My Sewing Machine Keeps Jumping it's Timing

Hi Lisa,
"A loud pop" whilst sewing sounds as though a capacitor has blown probably in the power supply unit. I'd recommend that you take your machine to a Pfaff service shop to have it serviced.
To reset the timing on a sewing machine is a specialist job. To give you an idea of what it entails on a mechanical machine (your machine is electromechanical) have a look at this video
Good luck :)

Yes, very difficult. Shaft has to be pulled out. Many different kinds of timing and clearances have to be reset. It's a job best left to a really good sewing machine mechanic. Check around for one with a good reputation.

This sounds less like timing, and more like a threading issue.
Make sure the thread is properly in the tension disks in the top of your machine.

Breaking threads isn't necessarily a timing problem. Check for burrs.

A broken needle can put your timing out, you need to find a sewing machine tech...

Hi There, Try uploading these free online manuals:

http://ismacs.net/free-sewing-machine-manuals-list.html

I hope that helps you out.

In case of adjusting sewing machine timing, there are twomain parts that you should follow.To adjust the hook needle timing on the rotary hook, first,remove the bobbin, bobbin carrier, and covers so you can see the movement ofthe hook. This may involve removing the needle plate for top loadingassemblies, or removing the hook cap from the front of the machine. Itoften requires the removal of the lower covers to reach the componentparts. Adjust as needed when doing sewing machine repair.Set the machine to a straight stitch at the defaultposition. Different models have different default positions including themost common far left and center positions. If no problems are perceivedin needle bar positioning, the default position will suffice. If thereare needle bar position issues, these need to be adjusted prior to adjustingthe timing. Follow proper sewing machine repair procedures.Rotate the hand wheel toward youuntil you see the needle reach its lowest position and begin its rise. Now lookfor the point of the hook as you continue rotating the hand wheel. Thepoint of the hook should strike inside the needle scarf above the needleby about 0.5mm. Sewing machine repair is vital for smooth operations.Check to see if the hook fails topick up the thread. Double check the needle bar positioning including thehook needle spacing. If these are appropriate and the point of the needlestill fails to pick up the loop thread, proceed to adjust the timing of thehook. Maintain regular sewing machine repair. Look for the lower drivemechanism. It may be a lower shaft with gears on either end. If this isthe case, look to the right end of the shaft for a gear with adjusting setscrews. Loosen and manually adjust the position of the hook. Tightly hold thehand wheel while turning the drive shaft to set the proper position. Retighten adjusting screws. Some models have timing beltsthat control the timing of the sewing machine. Look for a belt connectedon each with to drive gears. Look for work cogs on the belt. Inmost cases, you can reset the timing belt, without replacing it. If,however, the belt requires replacement you will need to do so. Loosen the drive mechanism on the right side to free the movement of the belt.Manually adjust the position of the hook to the needle and re-tighten set screws. This knowledge is vital for effective sewing machine repair.Once the timing has been reset,conduct thorough test sewing on the sewing machine to make sure everything isworking properly.Hope this will help you. Good Luck.

take it to a sewing machine repair shop, so the needle bar can be checked, & also the timing

Try searching for:

sewing machine timing

There are a lot of videos/web sites that offer instruction.