servo control IC

[Simon]

I have been given an RC servo to solder whires back on. Looking inside it has just one IC, 2 transistors and a few passives and the output shaft looks like it is actually a pot that is feeding back position info (nothing new here), we have similar things at work in the form of water valves that drive a pot for position feedback but there is no driver. I have always assumed a mcu thing would be required to control it but if a single IC solution can do it all the better. But now the IC is marked 2607D made by acoms, I can't find much about this IC. Any ideas ? or are there standard IC's out there that will control a servo system.

I assume the input is PWM or a varying voltage (that could be low passed PWM)

[Kibi]

Yes, they do work on a PWM signal down the yellow or white, sometimes blue wire. It's a 50Hz signal with a pulse width of between 1.0 and 2.0 ms, 1.5ms being the centre of the servo's travel.
Acoms are a well known brand of servo, mainly the lower end of the market. It would seem that they are getting their own chips fab'ed.
I never really bothered taking servo's apart in my RC days, if it was knackered then it was due to mechanical stress. Off road RC racing really hammers even the metal geared high speed, high torque servo's.
If it was a really expensive servo and the output MOSFET's had allowed their smoke to come out then it would be worth mending it, but this was rare.

[free_electron]

look up the NE576 i believe. that is a traditional servo controller chippie. used in lots of servos from Graupner and others

[notsob]

here's another RC chip - just for you info

[Simon]

right thanks, My technical director asked me to fix it for him. Bottom of the market, yes, the wires were soldered to the IC legs on the component side and had come off so he asked me to solder them back on. When I saw hot it worked I immediately recognized it as the same sort of "tracker" system we need for some motorized fluid valves.

[Psi]

You can get new servos for $2 from hobby king but they're obviously not that well made
I recommend getting $4+ ones, they work fine.

[Simon]

Well I'm not looking for an actual servo, I have the mechanical side of it already, but I need the circuitry to control it. I either write software to do it or use a cheap dedicated chip.

[RCMR]

Buy a budget servo from HobbyKing that is about the same size and transplant the servo-amp board to the servo you're fixing

Here's what I mean:

http://rcmodelreviews.com/make_digital_servo.shtml

[Simon]

I have no interest in fixing the servo, if it don't work he will go buy another one. But I'm interested in the type of IC it uses so that I can use it elsewhere.

[RobB]

another chip was used here
1http://secure.oatleyelectronics.com//product_info.php?cPath=100_112&products_id=841