Carriage Will Not move (as if welded to home position)

[artbot]

i haven't turned my H700 on for several weeks.

upon hitting the on button i hear the vacuums crank up, then a *BONK* noise. i notice that the carriage is not moving back and forth for cleaning.

i turn the printer off, unplug it, even unplug the carriage motor. the carriage is locked in home position. it will not budge left or right at all. it's like it's bolted there.
there is the minimal play up and down. but no side to side.

the back side of the belt is quite tight, the front side has more play.

WHAT THE HELL!???

i'm stumped.

 

[DerbyCitySignGuy]

Can't even manually move it?

It sounds like the drive motor might be seized or something.

 

[artbot]

i believe the servo motors for these have a magnetic brake in them. i'm assuming the brake is stuck "on".

the carriage will not move at all. with great force you can't see it move a micron.

the "bonk" noise (turned it on once more to see if it reset/cured itself) is the sound of the belt. as if you plucked a giant rubber band.

i guess the next thing to do is to unhook the belt from one side of the carriage (pretty huge job, i'd guess) to see if the motor will turn on it's own. it seems that there is a small amount of play in the pulley. that doesn't make sense because there's no play at all at the carriage.

 

[SightLine]

I'd try unplugging the motor before I tried removing the belt. Then you could check for voltage to the motor with a meter..... not sure if its an electric brake but many servo type motors also have some internal gearing in the nose as well that can prevent them from being moved by hand.

 

[artbot]

update:

when i put a phillips head on the gear of the servo, i can get the motor to give me about an 1/8" of play forward and back. the carriage will move with this movement. but nothing past that tiny forward and back.

i'm going to unplug the motor and see if i can get the motor to reset (no brake?). i think i have spare motor in my parts cabinet... might be doing a major repair today.

 

[artbot]

motor is off. still won't move. took tension off the belt, still no move.

with the side off, put my back into it and suddenly it's moving.....???!!!???!!! argh... i took this thing half apart for this?

probably have a bearing going out and it was rolling over onto a flat spot. these bearings have this odd lube port that runs through them. i'm going to clean the rail, and slides like crazy and hope this is a one time thing.

 

[SightLine]

ouch! sort of like a gear with one missing tooth and it happens to stop right there.... any other time it will work fine and skip on past the tooth.

At least its going.