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Mild corrosion on a circuit board

Discussion in 'Electrics UK' started by phatboy, 16 Oct 2020.

  1. Gasguru

    Gasguru

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    Just be aware that some components (eg. relays) are available with different sealing specs...so assuming you can wash the pcb could be a big mistake.
     
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  3. Harry Bloomfield

    Harry Bloomfield

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    They charge as much as they can get away with charging for them. The purchaser is over a barrel, they either buy it, or fit a new boiler, unless they can find a company which offers refurbed/repaired ones cheaper.
     
  4. winston1

    winston1

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    Several years ago I had a plumber declare a PCB was faulty in a boiler and he demonstrated how pushing it made the boiler try to start. Replacement quoted at over £100 plus labour. Sent him on his way saying I would think about it. Once he had gone I got the PCB out and inspected it. Several dry joints mainly on the pins on the connecting cables. Five minutes with a soldering iron and all was well. Spoke to the plumber later and told what I had done and said I would pay him he call out charge if he popped round. He did not seem impressed saying he had never heard of anyone repairing a PCB and that it would not last. He did collect his call out fee but left me in no doubt not to call him again as it was not worth his while. Sour grapes I suppose. The PCB lasted several more years until the boiler was changed for other reasons.
     
  5. mattylad

    mattylad

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    I have always repaired my own boiler PCB's, 2 boilers back the WB one would often burn out a relay so I had to add suppression on the contacts, also rewound the fan twice because the numpties that fitted it didnt account for the phenomenon known as horizontal rain :)
     
  6. Keithmac

    Keithmac

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    I repaired a Honda CBF1000 a while back, Throttle Position Sensor was faulty (a £50 part at best).

    They didn't sell it separate from the Throttle Body assy and a new one was £1100+ vat iirc. Bloody rip-off.

    You could by a Honda car TPS for £30 on it's own (wouldn't work on the bike unfortunately).
     
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  8. Harry Bloomfield

    Harry Bloomfield

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    Rewound, that is going some :)

    Our original boiler was an ancient Gloworm, pilot light, piezo ignition and with the occasional part - I kept it going for decades, until the condensing era and still working fine when replaced. The replacement condensing boiler gave constant problems, three circuit boards and low temperature fan wiring run behind the boiler melting.

    The PCB failures were a known issue with the transformer burning out, but the no one ever mentioned problems with the inadequate temperature fan wiring burning and shorting, wrecking the PCB. After the second PCB failure, I managed to eventually source a replacement transformer to get one of the boards working, as a back up to the third one fitted. When the third one failed, I just swapped in my repaired one, but that failed to work. Investigating further, I found the fan wiring had wrecked the PCB's. At that, I gave up and ordered a new Vaillant boiler installation, which has so been 100% reliable.

    I tend to keep a few spares around to meet the common failure points of my heating system, rather than having to make distress purchases. Our original 3-port failing was the most regular failure, so I always had two ready to fit spares in the cupboard, either new or ones I had refurbed. When Vaillant was fitted, I decided to change the 3-port for a MOMO valve from a spring return model, assuming less stressed/ longer more reliable life. I only keep one spare actuator for that :)
     
  9. Harry Bloomfield

    Harry Bloomfield

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    A lot of these things are built from perfectly standard parts, it is very expensive to get custom components made. It is common for assemblers to deliberately scrub part numbers from components, to defeat anyone trying to repair a sub-assembly.
     
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  10. mattylad

    mattylad

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    The flu was slightly upwards as it went out the side wall, being an end terrace - when it rained the wind blew it back down the flu and straight onto the top of the fan which caused the windings to go bang.
    Given that a new fan was £80+ and we had coil winding machines at work it was not really hard to rewind.
    Preventing the rain coming in, now that was harder. :)
     
  11. Harry Bloomfield

    Harry Bloomfield

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    I actually bought a brand new fan for my boiler, because it had reported a fan failure, before destroying the PCB's. There was nothing at all wrong with the fan, what wasn't obvious was the melted and shorted wiring leading the fan. So I now have two perfectly good fans in stock, but unfortunately not for my present boiler :(
     
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