Duracell CEF14N NiMH battery charger - need R28 value

• Duracell CEF14N NiMH battery charger - need R28 value
  Posted by Hogwild on 18 Nov, 2017 00:03
• Hi friends:
  
  My Duracell CEF14N (the old model, looks like this) died a while back. See attached image for photo.
  
  I opened it up and first noticed a bulging cap. Shame Duracell! I bought some replacement caps. Unfortunately, I didn't notice until now that the R28 surface mount resistor was burned. When I touched it, it disintegrated into dust and so now I can't see the value of R28.  I Googled, but found nothing at all on this charger, maybe because it's older.
  
  Does anyone know what value and physical size that resistor is? I'd like to save this thing if I could. It was a great charger when it was working.
  
  Thanks in advance.

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• #1 Reply
  Posted by Hogwild on 18 Nov, 2017 21:28
• Update: It looks like the R28A resistor across from it also may be blown. It's hard to tell. I will report back my findings as soon as I get them.
• #2 Reply
  Posted by IanB on 18 Nov, 2017 22:16
• If it can only charge batteries in pairs I think I would retire it and replace it with a charger that monitors each battery individually. Pairwise charging was a cost saving measure that should not be needed in modern chargers.
• #3 Reply
  Posted by Hogwild on 19 Nov, 2017 03:54
• I prefer not putting things in the landfill. Plus, it's a challenge.
• #4 Reply
  Posted by Hogwild on 19 Nov, 2017 19:31
• IanB:
  
  Can  you point out any teardowns or analsyses of newer chargers which charge each battery individually? I'd like my next charger to last longer than this one.
  
  
  
  
  

  Quote from: IanB on 18 Nov, 2017 22:16

  If it can only charge batteries in pairs I think I would retire it and replace it with a charger that monitors each battery individually. Pairwise charging was a cost saving measure that should not be needed in modern chargers.
  
• #5 Reply
  Posted by IanB on 19 Nov, 2017 19:59
• Quote from: Hogwild on 19 Nov, 2017 19:31

  Can  you point out any teardowns or analsyses of newer chargers which charge each battery individually? I'd like my next charger to last longer than this one.

  
  Forum member HKJ has a webpage with reviews of many chargers here: http://lygte-info.dk/
  
  I personally own and use the Panasonic BQ-CC17. It is a smart, "overnight" charger which charges the cells individually and has good management of the charging process. I cannot say how long it would last, but Panasonic seems to be a reliable brand with quality products. I have other Panasonic chargers and they have all worked well (which is more than I can say for other brands of charger).
  
  HKJ has a review of it here: http://lygte-info.dk/review/Review%20Charger%20Panasonic%20BQ-CC17%20UK.html
  
• #6 Reply
  Posted by Hogwild on 20 Nov, 2017 03:12
• I noticed that SMD resistors R28 and R28a appear to be burned or singed. Damaged, at least. Also, capacitor C5 on the beige side seemed be bulging a bit. I have extra capacitors, but no resistors. If I get some resistors soldered in, I'll post back and share my results.
  
  Thanks for that site. Wow, that's unbelievable how many chargers and batteries he's tested.
• #7 Reply
  Posted by floobydust on 20 Nov, 2017 03:17
• Another method is to find the controller IC datasheet/app notes/eval board and see what values are used.
• #8 Reply
  Posted by Hogwild on 06 Dec, 2017 03:35
• Okay, I got it fixed. In my case, it was a capacitor. I took some photos and wrote a quick guide on iFixit.
  
  Duracell CEF14N nimh charger-not charging
  https://www.ifixit.com/Guide/Duracell+CEF14N+NiMH+Battery+Charger+-+Not+charging/100409