I'm not specifically familiar with the 830 model, but all the other Berninas I've dealt with are very similar.
First, disconnect the power cord from the wall socket - safety first!
The housing for the lamp is in the hinged piece at the left (needle) end. It's hinged at the back (two hinges, one above the other like a door) and it's simply a matter of placing the palm of the left hand over the lamp switch with the thumb on the front above the needle and the tips of the fingers at the back of the machine, then opening the housing by twisting it away from the body of the machine from the front. It's held closed with a spring clip, so a little pressure may be required.
Once opened, the lamp and its holder are easily accessible. Remember the lamp is probably a bayonet fitting, so a little pressure to push the bulb into the contact springs and a slight twist in the same direction as you would turn a screw to undo it, and the lamp should come out. Avoid too much pressure on the lamp, as the glass part can part company with the metal base. If it does break, getting the metal base out is a bit of an issue, but it can usually be achieved with a pair of long-nosed pliers. Be very careful not to break the lamp holder - they can become quite brittle.
Having obtained a suitable replacement lamp of the same fitting size and wattage (most are 15 W), fitting it is simply a matter of pushing the lamp base into the holder and twisting it to lock it in place, then closing the housing.
Answers & Comments
I'm not specifically familiar with the 830 model, but all the other Berninas I've dealt with are very similar.
First, disconnect the power cord from the wall socket - safety first!
The housing for the lamp is in the hinged piece at the left (needle) end. It's hinged at the back (two hinges, one above the other like a door) and it's simply a matter of placing the palm of the left hand over the lamp switch with the thumb on the front above the needle and the tips of the fingers at the back of the machine, then opening the housing by twisting it away from the body of the machine from the front. It's held closed with a spring clip, so a little pressure may be required.
Once opened, the lamp and its holder are easily accessible. Remember the lamp is probably a bayonet fitting, so a little pressure to push the bulb into the contact springs and a slight twist in the same direction as you would turn a screw to undo it, and the lamp should come out. Avoid too much pressure on the lamp, as the glass part can part company with the metal base. If it does break, getting the metal base out is a bit of an issue, but it can usually be achieved with a pair of long-nosed pliers. Be very careful not to break the lamp holder - they can become quite brittle.
Having obtained a suitable replacement lamp of the same fitting size and wattage (most are 15 W), fitting it is simply a matter of pushing the lamp base into the holder and twisting it to lock it in place, then closing the housing.