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Forum Index : Microcontroller and PC projects : Computer Power Suppy - Release of Magic Smoke

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circuit
Senior Member

Joined: 10/01/2016
Location: United Kingdom
Posts: 292
Posted: 11:47am 06 Aug 2021
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Sony Vaio computer power supply - 19.5V, 6 Amps (power brick); circa 10 years old - failed with a bang.  I opened the thing up to find the main IC - labelled IC1 on the circuit board - with its casing blown apart, releasing the magic smoke.  Quite a catastrophic failure of the IC casing; under a stereo microscope I could see striated marks on the adjacent silicone pad, the orientation directed to the point of failure on the IC, indicated by the angle of the white arrow in the photograph.  This i.c. failure rather surprised me and hence this note.  Any opinions as to why this chip should fail so violently?  Tins whiskers came to mind.  No other components show any sign of failure.  The red arrow shows what I think is a solder point for the heat sink for the chip with marked heat discolouration of the resin coating.  

 
phil99

Guru

Joined: 11/02/2018
Location: Australia
Posts: 2831
Posted: 12:06pm 06 Aug 2021
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I have seen that on mains switching chips, but that looks like its on the LV side. Most unusual bot with the sunroof open the cooling will be better! ;-)
 
Mixtel90

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Joined: 05/10/2019
Location: United Kingdom
Posts: 8297
Posted: 04:49pm 06 Aug 2021
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At first I wondered if it was a chip with a built in mosfet to drive the transformer but the tracks all look too close together to have the incoming DC on them.

This PSU is no more. It's gone to meet its maker. :(
Mick

Zilog Inside! nascom.info for Nascom & Gemini
Preliminary MMBasic docs & my PCB designs
 
CircuitGizmos

Guru

Joined: 08/09/2011
Location: United States
Posts: 1427
Posted: 11:30pm 06 Aug 2021
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  phil99 said   Most unusual bot with the sunroof open the cooling will be better! ;-)


It'll never get hot again!
Micromites and Maximites! - Beginning Maximite
 
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