Posts Tagged Repairs
Separately charging all four cells from the Baofeng BL-5 packs covered the Electronics Bench with wires:
The cell sits on a ceramic tile as a nod to fire safety, although I doubt it makes any difference.
The discharge tests showed two nearly identical pairs:
Surprisingly, cells A and B (upper traces) were deaders in the original packs. Cells C and D (lower traces) were more-or-less fully charged, but now have a lower terminal voltage and slightly lower capacity. I have no explanation for that, nor for the voltage undulations.
The rebuilt packs pair up A+B and C+D.
Reassembling pairs into the pack shell and resoldering all the leads produces a good pack:
I later added a snippet of heavy manila paper under the nickel tape bent around the edge of the pack as a third level of insulation, in the interest of having the nickel tape not produce a dead short between the isolated – terminal and the + cell case.
Memo to Self: tape the long wiggly leads from the protection PCB to the radio contacts (at the left side) before soldering the PCB to the cell terminals, because an inadvertent short will convert the 8205A battery protection IC into a Light-Emitting IC, at least for a moment, and subsequently release the Acrid Smell of Electrical Death. A handful of charge PCBs are en route halfway around the planet, from which I intend to liberate one IC for this board; with luck, I didn’t incinerate anything else.
The pack works fine in the radio, as does the APRS interface:
Unfortunately, two APRS iGates vanished in the last year, leaving poor coverage south of Poughkeepsie.
Not much to my surprise, both Baofeng BL-5 lithium batteries went bad on the shelf:
The longer traces show their original capacity, back in the day.
Whacking a chisel into the obvious split lines broke the solvent glue bonds holding the case sections together, after which some slow prying defeated the double sticky foam tape on the cells:
A closer look at the (dis)charge controller PCB:
The other side of the PCB has no components, so what you see is what you get. The larger IC proclaims FS8205A EP050C, which may indicate a vague relation to an S8205 protection IC. The datasheet shows a 16 pin TSSOP package containing an IC for four or five cell batteries, completely unlike the 8 pin package on the PCB, but when you buy enough of anything, you can get anything you want.
In common with all cheap lithium batteries around here, the “thermistor” terminal connects to a 10 kΩ SMD resistor steadfastly maintaining its resistance in the face of all temperature variations.
Some probing shows one feeble cell in each pack. Perhaps a Frankenbattery built from the debris will have enough capacity for a standard ride around the block.
The TinyTrak3 on the Wouxun adapter wasn’t working, showing a dim red Power LED to indicate it wasn’t getting enough juice. A bit of tracing showed my adapter board provided just over 5 V to the poor thing, not the nearly 9 V it should be getting, which led me to believe the transistor switching the supply had failed. A bit more tracing, however, revealed the true problem:
The schmutz on the black cap matches up with a crater in the rear of the (originally not so) brown cap.
The Little Box o’ SMD Caps revealed two nearly identical sets of 33 μF caps, one with a 6 V rating, the other with 16 V rating. Yup, when I added that cap in the hopes of reducing RFI troubles, I soldered the wrong one onto the PCB: it’s my fault!
The poor thing lasted for over six years with just under 9 V applied to it, so I can’t complain.
I removed the corpse and reassembled the box without the additional cap (and without the terminals contacting the back of the Wouxun, because reasons). If RFI turns out to be a problem, I’ll take another look at the situation.
My carefully contrived plug plates for Wouxun radios:
… of course don’t fit the Baofeng radio. This being in the nature of a final fix, I chopped off enough protrusions to make the remainder fit snugly into the recess.
The case containing the TinyTrak3 GPS board and the APRS-voice adapter PCB of course doesn’t fit in place of the Baofeng battery pack, so I replaced the battery contact studs with simple 4-40 screws to prevent heartache & confusion.
Based on one ride, both Baofeng batteries have very little capacity left after several years on the shelf, which comes as absolutely no surprise whatsoever.
I call it between 7 and 15 gpg. Based on the feel of the water just before regeneration, I’d been guesstimating 15 gpg, so it’s within reason.
I’ll back the softener off to 10 gpg and see what happens.
Because the OLED driver came from the
pip package manager, not the Raspberry Pi’s system-level
apt package manager, it (or they, there’s plenty of code under the hood) don’t get updated whenever I do system maintenance. The doc says this should do the trick:
sudo -H pip install --upgrade luma.oled
However, it turns out the new version has a slightly longer list of pre-requisite packages, causing the update to go toes-up at a missing package:
Could not import setuptools which is required to install from a source distribution. Please install setuptools.
So update (or install, for the new ones) the missing pieces:
sudo apt-get install python-dev python-pip libfreetype6-dev libjpeg-dev build-essential
Doing so produced a backwards-compatibility error in my Python code:
... change ... from luma.core.serial import spi ... into ... from luma.core.interface.serial import spi
The motivation for all this fuffing and fawing came from watching some OLEDs wake up completely blank or become garbled in one way or another. Evidently, my slower-speed SPI tweak didn’t quite solve the problem, although it did reduce the frequency of failures. I have decided, as a matter of principle, to not embrace the garble.
Soooo, let’s see how shaking all the dice affects the situation.
After a year of fairly light use, the lens holder (and “attack ring”) of my J5-V2 flashlight worked loose and began to rattle. The ring holding the lens in place turned out to be finger-loose, but that wasn’t the entire problem, so I removed it and looked inside:
The mysterious alien egg resides on the upper-right side of the LED emitter.
The aluminum ring holding the LED assembly in place was also finger-loose, so I unwound it to take the whole front end apart:
Reassembly with a few dabs of Loctite in appropriate places should prevent future rattles.