Where did I go wrong?
 

After installing a servo the correct way, I realized that I needed to reverse the servo on my transmitter to get the servo travel in the right direction. As my luck would have, the servo reverse switch didn't work. So still in need to reverse the servo, I decided to go old fashion and reverse the wiring by cutting the wire, switching, and solder back together. Here's my problem, the servo worked fine before, but now is unresponsive. Could I have ruined it by mistakenly switching a power supply with a signal wire? Is what I was trying to achieve even possible with newer servos? Any advise will be appreciated.

RE: Where did I go wrong?
 

What you did is impossible with any servo that I'm aware of. Put the wires back where they started. You may or may not have ruined it. You could have shorted your receiver in the worst case. You have a few options:
First, obviously, get a radio that works. This will be the most expensive option. However, if the reversing switch is broke on the radio, what else is broke? Is it even safe to use?
Second, get a reversing Y for about 10 bucks, and hook the servo up to the reversed side of the Y.
Third, get a matchbox for about 70 bucks.
Fourth, hook the pushrod up to the other side of the servo--may or may not be possible
Fifth, get another brand of servo that operates in the opposite direction.
Sixth, set up a series of bell cranks that would reverse the travel of your output.
There are more options, use your imagination and modeling skills. I assume you have some modeling skills, since you know how to go "old school."

RE: Where did I go wrong?
 

I use Futaba and Hitec servos and reverse them the same way, by reversing the red and green wires on the potentiometer and the orange and brown wires on the motor. I never had a problem doing this. You can go to the Hitech website and go to "general servo frequently asked questions" to see a diagram. I would like to upload it with this reply to share with everyone, however, it is a PDF and I cannot upload that type of file. I can PM it to you if you would like. Hope this helps.

Steve

RE: Where did I go wrong?
 

The setup in this small plane made it impossible to switch anything around, no room, not even the other side of the servo. On the other hand, the transmitter switch was not broken, just my foolishness. I just plugged it into the wrong slot on my reciever since I was only checking the operation of the servo. I was using the wrong reverse switch for a diiferent channel. As I said it was my stupid mistake that I had overlooked and assumed too soon that the switch didn't work (I didn't mention this because it isn't important to what I need to know). I use the reciever currently in that plane, works fine. Just put in a new servo and used the correct switch this time! However, my problem is that I have a brand new servo that does not operate, a shame. Is there something that I could have done while rewiring that shorted out the servo internals? I have checked all internal leads and connections and all seam fine. Even when putting them back to the original order, no difference. Any additional thoughts?

RE: Where did I go wrong?
 

If the servo is not working at all after your repairs, you have 2 choices. Send it back to the factory for repairs or cut your lose's and toss it in the garbage can and replace it. Good luck, Dave

RE: Where did I go wrong?
 

send the servo and tx in for service since the reversing switch is not working per your post then there is a problem that could cause more problems.

RE: Where did I go wrong?
 

As stated in my 2nd response, the transmitter was fine from the start. My error led me to believe that it was malfunctioning. Also, it is not worth the money that the servo is worth to bother with sending it in for service (its a standard Futaba 3004). The way I see it is if you guys might have had the same trouble, there might be a quick fix. If I can fix it fine, if not its trash. Just hated to toss it without asking the pros first. My thoughts is that it is a standard servo, not digital, that has all electrical and mechanical components that someone with any background in either could easily visualize the problem. For example, if someone told me that they suspect a resistor might be bad then I could easily replace it. Or maybe even advise on what to look for to find a short, etc. I guess I am digging for a solution because I enjoy tinkering with gadgets, it would be an enjoyable challenge to try to fix it. I understand that the info that I have supplied is limited, please forgive me. Thanks for the advise from everyone.

FYI, Rest assured that I would never endanger anyones life by using this in an aircraft after me tinkering with it.

RE: Where did I go wrong?
 

I suggest that you keep the servo - even if it is junk - anyway. Start a box marked "Bad Servos". These can then be used as dummies for setting up planes in the future (cutting mounting holes, etc.) and the gears can be used for replacement of gears on othedr servos that go bad - as some will. On other "Bad Servos" where the electrical lead is still good these can be salvaged for future hook ups as well.

RE: Where did I go wrong?
 

Just switch brands of servos; Hitec and Futaba turn in opposite directions with the same input. To change the direction of a servo, you need to modify its innards, switch the two outside wires on the potentiometer and switch the two wires going to the motor. If you interchanged the positive and negative leads on the servo you tried to modify, you most probably smoked the servo innards. If it was the positive lead and signal lead you reversed, no damage should have occurred, just switch them back and see if it now works.

RE: Where did I go wrong?
 

The brand of servo has nothing to do with my problem. I will restate it to make it clear.

I have a servo that does not operate after cutting the 3 wires and reordering them trying to reverse the throw. Even after putting them back to their respective original lead, no response. Something happened when I crossed the wiring. Is it salvagable by a repair or is it garbage? Does anyone have any clue as to what I could check that I could have shorted out or destroyed in the internals?

The specific installation that I was talking about needing to reverse the servo intially is insignificant to my problem. My transmitter and reciever are insigificant. I have done this before so I know it is possible to reverse the wiring to reverse direction of travel.

RE: Where did I go wrong?
 

IIRC, the internals of the S3004 are all surface mount (you have burnt something out here) now if you are professional quality at soldering then you can replace them. Things to look for, first when you reversed the wires was there a smell coming from the servo, for instance when you blow a capacitor it smells like rotten fish, second look for burning on the inside of the case and then match up with the servo internals, last look at the internals for the same burnt marks. If you can local the component that is burnt out (it could be the tracks) then with a magnifiying glass take the details of the component and do a web search for the type and rating and attempt to replace. If you have damaged the track then you can simply apply solder across the break.

HTH

James

RE: Where did I go wrong?
 

r2Champion, it is impossible to reverse the direction of throw on any modern servo by changing the leads outside the servo itself. If you think you succeeded by doing so, your memory is failing you. If you have restored the leads to their original order and the servo does not work, you have destroyed one or more components insided the servo.

RE: Where did I go wrong?
 

Rodney, as you will see in my original question I asked if it is even possible to do this with newer servos. Thanks for answering that question for me. I have in fact done this with an airtronics servo that is years old, hence the reason that I asked that question to begin with. Additionally, I realize that I might have destroyed some internal components as you have stated. Any ideas on what components or am I fighting a losing battle on trying to find out. I am hoping someone with some electronics knowledge will know the internal setup of an analog servo and know what would have been destroyed (if not all), and atleast give me a starting point.

RE: Where did I go wrong?
 

HI
to change the directions by rewiring you have to reverse the wires on the motor and also on the pot change the outside wires only on pot. another solution would be to just turn the servo 180 degrees, but reversing at the transmitter should have solved your problem
if you reversed the wires from the servo to the plug you have applied reverse polarity to the circuit board and probably blew the electronics.

as stated above the wiring changes are made to the internal wiring of the servo.

good luck and happy flying

pt19 flyer