Vecchio Austriaco Posted August 5, 2010 Share Posted August 5, 2010 Actually this was an answer to a different thread but I think the better place for it is here. If the servo you are using is an analog servo the job of reversing it is not too difficult. What you need is: No fear to destroy your nice servo The necessary skill and tools to open and close the servo A small electric soldering iron with a pencil style tip plus good quality small diameter solder (no leadfree stuff! - Sorry for the environment guys but my experience is bad) What you have to do: You have to reverse the polarity of the motor and also of the potentiometer. Impossible? I don't think so. Lets have a look at a Hitec HS55 - cheap - if it's broken it will not kill you. It has the value of 2 pints.... After opening the servo you take out carefully the circuit board - there may be a bit of hotmelt which can disturb you (you see the green wire missing a bit if insulation - this is where the hotmelt was... You see here the 3 wires coming from the pot - you need to exchange the position of the two ouside wires - in case of the Hitec HS55 these are the green and the red wire. The yellow one - which is the center one on the pot - you don't need to touch. Done? ok. These were the first 50% of the job. Now we have to change the motor leads. Looking at the motor itself there are 3 wires. Is it brushless??? no - not at this cost. But there is a screen connection between the motor case and the circuit board to avoid interferences. So leave out the wire which is soldered to the case of the motor - this is not our candidate. Take the other two - normally one red and one black - and change their position. Take extreme care not to solder a bridge as the board and the soldering pads are really small. With my eyesight I need a magnifying glass for this job (and no alcoholic drinks 24 h before) Thats it. Put the board back into its original position, close the servo and try it using your radio. The servo I used here for demonstration was happily working on one half of the split elevator of my Seagull Edge 540 EP until I stalled it doing stupid acrobatics with skis on it.... If you have money and therefore use a digital servo: Most digital servos can be programmed (may be you need to purchase a programming adapter or card) so you can reverse them that way. Hope that helpsEdited By Vecchio Austriaco on 05/08/2010 11:02:06 Quote Link to comment Share on other sites More sharing options...
sparks59 Posted August 5, 2010 Share Posted August 5, 2010 Thanks for this Vecchio, a useful and practical post! sparks Quote Link to comment Share on other sites More sharing options...
Erfolg Posted August 5, 2010 Share Posted August 5, 2010 I can see you are an electrical engineer! The mechanical engineers solution is to use the reverse direction on the TX or the dip switch on the the Tx. Simples. Ahhhh, you electrical engineers, ho, hu, ho. I almost laughed! Erfolg Quote Link to comment Share on other sites More sharing options...
Vecchio Austriaco Posted August 5, 2010 Author Share Posted August 5, 2010 Be carefull Carl - wanted to say Erfolg - today there are 1500km between us - next week much less.... By the way - nothing as simple as that. and you don't need to fiddle with the position of the servo having trouble with non linear movement because of different angle and different legth of the push rods.... VA Quote Link to comment Share on other sites More sharing options...
Erfolg Posted August 5, 2010 Share Posted August 5, 2010 So you are joining us! At least it is the south, where the weather has been much drier this year than in the north. Booo Hooo All the best. I have just come back from Sherwood Forest, I told my grand daughter about Robin Hood. Who split an arrow in competition held by the wicked Sheriff of Nottingham. His (Robin Hood) mission in life was to rob the wealthy, because they had more money than the poor. Then I then went on to explain the tale of William Tell (he lived in Switzerland you know). How he fought against the wicked Austrian Lord Gessler, who had invaded Switerland, to set them all free. Today he(Willie) would be called an insurgent terrorist. She asked did he wear a Lincoln Green Tunic! I hope you mentioned re-centring the pot. Carl Erfolg Quote Link to comment Share on other sites More sharing options...
Vecchio Austriaco Posted August 6, 2010 Author Share Posted August 6, 2010 Erfolg, No need to recenter the pot - didn't open the gears and the little remaining error doesn't change the performance of the servo. By the wat - I will not pack a Lincoln green tunic - but carefull as I am I will pack my Barbour border jacket - which suffered a life in the wardrobe during the last 11 years .... Also my experience with bow and arrow is bad - result was a blue arm from ellbow to hand... VA Quote Link to comment Share on other sites More sharing options...
Erfolg Posted August 6, 2010 Share Posted August 6, 2010 Vecchio It is interesting that re-centring was not required. In the dim and distant past when reversing servos was common, the type I used, did exhibit a shift. Although I expect that the pot is a standard feed back arrangement, it could well have been an issue with the electronic electrical components. I guess times change. It always seemed strange to me that Robin (or is it Robbing) Hood (as in head covering) and his band, was not noticed by when in the community by the official law enforcement guys, when dressed in Lincoln Green clothing. I can normally spot a soldier when in his camouflage tunic when in public. Ahhh, yes, there was no National Health service and they needed glasses. I thought William Tell, was an every day guy, not prone to wearing fancy dress? Erfolg Quote Link to comment Share on other sites More sharing options...
Tedder Posted August 9, 2010 Share Posted August 9, 2010 Now we are on the subject of servo's, I am trying to work out the best way to mount and control the Elevator and Rudder of a Kielcraft Junior 60, I built this model when I was in the RAF about 1947. This time it will be electric power I am well on way to finishing it, but I want to rig up the controls before I cover it, any tips. Regards Teddar Quote Link to comment Share on other sites More sharing options...
r6dan Posted February 5, 2011 Share Posted February 5, 2011 If I reverse the polarity of the two wires coming from the motor will it run backwards? Quote Link to comment Share on other sites More sharing options...
John Privett Posted February 5, 2011 Share Posted February 5, 2011 Dan, you'd need to reverse the two wires at each end of the feedback potentiometer as well. If you don't, the servo will simply run and jam against the end-stop at one end or the other depending on the stick position on the tx. Quote Link to comment Share on other sites More sharing options...
r6dan Posted February 5, 2011 Share Posted February 5, 2011 Is that the 3 wires that come out of the bit that isn`t the motor? Quote Link to comment Share on other sites More sharing options...
John Privett Posted February 6, 2011 Share Posted February 6, 2011 The f/back pot will certainly have three leads and has a shaft turned by the servo gears. So if you've found something that isn't the motor, has three leads and is connected to the servo gears then that's got to be it! Quote Link to comment Share on other sites More sharing options...
Adrian Smith 1 Posted February 6, 2011 Share Posted February 6, 2011 To save all this fiddling about why not by a servo reverser for around 11 quid from SMS in Cranfield Bedford. I have aways used them for when two servos required for the elevator with a y-lead. It's never let me down and will take power from 6 volt RX battery for the more powerful servos. Why take kit apart and mess around with leads where perfect soldering is required which in my view increases the margin for things going wrong. Quote Link to comment Share on other sites More sharing options...
Steve W-O Posted February 6, 2011 Share Posted February 6, 2011 Posted by Adrian Smith 1 on 06/02/2011 11:48:34: To save all this fiddling about why not by a servo reverser for around 11 quid from SMS in Cranfield Bedford. I have aways used them for when two servos required for the elevator with a y-lead. It's never let me down and will take power from 6 volt RX battery for the more powerful servos. Why take kit apart and mess around with leads where perfect soldering is required which in my view increases the margin for things going wrong. The first servos I reversed were in the early 70's. I had assembled them from scratch, as I had the transmitter and receiver, so I don't see four wires as much of a risk or challenge. Many modellers have the experience to find it a simple and straightforward task, so why spend the same as 4 small servos and add extra weight? Quote Link to comment Share on other sites More sharing options...
r6dan Posted February 6, 2011 Share Posted February 6, 2011 Posted by Adrian Smith 1 on 06/02/2011 11:48:34: To save all this fiddling about why not by a servo reverser for around 11 quid from SMS in Cranfield Bedford. I have aways used them for when two servos required for the elevator with a y-lead. It's never let me down and will take power from 6 volt RX battery for the more powerful servos. Why take kit apart and mess around with leads where perfect soldering is required which in my view increases the margin for things going wrong. Because I can`t afford to waste money on stuff that with a bit of thought and help from people on here I can do myself. And what Steve said too... Edited By r6dan on 06/02/2011 12:25:20 Quote Link to comment Share on other sites More sharing options...
r6dan Posted February 6, 2011 Share Posted February 6, 2011 I did as instructed, below is what I did It longer for the iron to warm up than to do the job!! Quote Link to comment Share on other sites More sharing options...
Steve W-O Posted February 6, 2011 Share Posted February 6, 2011 Posted by r6dan on 06/02/2011 13:19:31:I did as instructed, below is what I did It longer for the iron to warm up than to do the job!! Well done, the saving of the £11 must add to the feeling of achievement Quote Link to comment Share on other sites More sharing options...
r6dan Posted February 6, 2011 Share Posted February 6, 2011 Yes,that £11 will buy half the servos for the Webbit Quote Link to comment Share on other sites More sharing options...
Erfolg Posted February 6, 2011 Share Posted February 6, 2011 I am very surprised that servo reversing is necessary in this era, With Tx's normally having servo reversal facilities as standard. As with most things there will always be the odd situation. From my days as a 70's modeller when servo reversing was standard, I would baulk at the idea to-day. Although in principal really easy, in practice a rather fiddly operation. Even mote so if a 9g or less servo. I would lash out a £10 these days, if only one is required, as those Chinese ladies all solder to a far higher standard than myself. Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted February 6, 2011 Share Posted February 6, 2011 twin elevators wghere physically a servo cannot be fitted correctly for direction, same with a situation I have right now...My steerable nosewheel servo and rudder servo are coupled via a Y lead, no spare channels to do a mix, but wheel goes one way, rudder goes the other. Need to reverse just one of the servos IYSWIM Quote Link to comment Share on other sites More sharing options...
Hamish Posted February 6, 2011 Share Posted February 6, 2011 Erfolg, I used two servos for flaps each havingt he same orientation and connected to a the gear channel through a Y lead, so altered as above. . Saved a channel. Quote Link to comment Share on other sites More sharing options...
John Privett Posted February 6, 2011 Share Posted February 6, 2011 My first radio set - Futaba M6 - in the 1970s was supplied with a mix of "red label" and "black label" servos. These rotated in opposite directions. Quote Link to comment Share on other sites More sharing options...
r6dan Posted February 6, 2011 Share Posted February 6, 2011 Posted by Tim Mackey - Administrator on 06/02/2011 16:25:54: twin elevators wghere physically a servo cannot be fitted correctly for direction, same with a situation I have right now...My steerable nosewheel servo and rudder servo are coupled via a Y lead, no spare channels to do a mix, but wheel goes one way, rudder goes the other. Need to reverse just one of the servos IYSWIM Its easy peasy! I could have mixed it to, say the gear channel switch but If I caught the switch taking the TX out my bag and didn`t realize it bad things would happen! Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted February 6, 2011 Share Posted February 6, 2011 The trick here is to set gear travel to 0% in both directions then the sw is null. Quote Link to comment Share on other sites More sharing options...
r6dan Posted February 6, 2011 Share Posted February 6, 2011 Ah, I never thought of that!! Quote Link to comment Share on other sites More sharing options...
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