EEVblog Electronics Community Forum
Electronics => Open Source Hardware => Topic started by: bitman on December 02, 2018, 02:58:06 am
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On https://www.raspberrypi.org/documentation/hardware/raspberrypi/schematics/rpi_SCHE_3b_1p2_reduced.pdf (https://www.raspberrypi.org/documentation/hardware/raspberrypi/schematics/rpi_SCH_3b_1p2_reduced.pdf) I cannot get the diagram to match what I see on my board. In particular, D5 is labelled to be SMBJ5.0A but the print on the "diode" says BUZ GP711 and I cannot find that anywhere. Testing the component as a diode fails - it has very little resistance (30 or so Ohms).
I am no longer able to power the RPI - I think the current got reversed from a "hat" - when I take the PI with nothing plugged into it, it takes about 0.5Amps before it goes to the full 5v and the USB plug and components right around it are very very hot within seconds (burning fingers hot) so there's a short or something like that. Measuring + / - shows 226K\$\Omega\$ - and since I see very little resistance on D5 I'm thinking that's the fault (and I cannot measure the forward voltage). The strange part is, that the component looks exactly like the datasheet for the SMBJ5.0A shows - but the print on it doesn't match (see picture attached).
I'm looking to identify the component and find a way to test it to see if it needs replacing.
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It is a ST SMBJ5.0A as the reduced schematics indicate. The ST datasheet for a SMBJ5.0A (https://www.st.com/resource/en/datasheet/smbj.pdf) says the marking is BUZ which matches up with what you see on the part. GP is the ST manufacturing location code. 7 is the year. 11 is the week.
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well, I should have known I was reading the wrong datasheet ..... thanks!