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- A sign of the times ... - 2 Updates
- Which device is causing this? - 1 Update
- Tips for Discharged Nokia BL-5J 1430 mAh 3.7 Battery? - 2 Updates
| jurb6006@gmail.com: Dec 07 09:00PM -0800 >"Far as I am concerned, Service Manuals are mainly for light entertainment >reading. " You forgot to mention the errors. I mean on the perfect copies. The really nice ones with no pixelisation or anything. Yup, the wire has 12 volts on it here, but over there has zero. Happens all the time. You know it almost seems like they want nobody to b able to fix this shit, or be able to understand how it really works to fix this shit. and that is not just Walmart shit either. |
| "William Sommerwerck" <grizzledgeezer@comcast.net>: Dec 08 06:42AM -0800 One of the ways companies keep down the price of their cheaper products is to cram everything -- including hundreds of SMDs -- onto one PCB. Such products are all-but unrepairable. |
| etpm@whidbey.com: Dec 05 04:32PM -0800 >because they can follow detailed instructions that someone else has >written down for them. > Michael Well Michael, I guess you're right. I don't know a lot about electronics but I can diagnose stuff. I tried to keep the subject header short which is why it was ambiguous. You are also correct that repair can be just unplugging (or unsoldering) a component or a whol system of parts, like the complete power supply. Since I donm't know a whole lot about electronics I asked here for information that would help me diagnose the bad part or device. Probably I should have posted the question in the basic electronics group too. In the end though I though Jamie was being a little flippant. I felt my reply was a little flip too. Now it has gotten out of hand. A more appropriate reply from me would to have asked Jamie if he was being flippant. If he wasn't then his answer would have been what he thought I was capable of, not an unwarranted conclusion. Cheers, Eric P.S. This weekend I will attempt to find the bad cap, unsolder it and replace it with a new one. If that doesn't work then it's time for Jamie's solution. |
| "Ian Field" <gangprobing.alien@ntlworld.com>: Dec 07 08:58PM "mike" <ham789@netzero.net> wrote in message news:m5rovc$su8$1@dont-email.me... > It probably has a protection circuit. > If it has been discharged below threshold, it's turned off and cannot > be turned on externally. You'll see zero volts and high ohms. My usual salvage source sometimes gives up the odd mobile phone - in every case so far, the battery has been discharged dead flat. Most were revived by "tickling" the contacts with the leads from an old fashioned car battery charger. The next stage involves a universal lithium charger from the Lidl discount store - it has automatic polarity sensing, so it won't start charging the cell till you've put a spark of life into it. When that indicates fully charged, its time to see what the phone makes of it. The only failure so far was was a dodgy Motorola knock-off from Ebay. |
| mike <ham789@netzero.net>: Dec 07 06:09PM -0800 On 12/6/2014 12:07 PM, KenO wrote: > mike, > "educational purposes only" have you taken a cellphone battery apart? Yes, in virtually every used cellphone I've bought. Protection board is usually held on the end of the cell by the plastic over-wrap. > Do you know of any websites that give reliable info concerning cellphone battery protection circuits? > Thanks > Ken Problem is that there are many different types of protection circuits/chips. Individual battery details are usually not available to the public. Check the numbers on the protection chip. bq29311 is one such chip. There are others in the BQ series. Another thing that happens with laptop batteries is the fuse. The fuse has a heater in it. When the protection chip decides that you should no longer have use of your battery, for whatever reason, it activates that heater and smokes the fuse. You're dead in the water until you replace the fuse. Never seen one on a cellphone battery, but all mine are OLD. If the cell is completely discharged, you can't measure the volts to determine which is the + terminal. It's probably not the one you'd expect by looking. Make SURE. I can't overstress the safety aspect. You cannot assume that the designer of the system followed reasonable design procedures. I had a Dell laptop that had nothing but a fet between the charge port and the battery. Current limit was in the wall wart. Charging it from a voltage source burned a hole in the motherboard. I got lucky. If the FET had failed shorted, it would probably have exploded the battery. I had a battery start sizzling. Got it out the front door before it exploded. I never found the guts of the cell that went boom. Nothing drives it home like asking yourself, "Hey, what are those drops of hot electrolyte doing on my glasses?" What's a battery cost? What's the value of your eyesight? Does your kid ever use your phone? It's just not worth it. |
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