Where are the carbon brushes on a Bernina 830 Record 1970s sewing machine? In foot pedal or motor?

Most likely your machine has carbon brushes that are worn and need to be replaced. (intermittent start-stop is a strong indicator. Not sure on your 801, but a lot of the older Berninas have carbon brushes in the motor (I've replaced them on an 830), Newer models have them in the foot control. Once you locate them, you can order replacements for probably less than $20 and your machine will run like a champ! There are web sites and videos that have instructions.

sewing machine carbon Google Search

take it in for a service
could be foot pedal problem or motor problem

The 830 models varied so I'm not sure. My machine looks like this:

Bernina 830 sewing machine feet pedal accessory box table instruction...

If you scroll over to the photo of the motor, there is a white plug which pulls out. Underneath, there is a screw. The carbon brush may be there. However, some 830s had the speed switch on the machine (right above the knee control) and others have it in the foot pedal.

I found the following information in my computer files that may be helpful: Bernina 830 Motor Brush Replacement

My machine is actually a Bernina 830 (mechanical 34 years old) I need to know how to get the housing off the motor so my hubby can replace the brushes

Re: sewng machine motor housing

DISASSEMBLY TO INSPECT OR CHANGE BERNINA 830 MOTOR BRUSHES:

Remove the big plastic cover piece on the bottom of the machine with the single screw in the center.

Remove the machine's end panel by removing the single silver screw from underneath the bottom middle of the side panel. Pull the bottom of the side panel out and down to remove it. It comes off easily.

Remove the two screws under the motor assembly (silver screws with black washers).

Swivel the motor assembly enough to remove the belt.
There is a another plastic panel on the motor assembly over the motor itself. Remove the two phillips head screws to remove this panel.

At this point you can see the commutator and inspect the "business" ends of the brushes. (In our case, one brush was almost gone and there was nothing left of the second brush except the spring!)

You can then slide the motor out of the housing. I pushed on the motor pulley and pulled on the other end of the motor with pliers. The motor comes out rather easily, but be careful not to disturb the wires any more than necessary.

With the motor exposed, unscrew the caps over the brushes and remove the brushes.

Our motor's commutator looks significantly worn and the motor may need to be replaced.
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FWIW, if your machine hasn't been oiled for a long time, you should probably take time to do that. When the old oil solidifies, it sticks the moving parts together. Forcing the motor to try to run the machine can damage the machine. Use fresh good quality sewing machine oil or (I use) liquid Tri-Flow Synthetic Lube and apply a couple drops every place metal rubs on metal. (Wiggle the handwheel and watch where things move.) Do NOT oil belts, synthetic gears, cams.



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could be
more likely a problem in the speed control of the motor or the motor itself ( they have brushes )
take it in for a service and proper diagnosis.

Perhaps carbon brush? If it is worn down and no longer making contact, it will not work.

If the motor is trying to run but not able to, then the machine is most likely seized due to old oil and no regular maintenance.

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It could very well be the carbon brush. It is generally a piece of soft carbon (like pencil lead) with a spring on the end which applies pressure. When the carbon gets worn down, it does not make consistent contact. Depends on your machine model. I've replaced carbon brushes on the motor of an 830 Record, but I had to replace something in the foot control. Do not despair. The replacements can be found for ~ $12-15. Available multiple places. Just be sure they will fit your machine.

2 Bernina Carbon Brushes for All New Style Machines eBay

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Be sure that you regularly clean and oil your Bernina. If not oiled regularly, the old oil turns to varnish and actually freezes the parts. Some people believe something is wrong with the motor or foot control, when really it just needs some TLC to keep it running smoothly.

May be one of several issues--depends on the model Bernina. Could be a problem with the foot control. I had to replace a carbon brush in the foot control of my 930. (A new foot control could cost over $160!)

Repair Bernina Type 290 Foot Control Pedal
http://sewing.patternreview.com/SewingDiscussions/topic/92721
https://tv-sewingcenter.com/bernina/bernina-830-fire-hazard
Sewing Foot Control Replacement

Or some machines (mostly older models, ie 830 Records) have carbon brushes on the motor that wear with age. Once they've worn down, they no longer make constant contact giving you the "intermittent" issue. I've replaced carbon brushes on some older Berninas--usually found somewhere around the motor (look for a screw or knob on the motor). You can buy replacements a lot of places. I've purchased them on eBay.

Sewng machine motor housing

How to fix replace Bernina Record 830 sewing machine motor capacitor...

Where are the carbon brushes located on Bernina sewing machine located It...

Carbon Brush Bernina 324250080 (make sure it will fit your model)

http://artisanssquare.com/sg/index.php?topic=3040.30;wap2

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your motor is going out. time to replace or rebuild your motor. both are high skill and should be attempted by a professional. take it to your nearest bernina shop.

Hi!

Here is the manual to a similar Bernina sewing machine.
Hope it will help you!
https://manualsbrain.com/en/manuals/807311/?page=205