| Electronics > Repair |
| BERNINA power supply board (Switch Mode) issue diagnosis and beyond (fixed) |
| << < (4/15) > >> |
| inse:
0.56 Ohms for sure, it’s a current feedback shunt. Checking the solder joints is always a good idea though those look as shiny as you wouldn’t see them anymore today. |
| Sorama:
I do see some suspicious rings on some solder joints. |
| max.wwwang:
Here's the schematic of the upper section. Excuse my perhaps non-standard (incorrect) use of symbols (however feel free to point out). |
| max.wwwang:
--- Quote from: Sorama on December 20, 2024, 08:22:56 am ---I do see some suspicious rings on some solder joints. --- End quote --- Thanks. Had a close l but didn't find any obvious problems. Which ones you find suspicious? |
| inse:
Nicely drawn schematic, though boring. Btw, R52 is 160Ohms and R53 150Ohms. The circuit around the TL431 is providing the feedback for the voltage regulation of the 5V rail. The other voltages are determined by the turns ratio. |
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