Hello everyone,
I have a V4 I really enjoyed using, which suddenly stopped working last night. After it froze my machine for 1-2 seconds, the dongle was no longer recognized. I checked with multiple machines running Linux and Windows.
Since the V4 hit EOL, I thought I’d give repairing a try. I checked the board for shorts and measured 18 Ohms between the USB power lines. I’m guessing this is enough to trigger the over-current protection on my computers. Next, I injected voltage into the USB power lines using my lab supply, starting at 1V and increasing gradually. At 3V, the component U4 next to the large Al-polymer capacitor got hot, which makes me think this is the broken component. I took the risk and injected 5V, then tested the VIN pins of the RTL2832U. All showed nominal voltages.
My question: does anyone know the specifications of component U4? The label reads “A07” or “AD7”. Measurements are roughly 1.2 mm x 1.2 mm. In the original “Choose a genuine RTL-SDR Blog V4” figure, it’s marked as “Improved power supply (reduced phase noise)”.
I imagine that over time there will be more people with dongles that are somewhat broken. It might be nice to collect information about the components used, so users can attempt repairs.
All the best,
Nils