Negative pulse servos.
Ok...
I called Radio South, and spoke to them on the Royal Mini-Titan Servos. During the conversation, they mentioned that they are probably negative pulse, and probably will not run with anything on the market today. Seems that some of the older radios (Pro Line and really old Airtronics) had a negative pulse on the servos signal wire to drive the servo in the proper direction. I did notice that the servo would drive (looking from the top) completely to the left, and then just sit there, buzzing. I removed the case top and the gears, and turned the pot by hand, and the buzzing all but stopped, but trying to re-center the pot made it run very fast.
Radio South mentioned that the signal wire could be disconnected at the amplifier board, and one of the transistors by-passed, to convert the servos to positive pulse. The trouble is, there are no schematics to be found on the Royal brand servos. It seems simple enough, I would just have to figure out which transistor to bypass. The trouble is, the signal wire is attached to a point on the board, that is shared with TWO transistors, which look identical. One of the three legs on each transistor is on the same board land as the signal wire.
Are there any tekkies out there that can help out with this? Is there some way to follow the lands from each transistor leg to some other component/wire, to isolate which transistor it is that I need to bypass? Any help would be appreciated!
Failing this, is there anyone interested in some brand new (though older equipment) mini-servos that have 33 in/ounce torque at .16 sec speed?
Thanks in advance for any help offered with this.