ok i soldered the wires back on. When i hook it all up to the robot it still behaves all crazy. its twicthy and unresponsive half the time. I think i have a defective chip, has this happened to anyone else? I also tried to play with all 6 settings, no positive results…
Perhaps if you were to post some more information about your project we could help you narrow down the possible problems. Are you using a good reliable source for power. Power is a good place to start looking for troubles.
I am using a nexxtech 6.0 V 1500Ah NI-MH batery pack. I am runnning two cordless drill motors rated at 3.6 volts. my transmiter is a futuba attack sr and the reciever is a futuba fp-r122je am 2 channel reciever. i turn on the transmitter first. then the reciever, and then turn on the power to the sabertooth. it is usaully calm after this, but when i start to drive it. it goes nuts. I tested the transmiter and reciever with a couple servos, they work fine. I have no idea what i could possibly be missing.
I am using a Sabertooth 2x5 in my WALTER robot and have not seen this kind of behavior. Which control mode of the Sabertooth are you using, or are you using the R/C version? I have the other one, and am currently using standard R/C PWM from an SSC-32 to control it.
8-Dale
What exact motors are you using and what are their exact specifications? The more specific the information you give us, the better we can help you. You can not provide too much detail… 
8-Dale
the motors say leshi motor, 3805-33008, 3.6 v, 070627/8. that is all i know, they came out of a mastercraft lithium ion cordless screwdriver.
This is the screwdriver.:
Link
Thats all i know, is there anything specific i could figure our for you?
Okay, lets see if we can’t chase this problem down:
First, so we’re all on the same page, which model sabertooth is this? Its clearly one of the R/Cs, but it could be a 2x5 or a 2x10. I’m going to assume that its a 2x10 for the purposes of troubleshooting.
First test: Look at the Status 1 led. When it powers up without an R/C signal, it should glow dimly. When you turn the transmitter on, it should glow more brightly. This is an indicator of having a radio link.
Second thing to look at: If the motors are drawing the battery down below about 5v, the controller will reset, and then autocalibrate to whereever the transmitter is currently, which would definitely cause “going nuts”. Turn auto-calibrate off (switch 5) and see if control improves somewhat. Cordless drill motors with a nominally 6v battery could easily be drawing the battery down below the minimum input voltage if the battery is old, or not fully charged.
If this doesn’t help, do you have reasonable control with small control inputs and then lose control with larger inputs? Again, this would probably be power related.
Measure the battery voltage under load and report back. Anything below 5.5v on a multmeter could be cause for concern.
If none of these help, it may be radio interference (being an AM system) try moving the radio reciever and antenna as far as possible from any motor or battery wiring.
My money is on “battery can’t supply enough voltage at the current levels requested, which browns out the controlle,r which causes it to auto-calibrate to a stick position other than neutral, which causes ‘crazy’”
its a 2x5
Okay, same procedure except there’s not a “status 1” led, there’s just the blue status led.
Based on your other thread, I’m now 100% certain the problem is battery voltage depression under load. When you ask a battery to provide some current, it will decrease the voltage it supplies somewhat. How much is a function of the chemistry, condition and state of charge of the battery. Do you have any 7.2v or 9.6v battery packs you could test with?
Simple voltage checks with a multimeter should determine if voltage is dropping too low during operation.
i will recharge and or try another battery, however it still went crazy with the auto calibrate set to off. when i get home ill check everything out with a multireader.
Can you elaborate on “crazy”
Also, do you have control until it goes crazy, or does it start out crazy?
i have some control, then it goes crazy. seems like the autocalibrate going nuts. it jolts side to side the runs forward or reverse, very random like its trying to calibrate.
do you have decoupling capacitors on the motor terminals?
He’s using a 2 x 5 RC with electric drill motors… 
I went to motors website but the part numbers are no good.
Unless this is like a tiny little toy screw driver it must be drawing a ton of current. You know what the current does with a motor when you try to apply double the voltage? The current, which is already too much for the 2 x 5 is going to be way off the chart. 
You need a 2 x 10 or even a 2 x 25.
It really is a small screwdriver, the motors run fine under the 6v battery. I guess they could still be sucking a lot or current but i wouldnt think so.
i do not have time to get the larger capacity sabertooths.
I tried the system with a fully charged 6v pack, and it worked fine. but after a fe minutes, it went back to going bezerk.
So, would this mean that my sabertooth is ok and that i need a new battery? maybee 2 in parrallel to last a little longer?
This seals it. You need to use a 7.2vdc battery and your problem will go away. Also you do need to make sure you have the decoupling caps on the motors. They prevent electrical noise from the motor from being propagated down the motors wires and possibly interfearing with nearby electronics. But if it’s working well on a fully charged battery going up to the next larger pack should take care of it.
you mean a capacitor between the motor terminals? i always wondered what those where for. what size capacitor should i solder on?
Also, isnt my problem current delivery and not voltage?
and lastly, recharge time needs to be kept as short as possible so should i go with nicad batteries instead of nimh’s, weight is also not an issue as my bot is underweight and could benifit from the weight traction wise at any rate.
Thanks,
Here is a link to an old thread discussing the placement of EMI filter capacitors on DC motors. It should give you enough info to work from.
lynxmotion.net/phpbb/viewtopic.php?t=2148
One affects the other. When you draw a lot of current the voltage will drop. The regulator requires around 5.5vdc coming in to provide a solid 5vdc out to the motor controllers circuitry. using a 7.2vdc battery will provide a buffer preventing the regulator from browning out.
NiCad can probably be charged faster than NiMH so it’s your choice.