Ah Ha I know this mod, search the web for this tinker on a Spectrum or ZX Spectrum it should be found easily enough (I can't do it during the day as BB is watching). If I remember rightly the at the end of the article/item it suggest that the same mod could be done on a QL or any computer with this same modulator. From memory I think a decoupling capactior was used (there may be a couple of resistors in there to correct voltage levels i.e. PD, but I may be mixing that up with the SCART adaptation).
Hope this helps, Lee On Wed, Aug 31, 2011 at 7:02 PM, Dave Park <[email protected]> wrote: > On Wed, Aug 31, 2011 at 12:32 PM, Dilwyn Jones > <[email protected]> wrote: > > Dave Park wrote: > >> > >> I have heard there is a simple "colour composite video mod" but after > >> extensive googling I have not found it. Does anyone have details of > >> this mod, to get me through until I can locate a working old school > >> TTL RGB monitor? > >> > >> I have restarted work on a couple of games I was writing before the > >> heatwave and drought made it too pleasant to be outside ;) > > > > There are a couple of articles by Richard Cooke, Marcel Flipse and Bob > > Gilder on my website at http://www.dilwyn.me.uk/docs/hardware/index.html > > which show various calculations required for video mods for various types > of > > monitor. > > > > Does your TV have a RGB SCART input? Richard Cook's article might help to > > work out making > > > > Have a look at this too (again a suggestion from > > Lee): > http://www.fruitcake.plus.com/Sinclair/Spectrum128/SCARTCable/Spectrum128SCARTCableQL.htm > > > > There is also a British company JS Technology who do a little RGB to TTL > > video converter which has been tweaked for QL overscan etc. Lee Privett > has > > one of their little video scalar boxes and there is an article about it > in > > Quanta magazine June/July 2011 issue. See their website > > http://www.js-technology.com/store/category.php?id_category=5 > > > > Hope something there helps... :-) > > > > Dilwyn Jones > > Alas, I am in the US and have a US QL. There is no such thing as SCART > over here. > > I read that the composite mod is simply disconnecting power to the > modulator and connecting the composite input to the center pin of the > output. This will work well for mode 8, but not so well for mode 4 due > to color timings. In a US QL it would also be very noisy due t the QL > ground being so noisy. Also, I'm not sure I will be able to see all > the screen area. > > I think I am destined to buy the RGB->VGA converter board for $39.95 > as one of the programs I am writing does not fit well with mode 8. > > Oh well, back to building my home-made floppy enclosure... > > Dave > _______________________________________________ > QL-Users Mailing List > http://www.q-v-d.demon.co.uk/smsqe.htm > _______________________________________________ QL-Users Mailing List http://www.q-v-d.demon.co.uk/smsqe.htm
