Date : Thu, 27 Feb 2003 19:50:17 -0000
From : "Barrie Ellis" <BarrieEllis@...>
Subject: Re: Master 128 on a TFT flat screen???
The following works for converting the B/W video output to colour (thanks to
the forgotten person who sent me this some years back):
Colour Video Output
On Master 128 issue 1 boards a 470 PicoFarad capacitor should be connected
between the east leg of R137 and the east leg of R153 which are located
directly to the east of the modulator. Connections should be made on the
component side of the PCB with the leads of the 470 PicoFarad capacitor
being soldered directly to the leads of the two resistors.
On Master 128 issue 2 boards link LK11 should be made
a Miniture Pin Jumper from http://www.maplin.co.uk (around 20p each, though
you may have to buy them in packs of 10).
Modifications for the BBC Model B and B+:
On Issue 1,2 & 3 boards a 470 PicoFarad capacitor should be fitted between
the emitter of Q9 (identified by an "e" next to one leg) and the base of Q7
(the central leg).
On Issue 4 and later, the cpacitor is on board and can be connected simply
by fitting link 39 which may be found next to the modulator in the far right
hand corner of the PCB.
On the BBC Model B+ link S26 should be made.
All this said - the picture output is not of a very good quality through
this method. Good luck!
www.OneSwitch.org.uk - under construction
----- Original Message -----
From: "Brian Widdas" <brian@...>
To: "Dawn and Austin" <dawnandoz@...>
Sent: Thursday, February 27, 2003 5:06 PM
Subject: Re: [BBC-Micro] Master 128 on a TFT flat screen???
> On Thu, 27 Feb 2003, Dawn and Austin wrote:
> > +SNIP
> > > >I'd have thought the biggest hurdle these days is finding a monitor
> > > >will scan as low as 50Hz/15.625kHz field and line rates,
> > >
> > > Technically, VGA/SVGA monitors are supposed to be able to deal with
> > low
> > > screen rates by default, as the old EGA text modes (that the PC BIOS
> > on
> > > startup) are rather low scan rates. However you may find newer
> > dont
> > > bother and presume the card will "emulate" the EGA, that is, generate
> > > output, but at a higher scan rate.
> > A solution to this would be to purchase an upscan convertor such as
> > sold for Playstation2 et al. They're manufactured by Redant and take a
> > composite video input
> The only problem with the BBC's composite video output (well, apart from
> the lower quality) is that it's only black and white.
> Fortunately, on the Master, there is a jumper somewhere near the video
> circuitry which will include the colour component (normally only fed to
> the RF modulator) in the composite video output.
> If you want to go down this route, the BBC Master Advanced User Guide has
> a list of all the jumpers. /Completely/ off the top of my head, I have a
> feeling it might be J39.
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