RS V1: Bad motor controller chip?

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Narbat
Narbat's picture
RS V1: Bad motor controller chip?

I have an RS V1 which I'm pretty sure has a bad motor controller chip, though I'd love someone to tell me otherwise.

Symptoms: On powerup the eyes light and it makes the appropriate grunting noises, but there's no movement. Likewise when receiving commands from the controller, the eyes and sounds are fine but no movement. The touch sensors all work and the hand LEDs light normally.

Opening the chest I see no loose connections, bad solder joints, or anything else visibly wrong. I've got the RS hooked up to a bench power supply at 6V, and see that he's momentarily pulling more than 1A on powerup. When idle he's pulling about 0.6A.  That's way more than I'd expect. The motor controller chip (U3) is scorching hot to the touch. I've individually disconnected all the motors and the symptoms persist, so I don't think there's a short somewhere.

So, like I said, I'm pretty sure it's the controller chip. But I'd really like someone to tell me, "Oh, that happens when a transistor is blown. Replace transistor XXXX and you're golden."

Mainboard rev 6008-10C, if it makes any difference.

GWJax
GWJax's picture

That does not sound too good my friend, Does your chip have a heat sink on it like mine does? if not then it's most likely burnt up from over ramping one of the motors. If I have a chance I'll look into further for you as one of my V1's is already ripped down for mods.

Jax

ps. can you post a picture of your board, front and back for us..

PaulCarew
PaulCarew's picture

I know that you originally posted this 5 yrs ago, but I now have a RSV1 with the same problem (at least, the same as in no motion).

 

Did you ever get a resolution?

Cheers

 

Narbat
Narbat's picture

Dang, has it been that long? I've *got* to clean off my workbench. The little guy is still there, pushed way to the back and buried under other unfinished projects. No, sorry. I figure the controller chip needs replacing, and as I recall it's a surface-mount chip. Beyond my skills and tools.

PaulCarew
PaulCarew's picture

Well, here we are 2 years further on....and I've finally tracked down a replacement motor driver chip and have fixed the RSV1..If you're still wanting to fix that dusty RSV1, I have a spare MD3770G motor chip that you're welcome to (you should verify that that is the correct chip number, I believe a couple of different chip types were used)https://www.dropbox.com/s/elz9eundobrajsr/2015-09-29%2023.53.53.mp4?dl=0Paul.