+2a Video fix funny... - Sinclair

This is a discussion on +2a Video fix funny... - Sinclair ; Lads, I was hoping to build a spectrum +2a into an old laptop case (Cant let those comie 64 boys have one and not us eh!), anyway, Ive hacked the case to bits and cut the +2a board a bit ...

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Thread: +2a Video fix funny...

  1. +2a Video fix funny...

    Lads,

    I was hoping to build a spectrum +2a into an old laptop case (Cant let
    those comie 64 boys have one and not us eh!), anyway, Ive hacked the
    case to bits and cut the +2a board a bit to fit (Bye bye printer
    interface). So far so good.

    I have 2 x 5 inch LCD displays - one on old thing I picked up and also
    a competition pro PSONE screen - both of which take a composite input.

    Thing is, I have built the +2a 3 diode video interface from sami's
    site at

    http://user.tninet.se/~vjz762w/fixuspec.html

    and it works great - on a tv with a SCART interface! Not on my LCD
    screens mind you! The PSONE one shows a smeary black and white image -
    the other gives a picture, even with colour sometimes but also lines
    on it... back to the drawing board on that....

    Anyway,on the 3 doide circuit I am using a bc547b and built direct on
    the board just as in sami's photos and what I noticed was, if I
    disconnect the collector from the +12volt line (I was trying 5volts
    instead and also because the trany got a bit warm!) and leave it
    disconnected - I still get a good picture!

    Can anyone explain why it still works??

    Dicky

  2. Re: +2a Video fix funny...

    On 2 ene, 23:37, dickydodds wrote:
    >
    > Can anyone explain why it still works??
    >


    The circuit must be draining current from elsewhere. I'll give a look
    when I have a little time and tell you something.

    I did once succedded in connecting a Spectrum plus to an LCD
    canibalized from a PPC1512, but I don't know if that would serve to
    you...

  3. Re: +2a Video fix funny...


    Thanks for that. As for the LCD, its got to be a colour one! I am
    going to try an ordinary 48k next but I wanted the sound and 128K
    really, but its not really a problem.

    Cheers,

    Dicky


    On Jan 4, 11:09 am, lucamar wrote:
    > On 2 ene, 23:37, dickydodds wrote:
    >
    >
    >
    > > Can anyone explain why it still works??

    >
    > The circuit must be draining current from elsewhere. I'll give a look
    > when I have a little time and tell you something.
    >
    > I did once succedded in connecting a Spectrum plus to an LCD
    > canibalized from a PPC1512, but I don't know if that would serve to
    > you...



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