Need advise on where to get a replacement breakout board for the YOOCNC X4JKB.  Any & All help will be greatly appreciated.

Although not identical to the one you mentioned CNC4PC do a good range of breakout boards so you should be able to select a comparable replacement. http://www.cnc4pc.com/Store/osc/index.php?cPath=33&osCsid=074e2c480e07efcff985cce3938884a5

Tweakie.

I've have exactly same problem as you ith my new CNC3040 from amonstar after one week ... only run 5 hours when Z axis becomes crazy !!!

Idecide to look at everything and after complete cheking i saw that YOOCNC X4JKB card send wrong code to Z axis. So i decide to buy new parrallele card for CNC.

I buy 5 Axis CNC Breakout Board For Stepper Driver Controller. Runs PERFECT !!!

See link below : http://shop.ebay.fr/i.html?LH_TitleDesc=0&_sacat=See-All-Categories&LH_PrefLoc=2&cmd=Blend&_nkw=5+Axis+CNC+Breakout+Board+For+Stepper+Driver+Controller&cmd=Blend

PLUG AND PLAY with all CNC from AMONSTAR ! Nest quality and many option with it !!!

Excuses me for my english (I am french)

D.