a multi meter is a shot in the dark. Though you may find voltage how will you know if it correct?

Starting at the point where power is introduced you can check voltage by following the traces on the front or back side of the board until you loose it. However at that point unless you see a damaged component it is unlikely without the schematic you will be able to determine what has failed.

Rob's suggestion is the best approach.

Barry

[atcttge]

Problem is that I buggered the switch.

Anyone can take a pic of the switch so I know how it is wired?

[wibblywobbly]

ok, disconnect the battery until it is fixed.

The battery plus and minus go to the two middle pins.
The wires from the board go to either end.

eg

Empty.........Empty
Bat +...........Bat -
Board +.......Board -

HL switches are fragile, anything more than a second or two of heat will melt the internals.
Ensure that there are no solder bridges between any of the contacts.
Preferably put heatshrink over each terminal solder joint.

[forgebear]

[wibblywobbly]

Dave snuck that in there while I was typing

His pic shows the HL solder monkey method, it will also work that way

eg

Empty...Empty
Bat +..bridged across to...Board +
Bat -...bridged across to...Board -

The difference being that you will need more solder and more heat to do it that way.

[forgebear]

yer not the best job
lol but you get the point
dave

[forgebear]

827684208_tp.jpg (7.6 KiB) Viewed 1620 times

this might help to

[atcttge]

Thanks guys. I bought a new, bigger version of the HL switch.

I'll describe my problem:

Because I wanted my mine plow to work, I got from scalawag an HL board. I tried it out with the board connected to the battery and the motor and it worked.

Now, I wanted the HL board to use the same power supply as the IBU2 Pro board.

So wot I did using the original HL sliding switch was add additional wires, connecting the new ones at the same terminals as the stock ones. That way, both the IBU2 Pro and the HL boards will have only one switch, and getting power from one battery.

And so it was time to test. I connected the battery to the switch, I then connect the power plug to the IBU2 Pro and I hear a quick chirping sound with the power light blinking fast, all with the switch on the OFF position.

Sliding it to the ON position results to no light on the IBU2 Pro and no sound. Lest I damage the board, I do not attempt to turn on the tank with Tx.

I thought I might've destroyed the switch when soldering the wires. So I copied the connections but this time using a bigger switch. But I still get the same issue.

No burning smell nor smoke happened when I connected the HL board or the IBU2 Pro. Although I tried hooking up only the HL board but it now doesn't work unlike before.

I also thought maybe my battery is low, so I charge it but still get the same chirping sound and light blinking with the IBU.

I'm stumped.