What electronics or electrical did you do today?

Discussion in 'Electronics & Electrics' started by /invariance\, Jun 9, 2019.

  1. /invariance\

    /invariance\ Member

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    Today I replaced the caps in a 3Com switch
    138FBB86-2DBA-4BB3-AA85-561076966ED9.jpeg
    The bottom of the caps had all pushed out too. It’s a wonder none had popped.
     
  2. gdjacobs

    gdjacobs Member

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    KZE or KZG series?
     
  3. _zak

    _zak Member

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    I've spent the last couple of days converting my microscope light from 240 V AC to 12 V DC. It was working fine, but I didn't trust the build quality - the microscope is great, but the light was definitely built to a price.

    Circuit is based on a 555 timer (I used this DIYODE article). I'm pretty happy with the result, particularly given it fits back in the original housing (after some 'mods' performed with side cutters and a craft knife).

    Light.jpg
     
    Last edited: Jun 11, 2019
  4. OP
    OP
    /invariance\

    /invariance\ Member

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    KZG.
    Didn’t even consider that when replacing them, but probably anything would be a marked improvement on what was in there.

    Nice conversion.
     
  5. dakiller

    dakiller (Oscillating & Impeding)

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    Not exactly today, but the latest thing I’ve been doing at home is this little board to build a POE based light switch controller

    97FB2C1B-B208-4CBD-B180-4CF3794C5E92.jpeg F1BEBF3E-6334-4139-BF3F-A3F29B9824F1.jpeg AA2B2573-4A17-499D-A39D-A8452F3C366A.jpeg 52CCB457-3C94-4C45-A1ED-2C1DBA87485E.jpeg 9011E764-C3F4-4DA6-B5D4-2823AE8719F1.jpeg
     
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  6. goldpenis

    goldpenis Member

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  7. dakiller

    dakiller (Oscillating & Impeding)

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    They aren’t pcb mount, I just put large holes for the lugs to fit. They’re RGB too :)

    U7 is for better routing out of the BGA. It is all very tight even with 4 layers
     
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  8. dirtyd

    dirtyd Member

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    Surface mount RJ45 feel OK physically? I am a bit wary of SMD for connectors like that. Guess it'll be set and forget though?

    Also love the "oops forgot those resistors" mod on J2 :lol:
     
  9. dakiller

    dakiller (Oscillating & Impeding)

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    Second last picture, shows the large tabs securing it down as well. Micro USB's on just about every product are held down with less

    Leaving the resistors off wasn't the biggest oops either, see C29 and the via that I managed to put in that shorted the 3.3v and GND planes together. It is rare to prototype a PCB and not forget something or mess something up
     
  10. dirtyd

    dirtyd Member

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    Yeah I noticed those tabs just after I posted. I've used hybrid Micro USBs that are SMD pins with a couple of through hole posts, they feel pretty solid.

    I know what you're saying about rev 1 PCBs - last board I made had an RTC, first RTC I picked had integrated load caps for the crystal circuit. Then I decided the RTC needed alarms, changed RTC. New RTC requires external load caps, forgot to add them... surprise surprise, crystal no worky! DRC can't catch stupid shit like that :lol:
     
  11. OP
    OP
    /invariance\

    /invariance\ Member

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    Desk fan I use to move the air around my pc's under the desk virtually seized up. Pulled it down, cleaned the bushes and re-greased everything and she's off and running. :thumbup:
    (More of a mechanical repair, but it is an electrical appliance :))
     
  12. Radley

    Radley Member

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    Nothing. I've had one of my electric guitars on the bench for 2 months now because I can't figure out how to get solder to stick to the back of the pots.....
     
  13. OP
    OP
    /invariance\

    /invariance\ Member

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    Sandpaper and Bakers soldering paste is my weapon of choice.
     
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  14. goldpenis

    goldpenis Member

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    Have I got an electronics repair 'win' for you!

    I purchased a rowing machine to assist with aerobic conditioning and to complement my BJJ training. After looking around for ages for a nice unit that wasn't going to cost me the world, I settled on an Infiniti r100apm machine; a commercial rower with a myriad of features. The catch was it was being sold as not working/faulty due to missing its plug pack at a price of $250 (I think retail was around $1800 when new and the sell for $1000+ second hand). The seller claimed it should work with a new supply but mentioned 'sold as is, assume it faulty'. With a desire to get fitter, having to contend with a disgruntled wife for having a commercial rower in the house and picking up the unit from a very dodgy looking deli, the rower became mine!

    I commenced investigation into the supply and found a comparable unit from the technical specifications in the manual in my box of spares! Upon powering in the unit, there was not one sign of life! DC output was ok from my spare supply and I was able to trace power through the rowers electrical harness to the computer, do I knew it was getting power but the computer remained dead. Upon opening the computer, I found two totally destroyed TO92 devices, with some PCB damage and charring. They were so badly burnt/destroyed I was unable to identify any markings/values on the parts, and initially conceded a totally new PCB would be required unless I could obtain a schematic or do some reverse engineering. Google offered no help so I attempted to seek information from the supplier.

    The supplier offered no help and had no concern for my struggles, insistent a new PCB was required to be purchased from them at the cost of $360. I was obviously reluctant, as I was somewhat sure I could resurrect the existing computer having the part number identifiers. I asked for a schematic (not a chance) or even just a picture of a new computer PCB that might identify part numbers on the devices, but was offered no remaining assistance. Frustrated, I returned to the office for further investigation.

    Upon looking at one of the devices, I was able to just make out some markings thanks to a monocle, some IPA on a cotton bud and a bright light. Google helped me identify it as a 5vdc regulator, which was a small win! I still had no idea of the other device as the case was blown apart and missing. With further curiosity, I was able to identify the last letters on the case of what was left of the destroyed device and upon comparison with the now identified part (5vdc regulator), they matched!

    With nothing to lose, I headed to Jaycar and shelled out $1.60 for some replacement parts. A quick change over, PCB clean and reassemble, I held my breath, applied power and was met with an audible ''beep" and working computer!

    What a win! I was a little shocked the PCB has two individual 5vdc regulators being powered of the same input. Felt like a needed to put this up in the event some other poor bugger is faced with a whole computer replacement only option!

    I'll put up some pictures later and the part number information.
     
    Last edited: Sep 1, 2019

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