I was awake sewing last night later to pause as I've accidentally break the needle. So, I changed the needle right then, however I found out the the thread orientation was out of order.
The upper thread looks OK, but the lower thread was disaster (berbulu-bulu!!!).
The manual doesn't state clearly on how to adjust the thread tension but I figure out on how to adjust them from one of the books that I owned. So, I am glad to share this with you.
To adjust the upper thread tension:
To adjust the lower thread tension:
OK. I hope thread tension does not going to put you in tense.
*This applicable to all sewing machine that use bobbin cap (not for the new drop-in bobbin's sewing machine).