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Corrosion Caused Repeated Failure Of PWM In Battery Charging SMPS DYSON SALOM 17530-01

By Jestine Yong on July 30, 2021

This SMPS was brought to me in May, 2019 by a technician. The name and model recorded by me was Dyson Sec Salom 17530-01. The complaint that time was failure of its PWM TNY278PN. That time, I found the IC had blown along with the rectifier diodes and fuse. I used a bridge rectifier and restored the power supply section and placed the new PWM IC on a socket. It was working very well for quite some time. But according to the customer, he had to replace the PWM often, upon which he connected an SMPS module in place of the PWM. But afterwards, that too failed. So, he brought it to me now in July, 2021. Following look of the primary section of the PCB is self-explanatory for the reasons of failure:

So, I cleaned and rubbed the primary side of the PCB and made it shining and retouched the entire area with fresh solder. ESRs of caps were ok. No other components were found defective. Ring testing was also found ok.

Retouched the secondary side with fresh solder. Checked the components in the secondary and surrounding the following charge control IC:

Then replaced the PWM with TNY177PN that I had in stock. Connected power and found the outputs as 16.5V and 24.5V, which seemed to be accurate as per information that I could gather from the following link:

17530-03 SSW-1864EU-A Dyson 16.75V 24.35V 348mA AC Power Supply Adapter Charger [17530-03 SSW-1864EU-A Dyson 16.7] – $35.99 : power adapters, power adapters,power supply,ac dc adapter (adapter-plaza.com)

Mission accomplished and satisfaction got added to its collection. Here is the picture of the only one component that got replaced:

This article was prepared for you by Parasuraman Subramanian from India. He is 72 years old and has more than 30 years’ experience in handling antique equipment like Valve Radio, Amps, Reel Tape Recorders and currently studying latest tech-classes conducted by Kerala State Electronics Technicians’ Association. He has done graduation in BBA degree, private diploma in Radio Engineering and retired as MD of a USA company. Presently working as Consultant to Hospital and other institutions.

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11 Comments

Albert van Bemmelen

July 30, 2021 at 1:13 pm

Those TNY chips too often fail and are the reason of these defects. Like in washing machines and dryers that one would start to question if they maybe are designed or manufactured wrong? And when they collapse they often also have a serie fuseresistor that goes with them.

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- Parasuraman S
  
  July 30, 2021 at 5:50 pm
  
  Yes, I have seen its failure in many other devices as well! Many thanks for your comments!
  
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Yogesh Panchal

July 30, 2021 at 1:45 pm

Good Job! Sir

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- Parasuraman S
  
  July 30, 2021 at 5:50 pm
  
  Many thanks, dear Yogesh!
  
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Babu M S

July 30, 2021 at 10:10 pm

Fantastic job sir. From this article learned the corrosion effect on power ic failure.Thank you very much for sharing.

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- Parasuraman S
  
  July 31, 2021 at 8:01 pm
  
  Many thanks for your comments!
  
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Waleed Rishmawi

July 31, 2021 at 11:59 am

Good job my friend. Thanks for sharing

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- Parasuraman S
  
  July 31, 2021 at 8:02 pm
  
  Many thanks for your comments!
  
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Parasuraman S

July 31, 2021 at 8:02 pm

Many thanks for your comments!

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Yogesh Panchal

August 7, 2021 at 12:59 am

Sir, To insulate those traces there is solution which easily available now called "Solder Mask" which is cured by UV Light with good result.just apply thin layer on trace and hold under the UV Light for 1 Minute and done.

https://roboticsdna.in/product/mechanic-10ml-green-uv-solder-mask-pcb-bga-paint-prevent-corrosive-arcing-soldering-paste-flux-cream-welding-fluxes-oil/

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Christophe

November 9, 2021 at 2:53 pm

Great Job !!!
I have a Problem with the PCB (a Resistor is missing) and the Charger doesn't work properly (LED is blinking - Cold/Hot Battery - Battery = OK).

Does Anybody can tell me the value of the missig Resistor R208a (paralel to R208 = 24[kOhm]?

Thank you very Much !!!

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