Since the light is one of those 12v things from my 1972 Fiat Spider it requires the transformer to drop the 110v to 12v
Here are photos of both the Nora and the Miranda.
The light is chassis grounded so there is only one wire going to it
Schematic
I removed the auxiliary outlet on both because the cord was deteriorated.
Tom, thank you for this info. I was looking for the same info for 2 parts machines that need rewiring. This helps greatly.
ReplyDeleteGlad it helped, I'm not an amateur but I found this wiring confusing, and after blowing a hole in one of those 12v lamps I decided trial and error was not going to be fruitful
DeleteI understood the stepdown transformer, but didn't realize the "light" switch as actually an on/off switch, but makes sense. Since mine were also with mismatched motors, I was wondering if the transformer was enough to vary speed as I'm used to a motor with a different brush offset for a separate speed. Seems like the transformer is not an ideal way to vary motor speed. My early BU Nova didn't have that option. Many thanks, again.
ReplyDeleteYes I think that using a transformer to step down the top speed may be the cheapest and therefore the least desirable way they could have gone. A servo with a real variac would be nice. They didn't have cheap electronics back then!
DeleteThanks for this post.
ReplyDeleteI'm working on a supernova that has some trouble with the transformer, and it looks very similar to what you have in your machine. Do you know the voltage and amperage values the transformer should put out?
Interesting question, I will have to open up one of my machines and take some readings, may be a week or two.
DeleteThere certainly are no markings that I have seen and from what I have noticed the Hi - Low speed diff is very minimal I wonder if hooking it up direct (eliminating the Low altogether) would be an option
With 115vac 60hz across the black and purple, 12.8vac across the blue leads. It is a filament transformer which were common in the the day of cheap vacuum tube thermonics That is the standard cathode heater voltage. Today, it would be a capacitor dropper and LED light. The resistance between the purple and orange is 9 ohms.
DeleteThank you SO much for making this wiring diagram! I was just given my grandmother's Nora and someone had cut the wires off at some point, probably 40 years ago, so I was a bit confused as to how to install the new wiring.
ReplyDeleteDo you happen to know where to get the fly wheel belt by any chance? I'm in Arizona so mine is dry rotted.
Glad to be of service.
DeleteThe belts are common start with the assortment pack at Joann's ; anything that fits and doesn't slip is a belt, nothing special.
Hi I am looking for a necchi bu mira motor, not having any luck on the internet. can you help?
ReplyDeleteHi Tom, I am trying to wire my BU Mira (the diagram you gave is very clear and I was able to wire it). Great instructions. Only, I just get light and not power to the foot pedal end. Is there any quick thoughts you might have on what might have gone wrong (the inside of the motor / transformer area was good - I did not touch it just verified with your diagram and it matches). the only thing I did was add the cable for the motor end on the 3 pin plug area. Would greatly appreciate if you have any thoughts on this. Thank you very much.
ReplyDelete#can anyone help with a wiring problem with a Necchi Lydia 544 sewing machine?
ReplyDeleteThis is exactly some of the info I need. The wiring appears to be the same as my Nora. On mine, the transformer is roasted. Charred black. Is there any way to replace the transformer? No parts seem to be available at all. Or possibly make it work with more modern parts? Does it have to have the transformer to work?
ReplyDeleteSorry for the barrage of questions, but I'd really like to get my od machine up and running again.
Thanks
Bert