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Spectrum +2 power supply replacement

withadwithad
edited September 2013 in Hardware
I bought my first Spectrum the other day, a grey +2, but it seems that the power supply is busted (I've tested it with a multimeter and tried replacing the fuse in the plug, with no success). I could just return it but it came with a decent bundle of games that I would also have to return so I'd rather get a replacement power supply.

From what I understand, the 9V 2.25A variation of this power supply should work, if I reverse the polarity so it's centre negative and assuming one of the connectors that it comes with fits. But I'll admit I don't understand a lot about power supplies so I wanted to check here first, in case I'm about to do something stupid and fry the hopefully-still-working rest of my Spectrum.

Also, if anyone else has tried finding a replacement +2 PSU and knows another good one, any suggestions would be much appreciated.
Post edited by withad on

Comments

  • DEATHDEATH
    edited September 2013
    yep, that'll work. As you say, its centre connection is negative, the barrel being positive. Set it up for 9 volts and you should be good to go (as they say in the USA).
    Oh bugger!<br>
  • 1024MAK1024MAK
    edited September 2013
    The 9V power supplies for ZX Spectrums are unregulated dc types. What does this mean? Well inside there is a transformer to reduce the mains voltage and to provide isolation. Then there are some diodes to convert the ac voltage to a dc voltage. And finally there is a large capacitor to smooth out the "blips" (caused by convering a sine wave to make dc).

    A disadvantage of this inexpensive design is that if there is no (or only a small) current drawn, the output voltage is a lot higher than if a load, that is to say the Spectrum is connected.

    The Spectrum will work fine with a input of between 8V and 10V dc (measured with a load, that is to say the Spectrum connected).

    The type you have linked to will work fine (as it is regulated).

    I'm just saying this, as you may want to look around before committing as prices vary.

    Mark
    Sinclair FAQ Wiki
    Repair Guides. Spanish Hardware site.
    WoS - can't download? Info here...
    former Meulie Spectrum Archive but no longer available :-(
    Spectranet: the TNFS directory thread

    ! Standby alert !
    “There are four lights!”
    Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb!
    Looking forward to summer in Somerset later in the year :)
  • withadwithad
    edited September 2013
    Thanks, guys. I picked up that power supply today and it works fine. Turns out the Spectrum is broken in at least a couple of other ways (faulty keyboard and cassette drive) but it's progress.
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