What am I doing wrong?
 

http://www.rcuniverse.com/forum/atta...mentid=2184458

Hi Guys,

Got these 8 pin connectors from emcotec for my rebel pro, so I can have ailerons, flaps, gear and brake on one connection.
Maybe I understood the Emcotec guy wrong or am I doing something wrong.
The + of ailerons and flaps are joined together on one pin and the - of ailerons and flap are joined together on another pin. The signal wire of both are on 2 separate pins.
The + - of gear and brakes are simple.
The problem is when I hook up everything the ailerons and flaps seem to work fine for around 15-20 min then the servos start to gitter.
wires are all new and heavy gauge.

Need help as this is the first time I am going 8 pin.
Thanks.

Chatty.

Yes that is correct, they can share the same positive leads, and the same negative leads, the signal wire for each servo is on its own pin. Your solder connections look great, and the connections must be correct, or they would not work at all. I hate to ask the simple, but,,,are the batteries fully charged
And what servos and voltage to them are you running

I bet those little pins get quite warm after 15-20 minutes?
One point of failure to save 5 seconds plugging in another connection...

Thanks Raron,

First thing charged the batteries after the servos glittered. Batteries are new Liion 3000mah from emcotec, no luck.
Just for test used a 7ch spectrum RX with a PB sensor switch, eventually a PB Mercury will be used.
Thought initially the servo leads may be a bit long, but simulated similar length direct to the Rx bypassing the 8pin connector and all is fine.
servos are JR 8911 and 8511.
scratching my head on this one.

Dave infact that's the 2nd thing I did. Touch the pins to see if it's warm. Stone cold.
The only thing that did warn up a bit was the Sensor switch heat sink.
Of course will go 2nd connection if can't solve the problem, but thought the multiplex pins can handle a fair bit of current.

Are you sure it's not a gyro causing the flutter? They do that sometimes on the ground. Especially if the gain is high.

Hi Andy, no gyro yet. Just testing it on the bench connected directly to a Rx.

If you turn everything off after the wiggle, wait 10 minutes and turn everything back on, does the wiggling come right back or only after another 20 minutes of on time?

Test it without the connector. Bypass it. If it's the connector it will show up. I don't think it's the connector though. Multiplex type connectors are usually rock solid.

You said you have long wires? I've got long wires in my 1/4 scale L39 and never had a problem like that and the wires I used are not twisted.

OK, then try a different Rx. Is it an old type Spekky 7000 Rx?

Dave

Could it be a large voltage drop due to running 2 servos in parallel? Maybe thats why it is working with a higher voltage (6.6v) supplied by an LiFE pack, rather than the 5.9v supplied by the PB sensor switch?

[QUOTE=Dave Wilshere;12264565]OK, then try a different Rx. Is it an old type Spekky 7000.

Dave.. your a Genius. How did you guess? Had 100s of flights with this Rx on my funjet. Does this Rx have a problem?
http://www.rcuniverse.com/forum/atta...mentid=2184530

Ragz, same problem with direct Life into the Rx.
Will try a different Rx as Dave suggested.

http://www.rcuniverse.com/forum/atta...mentid=2184624

Guy, changed one male connector on the servo end and problem seems to have gone.
Broke open the male Muldental connector from Germany and found the pins are soldered not crimped, is this acceptable? Or should I just go ahead and crimp all male ends.

Thanks for all your inputs
Chatty.

I have had issues with soldered signal cables in the past - soldered postitive and negative no issue but soldered signal cables I have had issues. I can't explain it, it doesn't make sense to me but since then I always avoid soldering signal cables and use crimps instead. Presumably there are hundreds of guys on here that have had no issue with soldered signal cables though so maybe I did something wrong or used the wrong solder or whatever. For dummies like me crimps work pretty good.

A signal lead always has at least two soldered joints - at the Rx and at the servo, so solder is not in itself a problem. I have made many extensions by soldering and not had a problem.

Soldering itself has been no problem. What I am asking is if it's ok to have a servo connector pin terminate with a solder joint rather than a crimp, just because of the surface area and point of contact being reduced

Eletrically solder is better than crimping since the metal is all amalgemated together. The caveats are that the soldering must be done correcly. Otherwise you will get a bad joint.
Secondly you must provide strain relief to a sloder joint as flexing of the conductor can cause failure.
John

A good solder joint is electrically superior to a crimp. A cold solder joint is a source for a potential intermittent connection and/or a high resistance circuit both of which you could be experiencing, as well as other problems. A cold soldier joint typically can NOT be seen. Use an Ohm Meter across the connections to measure it or put a voltage across the connections. If there is a voltage drop across the connections there is an electrical problem with the connection.

To test a Rxer, put a Servo tester capable of reading Rxer resolution output on the Rxer's output on the affected channel. If the Resolution is not rock solid with no Rxer input from the transmitter, then the RXer is good. If the resolution does not smoothly transition as the transmitter moves the channel, then there could be a transmitter or Rxer problem.

To watch the voltage at the load, plug in a Y down by the Servo. Plug in a Voltmeter in parallel with the servo. Using the transmitter, Move the servo and see what kind of drop you get. Also, if there is a voltage issue at idle over time, this too will show up on the voltmeter located at a load.

The only time I have had digital servos start to act up when they are in parallel is when the voltage got too low.

While I agree that a good solder joint is electrically superior to a crimp, I never solder servo wires as I feel the crimp is MECHANICALLY superior for stranded wires in a situation where they will be subjected to flexing. I've seen several soldered servo wires fail just past an electrically perfect solder joint after being subjected to only minor flexing.

Thanks Guys for all the help, connected everything on the bench with the actual setup, PB mercury and 2 into 3000 mah emcotec lion batteries.
Ran it for over an hour and everything seems rock solid. kept moving the sticks with 2 8511 and 2 8911s connected .
Voltage drop the PB showed only around 0.1 drop everytime i moved the sticks. Except for the heat sink of the 8911s turning a bit warm, all else looked good.

Chatty.

Strain relief, aka hot glue + heatshrink and you won't have any flexing to worry about!

Since I already have no issues to worry about I see no reason for a ten fold increase in the time it takes to make a servo connection.
Since I make every single extension in every airplane I've built over the past 50 years which is probably literal thousands of connections and I've never had one fail I see no reason to change anything. Of course everyone should do things in a way that they are comfortable with but the difference in resistance between a properly soldered connection and a properly crimped connection is so far down in the noise compared to the resistance of a couple of feet of #20 or #22 wire that it isn't worth worrying about.