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What's gone well for you recently? No matter how big or small.

cstanton

I took a couple of weeks off work, as much as you can when it's in the middle of a lockdown pandemic in the united kingdom, and I had a couple of wins myself.

blown up chip

For many years I kept hold of a computer hard drive that had died on me, of all things the microcontroller on the control board blew itself up. I had looked for a replacement control board online and at the time they cost £100+ because this was such a common problem, however recently I looked again and found that it was on ebay for £6, with a 50/50 chance of being the wrong model.

 

image

 

I took a gamble. A direct swap of the board isn't what works with this, as you can even see highlighted in the ebay listing screenshot, each drive has a BIOS chip on it flashed with the necessary settings for the platters, sectors, etc. of the hard drive. Without the right BIOS chip, you'll just get garbled data or clicking.

 

Time for a bit of desoldering and kapton tape.

 

image

 

As luck would have it, it worked! My hard drive was brought back to life, and I was able to recover my data once more.

 

image

 

I'd say that is a good 'win' for £6 and a reflow station image

 

What's gone well for you recently?

Parents

  • Hi Christopher,

     

    Great job with the hard disk! What reflow station did you use incidentally?

     

    My mini-success today was fixing something too, in this case remotely fixing a car rear light via video chat.

    A friend sent across this photo, he was using a bench-top supply to test it, and only some LEDs were lit..

    image

    First thing was figuring out why he was measuring strange voltages with the multimeter - it turned out that he'd left the bench supply sense terminals disconnected for years! (He's not an electrical/electronics engineer and the power supply was a hand-me-down with no instructions) so the control loop was not happy...

    image

    Anyway long story short, it was an interesting fault.. I'll leave a gap in case anyone wants to try to figure it out.. answer below.

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

    Looking at the solder-side of the PCB, it was clear that the LEDs which were lit, were in chains of three and a resistor. There were three sets in parallel, for a total of nine lit LEDs.

    R1---LED1---LED2---LED3

    R2---LED4---LED5---LED6

    R3---LED7---LED8---LED9

     

    R1, R2 and R3 are the darker smokier resistors.

    However, the unlit LEDs were in chains of four, i.e.

    R4---LED10---LED11---LED12---LED13

    and so on.

     

    There is also a single diode on the PCB to which all the parallel chains are attached. Anyway, it turned out that there was about 5.5V across the diode.. meaning it was in a weird enough damaged state that there wasn't enough voltage to make the chains of four LEDs be able to be lit, if the PSU was set to (say) 12V. Replacing the diode fixed it of course.

Reply

  • Hi Christopher,

     

    Great job with the hard disk! What reflow station did you use incidentally?

     

    My mini-success today was fixing something too, in this case remotely fixing a car rear light via video chat.

    A friend sent across this photo, he was using a bench-top supply to test it, and only some LEDs were lit..

    image

    First thing was figuring out why he was measuring strange voltages with the multimeter - it turned out that he'd left the bench supply sense terminals disconnected for years! (He's not an electrical/electronics engineer and the power supply was a hand-me-down with no instructions) so the control loop was not happy...

    image

    Anyway long story short, it was an interesting fault.. I'll leave a gap in case anyone wants to try to figure it out.. answer below.

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

    Looking at the solder-side of the PCB, it was clear that the LEDs which were lit, were in chains of three and a resistor. There were three sets in parallel, for a total of nine lit LEDs.

    R1---LED1---LED2---LED3

    R2---LED4---LED5---LED6

    R3---LED7---LED8---LED9

     

    R1, R2 and R3 are the darker smokier resistors.

    However, the unlit LEDs were in chains of four, i.e.

    R4---LED10---LED11---LED12---LED13

    and so on.

     

    There is also a single diode on the PCB to which all the parallel chains are attached. Anyway, it turned out that there was about 5.5V across the diode.. meaning it was in a weird enough damaged state that there wasn't enough voltage to make the chains of four LEDs be able to be lit, if the PSU was set to (say) 12V. Replacing the diode fixed it of course.

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