4 Known Bad Victor 888s

Technical Electrical
#1

Our team just wired up our prototype bot and much to our surprise, we have 4 bad Victor 888s right out of the box. We are positive that our wiring is correct- it was done by a 4th year member and double checked time and time again. We have 6 more we got with our shipment and are going to test them tonight to see if they are good.

We plan on returning them and/or getting new ones, but have any other teams had an issue like this where multiple motors just seem to go bad?

These are directly out of the box. We bought them before build season started from VEX Pro.

#2

What behavior are you seeing from the “bad” victors? could it be a calibration issue?

#3

When we try to calibrate the bad ones, they just continue blinking yellow. They don’t flash red/green/yellow like the good ones do. At first we thought it might’ve been our CIM motor somehow blowing it up, but we swapped a Victor out with another and it worked fine.

We are using AM Super Shifters, and pushed the robot maybe a maximum of 8-12 inches on the ground on low gear last night when we tried to get it driving. Could this have blown the speed controllers?

edit: Swapped a bad one out with another, and we have liftoff. Sure would be nice to know how it broke. The manual says the problem is “internal damage”- which could be anything.

#4

If it just continues blinking yellow that points to a faulty PWM connection usually, check your connection and make sure the pwm cable pins are nice and lined up before inserting the cable.

Bad victors are usually very easy to diagnose due to smoke coming out of them, I’ve only had this happen when I was dumb and let some large metal swarf land in them.

#5

We thought we were having wiring problems on our 888s as well, until we realized that we had to push the PWMs in a little bit further than usual. Otherwise the CRIO’s signal doesn’t reach the Victors and they continue to blink yellow.

#6

We also have swapped a PWM cable from a working Victor in to one of the faulty ones and it still continued to blink, so we don’t believe this is our issue. It’s not smoking either. We really don’t want to return these if we don’t have to!

#7

We tested on of ours, worked out of the box. If they are just blinking it is usually because of a loose cable.

#8

Leave the cable plugged into the Victor, and unplug the other end from the DSC. Hook the signal and ground pins of the unplugged end to a cheap handheld digital multimeter that has a diode tester (e.g. Velleman DVM850BL). Post your results here.

#9

If you’re still having trouble after troubleshooting on your own make sure to give us a call at 903-453-0802 or emal support@vexrobotics.com and we can help you figure out what is going on and/or replace the Victors if necessary.

Best,
Ricky

#10

Compare a working Victor to a bad Victor. Is the PWM cable inserted to the same depth on both?

#11

The PWM cables are pretty hard to settle in there, but they are hooked in. [Scratch this] We now believe it might be a defunct PD board. But essentially what is happening when we enable is:

  • 2 Victors are solid yellow.
  • 4 Victors continue to blink.
  • The 4 blinking are wired to our CIM motor, and will not output any power.
  • If we swap out one of the blinking Victors with a solid-light Victor, the motor gets power, as expected.

Certain slots could be busted on our PD board, we’re still troubleshooting. (also, on hold with VEX Pro. Thanks Ricky!)

edit: disregard, our PD board is fine.

#12

I have to ask the silly questions:

  • Are the 3 Digital Sidecar power LEDs all brightly lit green?
  • Do you have a second DSC you could try the PWM cables in (& 12v power & 37-pin cable)?
    *]Code opening all PWMs?
#13

[/li]
Am I reading that correctly? Do you have 4 speed controllers wired to a single motor?

#14

You read my mind.

#15

No, we’re using 2 AM Super Shifters. Each has 2 motors, each separately wired to it’s own speed controller.

#16

Robby,
If the Victor has an illuminated LED then the PD is working. Everything sounds like the PWM cable is not full inserted. These can be tricky as it is possible for the pins to miss the female connector inside the block. Once fully inserted, less than 1/8 inch of the PWM block is visible above the shoulder of the Victor housing. It is possible to fully insert the connector and still miss the female connector.

#17

We have never had issues with Victors until this year. We have one that may or may not be broken (turned on the robot one day and only one side of the drivetrain moved). We’ve yet to fully look into it, but at first glance it does appear to be broken. It was one from last year though, not right out of the box

#18

The fan is not working on one of our 888s.

#19

Taylor,
Nine times out of ten, the fan wire was crimped before the wire was stripped.

#20

I’d check the following:

  1. Whether PWM connector is properly inserted into the Victor. It is easy to misalign. It often appears to be plugged in properly, but the pins don’t actually go into the connector inside the Victor housing, but slide off the side instead. Remove the PWM connector and see if the pins are bent all to one side slightly. If so, the connector was plugged in incorrectly. Straighten the pins, and try again. Wiggle the connector slightly as you insert it. The connector should take very little force to fully seat. If you have to push hard, you’ve missed the connector.

  2. Check the ribbon cable from the Digital Sidecar to the cRIO module. If some of the wires were not fully crimped in the connector, some of your DSC pins won’t work. This is likely the case if some of your PWM ports don’t seem to be working. You can verify this quickly by connecting one of your blinking Victors to a PWM port that was successfully driving a non-blinking Victor.