Chip identification - Page 1
Forum section: electronics / beginners

author: Shush
author_rank: Newbie
timestamp: October 25, 2022, 12:34:22 pm
content: Hi, I'm a novice with an interest in electronics, because Ive had some success repairing things a family member has given me a dead board to look at.I found several shorted components about one of them has me stumped as I can find nothing about it anywhere, it's marked BCEOD and is U1 in the picture.I would be grateful for any and all help to identify this chip.

author: DavidAlfa
author_rank: Super Contributor
timestamp: October 25, 2022, 01:05:30 pm
content: RY8120

author: pcprogrammer
author_rank: Super Contributor
timestamp: October 25, 2022, 01:14:34 pm
content: Quote from: DavidAlfa on October 25, 2022, 01:05:30 pmOops you did it again. Hooked into another threadOh dammed so did I

author: pcprogrammer
author_rank: Super Contributor
timestamp: October 25, 2022, 01:25:08 pm
content: Looking at the marking it might be BCE0D. So a zero instead of an O.Not sure if the RY8120 is the correct one, because the marking is BC, year, lot number code.For BC marking in sot 26 I found this onehttps://www.s-manuals.com/pdf/datasheet/r/t/rt9010_richtek.pdf

author: DavidAlfa
author_rank: Super Contributor
timestamp: October 25, 2022, 01:25:30 pm
content: that's why I'll be making davidalfa 2,3,4,5,6... usernames soonYes but this is a switching regulator, not a LDO, check L1!The bootstrap capacitor C3 seems to be going to pins 1&6, L1 to pin 6, R2/R3 feedback to pin 3, everything matches.

author: Shush
author_rank: Newbie
timestamp: October 26, 2022, 02:18:06 pm
content: Thanks for the input guys.It is a voltage regulator but there’s only 2 pins with voltage and they’re both at 12v which is the same as the input voltage to the board, every other pins shows a short.I’ll take a look at the part that’s been mentioned and go from there.

author: pcprogrammer
author_rank: Super Contributor
timestamp: October 26, 2022, 02:27:10 pm
content: Make sure to verify the circuit with example given in the datasheet. Most often you can match up that way when more then one type of component is found based on the SMD marking.Edit: With the 12V being the input voltage and seeing it on two pins might mean that it is shorted internally and the 12V killed more components on the board.

author: DavidAlfa
author_rank: Super Contributor
timestamp: October 26, 2022, 02:45:37 pm
content: R2 has a suspicious black line on it, could be cracked.Those resistors useEIA-96marking.Don't measure them in-circuit, desolder one side and slightly rotate it so one side becomes isolated.05D = 100K18C = 15KIf broken, the controller feedback might read 0V, setting the output to 100% and blowing everything up.The resistor ratio is a bit strange:0.6*(1+(100/15)) = 4.6VWhat are those wires instead L1?You cannot measure the voltage without it, all you will read is 12V spikes and kill everything connected to it.

author: mariush
author_rank: Super Contributor
timestamp: October 26, 2022, 05:28:58 pm
content: You should also reflow the components around the chip ... solder on tops of C1 and C2 don't look so good to me, and I'd reflow the inductor and the ceramic capacitor right to the right of the U1 chip.

author: Shush
author_rank: Newbie
timestamp: December 15, 2022, 11:31:56 am
content: Hi guys, an update on this.I ordered the chip as advised and reflowed the resistors, they were giving the correct readings so I reused them.Just fired it up on my ben power supply and its working.A massive thanks to everyone that commented, it's very much appreciated.