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View Full Version : need help choosing new servo for stock ep



betty.k
12-07-2005, 05:18 AM
hiya gang, some of you know me from other sites. ;)

i recently bought a halfeight for a beginner (38yo but new to rc). after following bithed's advice i got him a rtr with oil shocks (sato, really nice product), alloy front tower (gpm), bb's, xspeed motor. i told him to run it with the stock motor for as long as possible while he learns to control it.

he didn't listen! (i probably wouldn't have either!)

so now we gotta get him a servo. after reading the reviews here it seems the hitec 81mg is a good product but i'm stumped with the wiring stats.
i'm guessing the stock rx/esc also has the servo controls on it because of the 4 wire setup. i'm also guessing that i gotta remove the hitec's internal pcb and wire the old plug directly to the motor and pot. is all that correct?

and if so, do the pots from the 2 different servos match value wise?

any help will be great, as i don't have the car in front of me it's a little risky buying the wrong thing. i could always get another stock servo but it seemed a little slow to me (weak too!)

BitHed
12-07-2005, 05:52 AM
...Betty that is definatley ONE way of doing it...Sounds complicated but i know you too well...99% of us just changed out the whole lot...

...You can use the 81 or 85MG Hitec servos...The 81 is slighlty stronger and faster...I used the 85 with ZERo issues...If you have dollars to throw at it i recommend FUTABA HRS, fulll digital...

...You can use ANY RX and ESC...i recommend brushless for the weight savings alone...just make sure that the electronics you DO use will fit under the body...

...If you DO go the route that you mention in your post keep us iformed...Sounds like a monster project but if ANYONE can do it YOU can...You would be the first :cool:

betty.k
12-07-2005, 07:04 AM
see, if this was mine i wouldn't hesitate to hack the hitec or replace the electrics.
but this guy is just keeping it mostly stock as a basher so an electrics swap is out of the budget.
i'd only do the conversion if i knew the servo pot values matched. anyone wanna take a peek for me? :o

QuickEight
12-07-2005, 08:59 AM
I have a couple of the OEM servos. Give me $2.50 for one or $5 for both, plus the shipping, and I will send one or both of them to you.

betty.k
12-09-2005, 03:12 AM
hey quickeight, i'll take those servos if you're still offering.
i don't think i have pm's enabled here so shoot me a mail at: bettykay@gmail.com

thanks! ;)

betty.k
12-16-2005, 04:04 AM
sorry to double post, i'll try to make it worth it! :D

just got my servos from quickeight (THE fastest u.s. - australia shipment to date!) so i popped one open and did some fiddling.

the wiring is as follows:
orange= motor -
white= motor +
red= pot
black= pot (i don't think you need to observe polarity with the pot wires)

i wasn't able to completely remove the pot so i just measured the resistance while it was in the housing. it measured 4.84k ohm which leads me to believe it's a 5k ohm pot. (GREAT news for miniz/iwaver/xmod modders!)

so, if a fancy aftermarket servo also has a 5k pot then wiring it to the stock ep would be fairly straightforward. but most of the time the pots are soldered to the servo esc so there would be a little desoldering and tinkering involved.

CrustyNoodle
03-28-2006, 01:40 AM
Betty,

Did you ever do the conversion modification on the after market servo? I'd love to know if it worked...

CN

CrustyNoodle
04-03-2006, 01:32 AM
Betty,

Some info for you....

http://www.halfeight.com/forums/showthread.php?t=1831

By the way, where is the Paris end of Aus?