Trex 150 MRS Board Failure

[jsg001]

It would be from point A to B in this image. Its resistance should be near zero.

This was a picture from a few months ago, and you can see the delamination on the corner of my board (circled in blue).

Step one, if you have not done this, is to plug the tail motor into the main motor socket and make sure it's not the motor.

Step two, with everything powered up measure the voltage on all of the signal pins of the servos, tail esc, and main motor esc (point A or B). They should all be around the same voltage.

Step three depends on how comfortable you are repairing surface mount PCB's.

[alex1560]

Hi.. I think it won't be the case of an easy fix on this. I checked the motor by plugging it in the tail connector and it works fine..

I ordered a new one yesterday... I though I will be able to practice a bit more until receiving the new one... but will do that on the simulator.. but nothing beats the real world...

It's bad because in idle up worked quite well, but when I wanted to land and switched to normal, I was trying so hard to bring it down, and the head speed almost died and he was still too high.. I followed the instructions that I found on the web... but I guess that I need to adjust a bit the pitch and the speed in order to ground it with a good head speed..

Thank you for your help!

[Jazzjohn]

Well, this could be the end of the road for mine...

The PCB at the corner near the negative power lead got delaminated. The pin broke loose so I soldered a jumper on to reconnect it to the ground trace going to the row of 5 chip caps and resistors nearby. Still doesn't work. My symptoms are no servo action and no motor action. There is continuity from the pin to ground and the satellite does bind.

I have since taken apart the three boards.and can't see any other damage under magnification.

Any other ideas?

[jsg001]

Originally Posted by Jazzjohn

Well, this could be the end of the road for mine...

The PCB at the corner near the negative power lead got delaminated. The pin broke loose so I soldered a jumper on to reconnect it to the ground trace going to the row of 5 chip caps and resistors nearby. Still doesn't work. My symptoms are no servo action and no motor action. There is continuity from the pin to ground and the satellite does bind.

I have since taken apart the three boards.and can't see any other damage under magnification.

Any other ideas?

If it were me, step one would be to get the main board (the middle one) working. You said it binds, but the servos don't move. I would start there; getting the servos to work again. At that point the lower board is only supplying power and you can just connect that with two jumper wires or use an alternative bench supply. Check the supply voltage on the board, look for bad solder joints or missing parts, what signals are missing on each servo connection/pin (power, gnd, signal). Double check the connector going to the satellite (maybe go ahead and reflow that connector). I would also try a different satellite (maybe do that first).

I now have a board, donated by osuflyer23, that I am going to strip and create a schematic from. That would likely help in this case. I will post it when available.

[Jazzjohn]

Good points. I see that there's a switching supply on the lower bd and that seems to working and supplying 6 volts to the middle pin of each 3-pin riser. I'll first try powering the middle bd with 6 volts and see if the servos will work. If they do, then the problem must be the lower board.

I had tried a second satellite, but the same symptoms were there.

[Jazzjohn]

Originally Posted by jsg001

I now have a board, donated by osuflyer23, that I am going to strip and create a schematic from. That would likely help in this case. I will post it when available.

Any progress on creating a schematic?

[jsg001]

Originally Posted by Jazzjohn

Any progress on creating a schematic?

Started.... but so has the kid's soccer... It will likely be a week or two before I have something.

[Jazzjohn]

OK, thanks. Enjoy the soccer games!

[irek]

hello I just had a problem with the fets
I do not understand, you talk about fets

post #6
785-1000-2-ND $0.48
785-1001-2-ND $0.58

I was not which is red and which is blue in the picture
red are broken I want to change the three
can you help me to identifier it

[collectiveyedeas]

Can someone please tell me what the small black component is circled in yellow in the attachment I posted?? I borrowed the image from another person who posted earlier in this thread.