Servo Shutdown
09-01-2003, 03:04 AM
#1
Junior Member
Thread Starter
My Feedback: (3)
Join Date: Apr 2003
Location: Dallas,
TX
Posts: 10
Likes: 0
Received 0 Likes
on
0 Posts
Servo Shutdown
Anybody out there give me some insight as to why my servos are not responding?
I have 4 JR 811 digital servos and a Futaba 9253 running off a 4.8 v/1400 Mah JR battery pack through a Futaba 138DP rx. I have a multimeter that I can measure output in Volts but not Mah as my meter only goes to 200Mah I believe.
The Volts check at the battery, the receiver pins for the servos on the rx, but I am getting no power to the servos that I can tell. I don't want to short out the servo by sticking the probes inside the servo and don't want to poke holes in the wires of the servo(unless I need to).
Is there something I am missing, or should I take them to a shop to be looked at? Unfortunatley I have no other radio equipment to try and test them.
Thanks in advance for any help you can provide
Scott
P.S. Yes they were working the last flight
I have 4 JR 811 digital servos and a Futaba 9253 running off a 4.8 v/1400 Mah JR battery pack through a Futaba 138DP rx. I have a multimeter that I can measure output in Volts but not Mah as my meter only goes to 200Mah I believe.
The Volts check at the battery, the receiver pins for the servos on the rx, but I am getting no power to the servos that I can tell. I don't want to short out the servo by sticking the probes inside the servo and don't want to poke holes in the wires of the servo(unless I need to).
Is there something I am missing, or should I take them to a shop to be looked at? Unfortunatley I have no other radio equipment to try and test them.
Thanks in advance for any help you can provide
Scott
P.S. Yes they were working the last flight
09-02-2003, 02:01 AM
#3
Junior Member
Thread Starter
My Feedback: (3)
Join Date: Apr 2003
Location: Dallas,
TX
Posts: 10
Likes: 0
Received 0 Likes
on
0 Posts
Fixed!!!
I did just that and found the radio in PPM, not PCM. I recycled it and everyhtiing came back online. Guess I still don't completley understand, but we're back up and running. Appreciate the info....now I don't have to throw it away and start over.
Thanks very much,
Scott
Thanks very much,
Scott
09-02-2003, 05:51 AM
#4
Senior Member
Join Date: Sep 2002
Location: Rochester,
NY
Posts: 1,373
Likes: 0
Received 0 Likes
on
0 Posts
Servo Shutdown
Be VERY carefull when sticking multimeter leads into an RX. Even with small leads it's very very easy to accidentally slip and jam the lead inbetween the VCC and servo signal pins, and on most RX's you do this more than for just a micro second and you'll fry the output drive to that servo (the channel dies)
09-02-2003, 03:02 PM
#5
Senior Member
My Feedback: (2)
Join Date: Jan 2002
Location: Tuscola,
IL
Posts: 2,636
Likes: 0
Received 0 Likes
on
0 Posts
Servo Shutdown
Scott,
Your receiver is PCM. your transmitter must be in PCM to talk to it. If it is not, the servos wil not respond at all, as the signal is not in its language. The job of PCM is to completely ignore any input that it gets that is not in its particular language, assuming it is garbage, and it holds the servos in a preset position until it hears good info again.
does this help?
Your receiver is PCM. your transmitter must be in PCM to talk to it. If it is not, the servos wil not respond at all, as the signal is not in its language. The job of PCM is to completely ignore any input that it gets that is not in its particular language, assuming it is garbage, and it holds the servos in a preset position until it hears good info again.
does this help?
