Thanks! Opening mine and applying a really good anti-corrosive ( fluid film - https://www.amazon.com/dp/B00B93ZXGS/ref=cm_sw_em_r_mt_dp_44SYFbT638Z8K ) that we used on downhole logging tools even. Stuff works great.
Chris Luppens > On Dec 4, 2020, at 5:55 PM, John Mechura via BVARC <[email protected]> wrote: > > > Greetings, > > I had noticed that my UV5R was taking too long to charge up the battery. The > red light was still on at the base of the charger after charging all night > (turns green when charged) and the little battery symbol on the display was > showing empty. > > The wall wart was putting out 10 Volts dc so that was OK. The spring > terminals that contact the battery in the base only had 5 Volts so it was > determined that the problem was in the charging stand. (5 Volts will not > charge an 8 Volt battery regardless of wishful thinking and hoping. --Duh!) > > Was it possible to dis-assemble the charging base? Yes! It required the > application of a #1 Phillips screwdriver to remove all four screws and > separate the bottom cover. And what did I observe then? Horrors!! Surface > Mount Device (SMD) components, part of the reason that I retired from the > repair industry. They are hard to see when your eyes get older. But it is > still possible to solder regular discrete components in their place if room > permits and there was plenty of room, so my hope endured. > > Noticing that there appeared to be some through-hole components I removed the > circuit board and looked at the other side. There were only three parts on > that side, a diode, an LED and an electrolytic capacitor. Looking more > closely I noticed that one leg of the diode was slightly greenish in color. > Upon touching the diode the leg crumbled from corrosion. Progress! > > Why would there be corrosion to the extent of crumbling the leg of a > component? It came from the electrolytic capacitor close by! And indeed the > capacitor was also corroding. > > To sum up this anecdote, after replacing the diode with a diode rectifier > from a junked out VCR power supply that also furnished a replacement > capacitor the base was re-assembled and full functionality was restored. > > The capacitor was a 10 microfarad at 25 Volts. > The diode was a 4001 so any regular diode would do. > The circuit board was well marked with polarity and identification on both > sides. > > Oh, by the way, of the three spring terminals that contact the battery the > center one is electrically unused. The charger will measure 8.02 Volts dc > when plugged in when measured at these terminals. > > Sorry for being so long-winded, but I wanted to furnish enough detail that > follow-up questions could be minimized. > > 73, > Forgetful John, KI5HOC > > > ________________________________________________ > Brazos Valley Amateur Radio Club > > BVARC mailing list > [email protected] > http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org
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