bikz

Hi there....first and foremost Happy New Year......

Ok back to my question.....i have been using standard Sanwa Srm 102 servos with my futaba receiver with no problems....ok i also have this same servo which was previously connected to a 27Mhz Am(SANWA RECEIVER) receiver....

the wires on the servos have different colours compared to ones i use on the PCM transmitter......which is black-black-red(AM receiver used servo).........while the ones on the PCM receiver is blue-red-black.....ok the problem is that once i put the servo from the AM receiver to the PCM receiver it does not work.....

is it because some polarity is off and can i do something to make it work on my PCM receiver...thanks

JohnBuckner

My Feedback: (1)

I can,t say about the rest of the world but in North America Airtronics changed the polarity of their plugs around five or six years ago to conform with the three other majors. The current Airtronics 'Z' plug has a center pin positive as the other majors now all have. Prior to this Airtronics plugs was positive on the #3 pin. In other words the positive and negative leads on the old and new plugs have been reversed.

If you have managed to plug and old style plug into a receiver with new style (Z) ports or vice versa then it is probable that damage has been done to the Rx and/or the servo.

John

QUEERBOX

Hi--- and happy new year to you too!!



Bit of a coincidence this one-as i am having a similar problem.
I am using srm-102 servos, with an infinity 660 Tx and srd-6102rs PCM Rx
They work perfectly, but i cannot get my futaba sd200 servos to work at all
I have swapped the wires to the advised positions,but had no luck.
In complete frustration i have tried all combinations of wiring positions-and
switched from PCM to PPM in each positon to no avail.


this leads me to think that thier is another compatability problem!
possibly something to do with the pulses this reciever sends to the servo?
Its realy bugging me now, but at least i know i am not the
only one who has found this problem

does anyone know if i can use a different reciever with this transmitter
that will operate my futaba servos correctly?

Anyway if its any help-my srm-102 servos work fine with my PCM reciever, with the bumpy bits on the plug facing me they are wired red-bottom black-middle blue-top
hope this is of use ----and if anyone can awnser my questions it would be greatly appreciated CHEERS

JohnBuckner

My Feedback: (1)

If you have reversed the positive and negative leads of a servo with a centerpin positive plug and installed it in a Rx intended for a servo with a centerpin positive - or - If you have reversed the positive and negative leads of a servo with a #3 pin positve and installed it in a Rx intended for a servo with a #3 pin posittive -- its very likely you have damaged either the Rx or the servo likely both.


Buy the way Box those 'bumpy bits' (three splines) on the plug indicate it is an old style Airtonics plug intended to be #3 pin positive only. If the Rx port you are pluging it into does not have slots for those three bumpy bits then that Rx is to be used with servos using only a center pin positve plug.


John

QUEERBOX

Hi John
Thanks for your reply-you do appear very knowlegable on these matters-as i have read many of your
other posts.



Unfortunately i am still a little confused, i have not had a great deal of experience with
the electronics side of my models- so please bear with me if i appear a bit thick.


After reading your reply i checked my servos by plugging them into a futaba reciever
that i know is ok - and used the futaba transmitter. Servos are ok (phew)


I then plugged my sanwa servos into my sanwa reciever-used the sanwa transmitter
-reciever operates servos fine-so not knackered the reciever (phew!!!)



As i said -i have tried swapping the wiring positions-but still cannot get the futaba servos
to operate with the sanwa reciever-which is the type that accepts the servos with the "bumpy"
plugs-which my sanwa servos have!


Do you know of another issue with these old type recievers that could be
causing my problems?
If i were to purchase another sanwa reciever (a new model) would it still
work correctly with my transmitter- as this would be the simplest solution
and i can then use my existing reciever with the sanwa servos in a different model
thanks for your help

bikz

hei guys ...mine is the older servo for sure....the thing is i want to try and change the 3rd +ve pin into the middle one....
i opened it up and its look pretty complicated and everything is so closeby....so any tips on how it can be done..thanks/

QUEERBOX

HI, if you mean you intend to alter the wiring inside the reciever-DONT!!!
It is much easier -and safer to swap the wiring at the plug on your servo.
dont forget you have done this though-because i have damaged a couple of servos-since my
last post-due to swapping stuff about and forgeting to alter the wiring back again-
small servos seem to be the most prone to damage if you accidentaly get the polarity wrong .
larger servos seem to cope with reverse polarity for a very short while-about the time it takes
to go AAAAARGH and yank the plug out again.
be positive that you have the polarity correct on your reciever-cause they dont like it at all!!
A little puff of smoke and a funny smell indicates you have got it wrong-and you can chuck it away after that-not much chance of repair because it is impossible to get a schematic wiring diagram-from any manufacturer-and by this time you have obscured any component markings tht you could have read to get a replacement part!


unfortunately the damage done to servos cannot even be seen-mine look perfect inside
just dont work


all this info was found out by "destructive testing"done on behalf of all RCU
members-so any contributions towards replacement equipment woul be appreciated
Failing that if anybody knows how to repair servos and recievers-and does it on the cheap
CONTACT ME

The PIPE

Dear Bikz:

The PIPE from New England USA here once more...

and at http://www.vision.net.au/~timotsc/servlead.gif , AND at http://www.fatlion.com/sailplanes/servos.html , are a couple of SERVO hookup diagrams that SHOULD help you get things straightened out on Sanwa/Airtronics servo hookups!

In North America, the Sanwa line of radio control gear IS usually sold under the AIRTRONICS name brand. I've got some "older" Airtronics servos from the early and mid-1980s that I've been using for throttle purposes these days, and those "earlier" Airtronics servos had an ALL BLACK "ribbon" style cable going from the servo out to the connector, as they came from the factory in Asia, with a RED stripe designating the plus, or +5 volt, positive power wire. The second link I've given here shows this for the older Airtronics servo plug.

It is VERY important to note that only OLDER Airtrnoics servos used this "proprietary" hookup...in recent times Sanwa/Airtronics servos NOW use so-called "Z" connectors, which have the EXACT same servo hookup as Futaba and JR made servos..with the red plus power wire in the CENTER position, instead of on one end! It seems you MAY have "sizzled" a Sanwa servo or two of yours, because you didn't know about that changeover.

Just hoping you CAN get any gear you have easily repaired, that could have been damaged from that switch of the Sanwa/Airtronics red marked "plus" wire from one end to a center position...hope this helped..!

Yours Sincerely,

The PIPE!

bikz

BOX...i feel for ur executed servos!...hope that doesn't happen to me....and u're right i was intending to change the wires at the servo cause if I fry the receiver...the cost is too much!!!!!!
i hope someone helps u repair em soon....and on behalf of RCU...our thanks for frying em during testing out on how to get their polarities right!
Pipe.....those diagrams helped me alot..thanks.....now to go see if i get the serovo to work without any "puffs" or smokes!!!

hebertjj

Bikz,

Just swap the wires at the servo plug end. You can pull the wire and metal end out of the plastic housing by either lifting the plastic finger of the housing with the tip of an Xacto blade, or pushing down a metal barb of the metal end with a straight pin. You also may have to shave down some of the plastic ears on the connector housing. Just remember the red line goes in the middle for the PCM and other late systems.

4*60

My Feedback: (41)

This shows the old Sanwa Airtronics vs the others. The Airtronics blue/Z is the same as the others.

http://www.fatlion.com/sailplanes/servos.html

bikz

well guys it worked perfectly and thanks to all of you for all the tips....cheers.
i just did that...pulled out the + and - plugs and swapped em at the plug end.....trimmed the plug and thats it....THANKS.

Javier Garcia

There is another older Sanwa/Airtronics servo, whose wide conector (white in colour) is the double, and the three cables are black. But one of them, on one side has a white/grey strip, which is the + volt.
Be carefull marking or rounding a label on the cable, specifiing the type they are. As a user of both receivers types, I advise you beccause you´ll forgot (like I did) when changing servos from one plane to another, and you will see "smoke" again.