Hi everyone,
I'm hoping to get some help with a circuit I'm working on. It's a digital-to-analog converter (DAC) circuit.
Unfortunately, the circuit seems to be stuck! No matter what digital value I give it, the output voltage coming out is always around 11 volts.
I've tried troubleshooting by replacing the op-amp (OP07CP), and a transistor (2N5401), but that didn't fix the issue.
I've been trying to understand the circuit by analyzing its components and how they're connected (reverse engineering). This is my attempt at a schematic based on what I've found (attached).
I would be incredibly grateful if anyone could offer some insights into why the output voltage is always stuck at 11 volts, even though the digital input changes. Any advice would be greatly appreciated!
![Schematic_DAC-Molleton_2024-03-26.png Schematic_DAC-Molleton_2024-03-26.png](https://forum.allaboutcircuits.com/data/attachments/306/306108-c3ba7057b4ecb3ba40ae2490f58c9044.jpg)
![IMG_20240319_150728.jpg IMG_20240319_150728.jpg](https://forum.allaboutcircuits.com/data/attachments/306/306109-185149b5a632e10bb2afcc7cae38f137.jpg)
![IMG_20240319_150744.jpg IMG_20240319_150744.jpg](https://forum.allaboutcircuits.com/data/attachments/306/306110-a37f9cde826728472d697da87ed4c244.jpg)
I'm hoping to get some help with a circuit I'm working on. It's a digital-to-analog converter (DAC) circuit.
Unfortunately, the circuit seems to be stuck! No matter what digital value I give it, the output voltage coming out is always around 11 volts.
I've tried troubleshooting by replacing the op-amp (OP07CP), and a transistor (2N5401), but that didn't fix the issue.
I've been trying to understand the circuit by analyzing its components and how they're connected (reverse engineering). This is my attempt at a schematic based on what I've found (attached).
I would be incredibly grateful if anyone could offer some insights into why the output voltage is always stuck at 11 volts, even though the digital input changes. Any advice would be greatly appreciated!
![Schematic_DAC-Molleton_2024-03-26.png Schematic_DAC-Molleton_2024-03-26.png](https://forum.allaboutcircuits.com/data/attachments/306/306108-c3ba7057b4ecb3ba40ae2490f58c9044.jpg)
![IMG_20240319_150728.jpg IMG_20240319_150728.jpg](https://forum.allaboutcircuits.com/data/attachments/306/306109-185149b5a632e10bb2afcc7cae38f137.jpg)
![IMG_20240319_150744.jpg IMG_20240319_150744.jpg](https://forum.allaboutcircuits.com/data/attachments/306/306110-a37f9cde826728472d697da87ed4c244.jpg)