Error 5 on my machine

bunching up of the thread at the bobbin indicates that the needle thread tension needs adjustment

When did you last have this serviced?

try adjusting the top thread tension
also try changing the needle-one that is for the fabric and thread
if that doesn't help, then a repair shop would be a good idea

I just found your question, so I'll try to help you,
you said you just had the machine serviced and it's still
showing the error 88, is this error why you took the machine in to
be serviced for?
if it is then I suggest taking the machine back to the repair shop
and tell them it wasn't fixed correctly.
I've had other people say that they've took their machine in to be
fixed and then brought the machine home and it still had the same
problem so that means that they didn't fix the machine ..
have you tried changing the needle--needle that is correct for the
fabric being sewed
try rethreading the machine top and bobbin
also try using a different bobbin
make sure the top thread has not come off the thread take up lever
make sure the top thread is not wound around the spool pin
make sure the bobbin is turned the correct way
do you have a manual for the machine?

The needle thread breaks
1. the needle thread is not threaded properly
2. The needle thread tension is to tight
3. The needle is bent or blunt
4. The needle is incorrectly inserted
5. The needle thread & the bobbin thread are not set under the presser foot when starting to sew
6. the threads were not drawn to the rear after sewing
7. The thread is either to heavy or to fine for the needle

this is what my instruction book says

Lo---a button is pressed when the machine halts due to overload
wait for at least 15 seconds to recover
if thread jamming causes overload, remove the tangled threads

As a general rule, domestic machines don't like buttonhole twist, that heavy yellow thread you see on the RTW jeans. Sometimes you can put it through the bobbin but use a regular weight thread on top but this means sewing upside down as you'll want the yellow on top. And lots of machines dont like different weight thread top and bottom so it just makes for awful stitching anyway.

Best solution to top stitch jeans is use a regular weight thread, large size jeans needle but thread up two spools of thread on the top with both threads going through the same needle eye. It still may not solve the problem though.

To your machine, firstly change the needle as it may be bent. Then unthread the machine and manually turn the flywheel through a stitch cycle and listen carefully, if you still hear a noise as the needle touches the rotary hook, you've knocked the timing out. Service man visit time.

Probably if you check the manual, it will say 50 weight thread, and you'll need to stick with that in the future.

Those big industrial sewing machines that they top sew jeans on are very different to a domestic SM, many make a chain stitch or fell the jeans seams and are very heavy duty.

check to see if the twin needle are damaged
check the bobbin & make sure the bobbin case is thread correctly
needle & thread may not be compatable
here's how to check
Cut 6-8 inch piece of thread of the spool you are going to use for your project
Take the needle you are going to use for the project
& insert the thread thru the eye of the needle
& lift one end of the thread to a 45 degree angle
& if the needle is the right size for the thread it will slide down the thread
But if the needle hangs on the thread you need one size larger needle for the thread

You have to read your manual carefully, then rethread your machine because it is not threaded right. If, you need extra help call 1-877-276-8437 until 5:45pm est

Sounds like you have the upper threading wrong, or you have the upper tension set too loose, set it to 5.