Like you, I am now leaning toward a bad stepper or a bad driver chip... but when i ran into that threadlock i decided to stop wasting time on this and see what a modern printer can do....

I have been looking at this since christmas so i ordered it.  monoprice maker ultimate https://www.amazon.com/gp/product/B01JB5GV0W/

It promises .02mm layers.  Since .1mm was mostly a pipedream on my SD until VERY recently. I am curious but pessimistic there is much truth in it.  If i can get the 3dpburner parts printed this weekend without having to do massive recalibration ill probably keep it (pretty good stress test including 2-3inch bridges, 60d overhangs, and such)   If it turns out to require too much babysitting, i may just have to find a new hobby....

I may try resurrecting the sd at a later date if i get bored enough or find a need to sell it.

just out of curiosity - did either of you bother to check into voltage levels of the Y axis stepper drivers?

I have 2 SD4s - same basic machine, just larger and both had voltage issues in stock form

I personally tried everything just short of reflashing the firmware (which in retrospect, I probably should have tried).  While I never did figure out the issue, my best guess is that the Y-Axis stepper motor itself failed, likely slipping under torque pressure every now and then.

I have 2 SD4s - same basic machine, just larger and both had voltage issues in stock form

Edit:. I now hate solidoodle.  I went and disassembled my y axis and re greased everything.  Still have y shifts.  Went to take out the front pullys to see if there was hidden damage and noticed they were attached with red threadlocker.  Unfortunately this was after I stripped the head.  Looks like I have to destroy the brackets.to get it off.  Why use threadlocker on such a delicate part... I know from experience that threadlocker turns abs into dust.  I can't even print rep!acement brackets. 

So.. now my choice seems to be give up and buy another printer or buy some more brackets from someone and break out the blowtorch with no guarantee it will fix anything. 

So much for my laser engraver project...

I feel for you. It had been so long from my original post that I stopped tracking this thread. I would have warned you about A) stripping that head, and B) not being able to do anything after.  I ended up dremeling mine completely off and literally cut a piece of wood as a temporary bracket substitute, using off the shelf nut/bolt to hold it together.

Long story short, I never did figure out what was causing that weird pop/grind/hum noise that was affecting the Y axis. I would be watching prints and hear the pop that would shift the Y axis, but nothing was visibly wrong. Keep in mind, this was after at least a dozen complete disassemble/testing/reassembles, replacing all bearings and pulley bands with factory OEM parts (which took months to get from the practically nonexistent Solidoodle customer service), regreasing with lithium grease, and calibrating for hours on end. It got to the point that I feel that I could have built a 3D printer from scratch faster than trouble shoot this one.

I gave up on it. Shame too, as when it was working, it was producing quality parts for a good 2 years. Ended up splurging on a delta printer. Haven't looked back since.

When i disable the motor, i can move it back and forth without any problems.  after jogging it back and forth using manual controls a few times, it seems to work.  (mostly? I was getting some x/y skew in one print i was assuming was because of overextrusion snags.. maybe it was this)    I was hoping the motor was dying ..or maybe the driver.  Something i could drop in and forget about for a little while.

All my brackets seem fine.  the belts have same tension they always have.

I finally got confident enough with my calibration etc to attempt a real project (3dpburner) and this shows up ..sigh.  Anything you guys can suggest before i buckle down and rebuild my Y-axis?

I assume 3 in 1 oil will work to lube the bushings (forward and back).  I don't think i saw anyone mention what i should lube with in the thread.  Sorry if i missed it.  Also i assume i would need to remove one of the X rods and the y carriage to do anything about the linear bearings?

Edit:. I now hate solidoodle.  I went and disassembled my y axis and re greased everything.  Still have y shifts.  Went to take out the front pullys to see if there was hidden damage and noticed they were attached with red threadlocker.  Unfortunately this was after I stripped the head.  Looks like I have to destroy the brackets.to get it off.  Why use threadlocker on such a delicate part... I know from experience that threadlocker turns abs into dust.  I can't even print rep!acement brackets. 

So.. now my choice seems to be give up and buy another printer or buy some more brackets from someone and break out the blowtorch with no guarantee it will fix anything. 

So much for my laser engraver project...

anyway, his design allows you to align the motor in the Y and Z direction. even without an oldham style coupler I imagine you can get close. long term you will want an oldham coupler though yes, but it should not substitute for extreme misalignment.

Z alignment is handled by the teardrop holes in the frame. Y alignment is handled by moving the motor left and right and re-tightening the screws.

Here is the link I was following:

http://tomhorsley.com/hardware/solidood … irect.html

http://us.misumi-ec.com/vona2/detail/11 … s2products

you should put 2 of the original Y motor screws diagonal from each other to hold the back together. 2 of the original Y motor screws diagonal from each other in opposite holes to mount the motor itself.

https://www.youtube.com/watch?v=gW2rf-G … e=youtu.be

So
1)  I can just pop off the back of the motor.  That doesn't sound right
2) It wobbles

Is this normal, and if not, what adjustments should I make?

The Y motor silver casing apparently is just pushed on without the frame screws that hold it in place.  If I screw the original m3-33mm length screws that held it on the printer, they don't go all the way through.  Looks like I'll need some 43mm length m3 screws, which I don't think I saw at home depot.

When the back came off, some of the washers inside the motor popped out.  I noticed they were bent to shit.  This makes me wonder if I need new washers in there as well (or possibly a new Y-motor?). 

Edit:  Well, looking closer at one of the washers, it is like a sin wave, so maybe this is by design... :\

So I can print (so far), and I've got the new rod and bearings in, taking out the old rod and bushings.  When I printed the Y-Mount, the one here:
http://www.thingiverse.com/thing:593006

I take it I will need to order 4 more screws to screw the motor onto the mount?  Do I need to screw the top of the mount into the frame, or will the bottom four screws (that previously held the motor in place), be enough to keep the mount in place?