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Need help. I'm trying to recover an old Toshiba T1200XE laptop and it seems the onboard PSU has a problem. One SMD looks damaged and I think it's better to replace it. I'm pretty sure this happened because old capacitors have leaked and electrolyte leaked to the board which provoked a short circuit. Sign on SMD looks like 222 where first digit underlined and second overlined. PSU board ID: 36M743776G. Size of this SMD 3 x 1.6 mm. Picture of it on board:

p.s. similar topic here

enter image description here

In the Google I've found another picture of this SMD and there different sign 22Y

enter image description here

Please help to identify this SMD and find some analogue of that SMD to replace it. Thank you!

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  • \$\begingroup\$ upvote for posting a textbook example of a quality picture \$\endgroup\$
    – jsotola
    Jan 24, 2021 at 4:09

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This site says 22Y is a 22 volt Zener diode, and here's a datasheet that includes 22 volt Zeners having marking codes of 22, 22X, 22Y, and 22Z.

Trace the circuit around the device. If only 2 of the 3 pins are connected, or 2 of them are joined together, then it is almost certainly a diode of some type.

BTW it looks like several devices on the other side of the board (power transistors?) have 'dry' (cracked) solder joints, eg. the flat pins to the left and above the circle.

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  • \$\begingroup\$ Thank you for response, Bruce. I have checked the components on other side of PSU. They are look good. No cracks, dark spots or bumps. Signs on them J182. Google says this is a P-Channel MOS FET. I've counted 4 of them on the board in different places. p.s. Currently waiting for new set of capacitors and after that and after replacement 22Y diodes will try to turn it on and firstly check the output voltage. Accordingly to maintenance manual should be on output 12, 5, -9 and -22v. \$\endgroup\$
    – Max
    Jan 24, 2021 at 20:21
  • \$\begingroup\$ @Max He's saying that the solder joints look bad. It could possibly be that they were soldered by hand and using RoHS solder, which makes the joint look grainy. I'd be more concerned by the blobs on some other components where the joint has not wet correctly. Looks like a PCB issue with too much ground plane etc. Anyway, if you are comfortable with SMD soldering it doesn't hurt to flux various fishy-looking joints and then just re-heat them. \$\endgroup\$
    – Lundin
    Jan 25, 2021 at 11:20

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