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  1. Replies
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    It was all about antennas, well visible ones that...

    It was all about antennas, well visible ones that is. Explains why the old house I bought in Sydney some decades ago had the TV antenna set up in the ceiling cavity under the tile roof :)

    Now I'm...
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    This was sudden - wasn't he spruicking for Labor...

    This was sudden - wasn't he spruicking for Labor just the other day?

    RIP Bob
    The nation will remember you above many others
  3. And with all that we were upstaged by a kiwi...

    And with all that we were upstaged by a kiwi Richard Pearse who flew a powered aircraft of his own design and construction (in NZ) some 9 months prior to the Wright Bros first flight....
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    You can weld Al with MIG DCEP and Argon but I...

    You can weld Al with MIG DCEP and Argon but I found it a really messy weld. What you need for Al is AC TIG with balance adjustment and maybe even variable frequency as well which makes the machine...
  5. The first challenge will be removing a FET...

    The first challenge will be removing a FET without damaging the PCB and adjacent components, could take more than a bigger soldering iron to do that. Something like a hot air rework station so you...
  6. Impressive unit going by the video linked above...

    Impressive unit going by the video linked above
    Are all the fets destroyed to the extent that no numbers can be read on them? - seems there'll be quite a lot of them
    Also are they all N-channel?...
  7. With a basic idea of the required minimum ratings...

    With a basic idea of the required minimum ratings (voltage, current, on resistance) a bit of browsing at Element14 should turn up a list of candidates in the right package (TO220 or TO247 etc). Does...
  8. You can make a pretty good guess as long as you...

    You can make a pretty good guess as long as you know what voltage they're switching IE if the fet(s) are switching rectified mains 240V RMS the peak voltage will be around 315V DC so you need at...
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    Better check that the motor doesn't have a...

    Better check that the motor doesn't have a problem like a tight bearing, impeller jammed with sucked in junk etc causing it to take excessive current.

    That R008 resistor looks like a 1W rating...
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    One of those things that might be useful some day...

    One of those things that might be useful some day has actually served its purpose :)
    Circuit looks extremely similar so shouldn't be a problem to wire it in even if only temporarily for testing
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    RSE2 looks like a current sensing resistor to me...

    RSE2 looks like a current sensing resistor to me IE 0.008ohm for the controller to monitor the load current and it could cause problems if it's gone high in value. I'd be looking for a datasheet for...
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    Looks like Q1,2,3,4 are mosfets connecting P+ and...

    Looks like Q1,2,3,4 are mosfets connecting P+ and B+ controlled by U5 which stop charging when the battery voltage hits the threshold. B1,2 3 are for balancing the cell voltages. If the overall...
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    That 2 year warranty on the original battery...

    That 2 year warranty on the original battery supplied by NBN lines up nicely with my first alarm which came up precisely to the day 2 years from initial start-up. That original install provided a...
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    FTTP NTD box backup battery

    Had the 'replace battery' alarm some time back so I dutifully charged out and got ripped off IMHO for a replacement 12V SLA battery which fixed the alarm problem (wasn't really a big deal). Did some...
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    Finally fixed and passed multiple tests today....

    Finally fixed and passed multiple tests today.
    End result about $20 parts, $1000+ labour lol but as a one-off educational thing that's acceptable.
    If there was a dozen of them broken down they'd be...
  16. The primary is the 'flimsyest' winding so I'd go...

    The primary is the 'flimsyest' winding so I'd go for an open circuit there being more likely than the secondary but an ohmmeter will prove which side is the culprit. As it's a 6VA rated transformer...
  17. Those appliances must be deriving their 'clock'...

    Those appliances must be deriving their 'clock' signal from the mains frequency and the 50Hz from the inverter is just a whisker fast like 50.01Hz is enough to gain a minute every 3 days. Assuming...
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    Success at last - charged a battery with it after...

    Success at last - charged a battery with it after fitting in a new PWM controller chip (UC3845)
    It did inexplicably blow the fuse early in the testing procedure but no other damage found so I put it...
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    From my years in the education system, an English...

    From my years in the education system, an English billion was a million million as you say but the American billion was 1000 million and I always assumed that was to make it easier to claim yourself...
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    In for a penny, in for a pound (must be old age...

    In for a penny, in for a pound (must be old age :) )
    Found 3 faults on the PWM board IE UC3845 chip, 1N4148 shorted and a 1k resistor open cct so not giving up just yet and should have a replacement...
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    Can't put a price on fun :)

    Can't put a price on fun :)
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    Definitely spoke a little too soon on this one as...

    Definitely spoke a little too soon on this one as it was going through the motions OK like detecting the battery, state of charge, voltage etc but nothing was happening at the output when charge...
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    Fully functional now (as far as I can tell...

    Fully functional now (as far as I can tell anyway)
    Has a tougher FET now and improved the heatsinking with a bit of thermal paste

    https://i266.photobucket.com/albums/ii243/pilgrum5/BattChrgr.jpg...
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    Compared to some my gadgets, that's a work of art...

    Compared to some my gadgets, that's a work of art :)
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    I had this problem some years ago when driving a...

    I had this problem some years ago when driving a largeish stepper motor from a PIC based circuit IE hit the motor with too high a stepping rate from standstill and it just quivered going nowhere....
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