Post by thread:[EE]: Servo Schematic

>Related to the other thread, about driving servos, does >anyone happen to have an actual schematic for the internal >electronics for a 3-pin, RC-model type servo? Here you are http://www.seattlerobotics.org/encoder/200009/S3003C.html ---8<---Corte aqui---8<---- Alexandre Souza spam_OUTtaitoTakeThisOuTterra.com.br http://planeta.terra.com.br/lazer/pinball/ ---8<---Corte aqui---8<---- -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

I probably have one for an old ACE servo. ACE provided complete schematics/theory of operation of all their radio equipment(since many were kits) and you could order every part/component.They used the Signetics NE544 as most all servos of the 70's-80's did. According to https://www.fmadirect.com/home.htm all of todays servos use the same Mitsubishi chip but I don't know if it emulates the old Signetics chip. I also have a book with circuits from 60's-70's > > Related to the other thread, about driving servos, does > anyone happen to have an actual schematic for the internal > electronics for a 3-pin, RC-model type servo? > > thanks, > - dan michaels > http://www.oricomtech.com -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

On Tue, 17 Jul 2001, Mike DeMetz wrote: > I probably have one for an old ACE servo. ACE provided complete > schematics/theory of operation of all their radio equipment(since many were kits) > and you could order every part/component.They used the Signetics NE544 as most > all servos of the 70's-80's did. According to https://www.fmadirect.com/home.htm > all of todays servos use the same Mitsubishi chip but I don't know if it emulates the > old Signetics chip. > I also have a book with circuits from 60's-70's > > > > Related to the other thread, about driving servos, does > > anyone happen to have an actual schematic for the internal > > electronics for a 3-pin, RC-model type servo? Actually I have seen two different chip types in the last few months. One (Airtronics) uses a single IC, the other (Futaba) uses a pair, one servo logic/timing and one H-bridge driver. I found schematics of the 2-chip version on a robotics page -- don't have it with me, but I think it was the PARTS web site (Portland Area Robotics Society, I think), which is a really cool place to visit. Dale -- A train stops at a train station. A bus stops at a bus station. On my desk I have a workstation... -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

On Tue, 17 Jul 2001, Mike DeMetz wrote: > I probably have one for an old ACE servo. ACE provided complete > schematics/theory of operation of all their radio equipment(since many were kits) > and you could order every part/component.They used the Signetics NE544 as most > all servos of the 70's-80's did. According to https://www.fmadirect.com/home.htm > all of todays servos use the same Mitsubishi chip but I don't know if it emulates the > old Signetics chip. > I also have a book with circuits from 60's-70's Almost forgot o mention -- I have some old NE544's if anyone wants to play with them. A very kind Signetics rep sent me a dozen or so back in bout '90, thy've never made it out of the antistatic foam. Dale -- A train stops at a train station. A bus stops at a bus station. On my desk I have a workstation... -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

Alexandre Souza wrote: >>Related to the other thread, about driving servos, does >>anyone happen to have an actual schematic for the internal >>electronics for a 3-pin, RC-model type servo? > > Here you are > > http://www.seattlerobotics.org/encoder/200009/S3003C.html > Alexandre, mucho gratias. That is exactly the same pcb as inside the servo I have. The schematic shows an unknown cap across the motor, plus 2 15K resistors, but these appear to be wired in a speed sensing ckt. The cap must be the noise suppressor here. thanks, - dan michaels http://www.oricomtech.com ========================= -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

Dan: The Signetics data books I have show the NE544 the schematic for its use. There is also application note AN133 that gives more detail on how to use the chip. Very informative. If you can't find the data elsewhere then I can scan it for you. -- Rich Dan Michaels wrote: {Quote hidden}> > Related to the other thread, about driving servos, does > anyone happen to have an actual schematic for the internal > electronics for a 3-pin, RC-model type servo? > > thanks, > - dan michaels > http://www.oricomtech.com > ========================= > > -- > http://www.piclist.com hint: PICList Posts must start with ONE topic: > [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

Rich Ottosen wrote: >Dan: >The Signetics data books I have show the NE544 the schematic for its >use. There is also application note AN133 that gives more detail on how >to use the chip. Very informative. > >If you can't find the data elsewhere then I can scan it for you. > Many thanks to Mike and Dale and Rich for your responses. Alexandre's link provided the schematic for the exact servo I have, Futaba S3003. It uses one BAL6686 h-bridge and one BA6688 servo control chip. I assume the 6686 has clamp diodes built-in, but I'll have to see if I can find the specs. Other than that, it looks like the only built-in noise suppressor is a cap across the motor - value unknown. I guess I don't need an NE544 datasheet, but it would be interesting to know what sort of noise filters might be present in the servos that use that chip. I think Drew might also use some help in designing a good filter for his servo problem on the other thread. thanks, - dan michaels http://www.oricomtech.com ========================= -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

Thanks for you well formulated question Dan that brought the right answer. I have been looking for the H-Bridge of this type of servo for a very long time :)) Trough Alexandre's link I have found that both circuits BAL6686 and BA6688 are available from www.angelfire.com/biz/techsonic/page2.html. The BAL6686 is also available from Futaba for 3.75USD Thank you guys, Gaston. Dan Michaels wrote: {Quote hidden}> > Rich Ottosen wrote: > >Dan: > >The Signetics data books I have show the NE544 the schematic for its > >use. There is also application note AN133 that gives more detail on how > >to use the chip. Very informative. > > > >If you can't find the data elsewhere then I can scan it for you. > > > > Many thanks to Mike and Dale and Rich for your responses. > > Alexandre's link provided the schematic for the exact servo I have, > Futaba S3003. It uses one BAL6686 h-bridge and one BA6688 servo control > chip. I assume the 6686 has clamp diodes built-in, but I'll have to see > if I can find the specs. Other than that, it looks like the only > built-in noise suppressor is a cap across the motor - value unknown. > > I guess I don't need an NE544 datasheet, but it would be interesting > to know what sort of noise filters might be present in the servos > that use that chip. > > I think Drew might also use some help in designing a good filter for > his servo problem on the other thread. > > thanks, > - dan michaels > http://www.oricomtech.com > ========================= > > -- > http://www.piclist.com hint: The list server can filter out subtopics > (like ads or off topics) for you. See http://www.piclist.com/#topics -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

Does everybody receive my message in two copies ? If so, can someone tell me why is this. I am using Netscape Communicator 4.73 Regards, Gaston. Gaston Gagnon wrote: {Quote hidden}> > Thanks for you well formulated question Dan that brought the right answer. > I have been looking for the H-Bridge of this type of servo for a very long time :)) > > Trough Alexandre's link I have found that both circuits BAL6686 and BA6688 are available from > www.angelfire.com/biz/techsonic/page2.html. > The BAL6686 is also available from Futaba for 3.75USD > > Thank you guys, > Gaston. > > Dan Michaels wrote: > > > > Rich Ottosen wrote: > > >Dan: > > >The Signetics data books I have show the NE544 the schematic for its > > >use. There is also application note AN133 that gives more detail on how > > >to use the chip. Very informative. > > > > > >If you can't find the data elsewhere then I can scan it for you. > > > > > > > Many thanks to Mike and Dale and Rich for your responses. > > > > Alexandre's link provided the schematic for the exact servo I have, > > Futaba S3003. It uses one BAL6686 h-bridge and one BA6688 servo control > > chip. I assume the 6686 has clamp diodes built-in, but I'll have to see > > if I can find the specs. Other than that, it looks like the only > > built-in noise suppressor is a cap across the motor - value unknown. > > > > I guess I don't need an NE544 datasheet, but it would be interesting > > to know what sort of noise filters might be present in the servos > > that use that chip. > > > > I think Drew might also use some help in designing a good filter for > > his servo problem on the other thread. > > > > thanks, > > - dan michaels > > http://www.oricomtech.com > > ========================= > > > > -- > > http://www.piclist.com hint: The list server can filter out subtopics > > (like ads or off topics) for you. See http://www.piclist.com/#topics > > -- > http://www.piclist.com hint: The list server can filter out subtopics > (like ads or off topics) for you. See http://www.piclist.com/#topics -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

> >Gaston Gagnon wrote: >> >> Thanks for you well formulated question Dan that brought the right answer. >> I have been looking for the H-Bridge of this type of servo for a very long time :)) >> >> Trough Alexandre's link I have found that both circuits BAL6686 and BA6688 are available from >> www.angelfire.com/biz/techsonic/page2.html. >> The BAL6686 is also available from Futaba for 3.75USD >> >> Thank you guys, >> Gaston. >> Gaston, I could not get that link to work, nor the search engine at Rohm. I am sure these Rohm parts, but could not find the parts mucking around the website: http://www.rohm.com/products/shortform/11motor/motor1.html thanks, - dan michaels http://www.oricomtech.com ========================= -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

Dan if you are referring to this link, www.angelfire.com/biz/techsonic/page2.html and you are using Netscape communicator, there seems to be nothing after "Here is our partial listing for Semiconductors: Please click here to order on-line" but if you persist and go way down the page, after many blank lines, you will see the list of parts with unit price and quantity 1-10. Opera browser shows the list where you would expect it. Gaston. Dan Michaels wrote: {Quote hidden}> > > > >Gaston Gagnon wrote: > >> > >> Thanks for you well formulated question Dan that brought the right answer. > >> I have been looking for the H-Bridge of this type of servo for a very > long time :)) > >> > >> Trough Alexandre's link I have found that both circuits BAL6686 and > BA6688 are available from > >> www.angelfire.com/biz/techsonic/page2.html. > >> The BAL6686 is also available from Futaba for 3.75USD > >> > >> Thank you guys, > >> Gaston. > >> > > Gaston, I could not get that link to work, nor the search engine at > Rohm. I am sure these Rohm parts, but could not find the parts mucking > around the website: > > http://www.rohm.com/products/shortform/11motor/motor1.html > > thanks, > - dan michaels > http://www.oricomtech.com > ========================= > > -- > http://www.piclist.com hint: The list server can filter out subtopics > (like ads or off topics) for you. See http://www.piclist.com/#topics -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

I have a schematic I can't send over, but I'll tell you it won't help you. It uses a custom-ordered servo chip and a few passives. The chip is DIP8 with no heatsink. You may have better luck hunting for datasheets of said chips (they come with application schematics). National had the 'original' integrated drivers, at least 15 years ago. Try an old National special purpose catalog. They do describe the internals a little afair. There is nothing they can do that a 12C508A can't do, except the power driver. Normal servo chips have H bridges that can run 1A at 4V supply with little losses (<1W). Peter -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.