Hello, i have another problem with my APM. I suspect i have a fried MUX, here are my symptoms :
- Everything was working fine for an arduplane, i was thinking of making an arducopter.
- I think i've plugged a radio output into an APM output at some point (damn these cables all look the same) Since then i've observed the following problems :
- All radio input channels are to zero exempt channel 2 which works fine and channel 8 which is blocked to 900.
- My radio is working fine (tested with a servo)
- The Mux and Power led are Full-on, the PPM led blinks quickly (seems normal isn't it?)
- I've tried to put the arduplane again in it, restart from scratch and it does the same thing again and again...
Do you think my APM board is fried ? do i need to change the red board only ? Is there other things to test to have a more precise diagnostic ? is it possible to revive the MUX ?
thanks,
Replies
where i can buy this chip(74ACT157D) , i can't found in local store :(
need sugestion
thanks :)
Little update on my case : I've reflashed the 328P with an AVRDragon programmer, went fine. I've reset the EEPROM of the ardupilot, and after many tests, here is the status :
I think i will have to declare my APM red card dead at some point... :/ any new ideas ?
Hi guys well apparently our board (marianne is my groupmate) seems to have a fried mux. I salvaged a working 328p from our 1280 board and the now the ppm led lights up already and I can see the pwm getting in already through the CLI. But unfortunately there's no output; I mean the servos doesn't move at all, I tried connecting the servos directly to the rx to see if its ok and yeah, it is ok so that left me with the idea that the mux is indeed fried.
Can I just buy the mux chip(74LS157D) and replace it directly? I mean does it need to be programmed like the atmega328p?
and oh, the apm doesn't power up when powered through the rc rail. So I tried powering it externally and unsoldering SJ1. Yes the apm powers up, but it can't read the pwm signals from the rx. Funny thing is, when i tried putting a jumper unto Vin( external voltage input to apm;beside SJ1) from the rc rail, viola, it powers up AND reads the pwm signals from the rx.
Hmm guys any ideas why this is happening? busted diode between the rc rail and internal vreg perhaps?
It's kind of hard to damage the MUX chip, the atmegas are pretty hardened, unless you've applied > 5v to it, and you shouldn't be able to do that with the power coming from the radio. I've shorted my input many times before by plugging in the jst plugs upside down.
You mentioned that you were running arduplane and now switched to arducopter, did you remember to reset the eeprom? The old settings may be making arducopter go nuts.
Also unplug all the radio input and only plug it in one channel at a time to figure out which channel on the APM may be bad.
small update : i'm waiting for the programmer to arrive to reprogram the chip...
Marianne> what happened to the boards since ? have they magically worked again ?
If the MUX has been fried, it would need to be replaced, but since the MUX and PPM lights are on, it sounds like the board may not be fried. Did you say that you've reloaded the same arduplane firmware that you had been using before the problem with the channels, and that the problem has persisted? You can try reflashing the 328 chip and see if this helps: here are instructions for how to reflash the chip here in the ArduPlane manual. Hope this helps!
nobody has a clue for me ? :/ thanks,