Tony Firshman wrote:
> > On Wed, 10 Jul 2002 at 11:01:02, Alan Tyson wrote: > (ref: <001101c227f9$107a84c0$fb30883e@alantyso>) > >> >>> This can be dangerous, not only to him, but to the monitor >> >> & QL - he could >> >>> end up frying either or both of them. >>> >> Thanks for the warning. He's pretty clued up as an Elec.Eng. >> lecturer by trade, and his house has had live TV & radio >> chassis lying around more time than not over the years. Stupid question (ie it's been ages since I played with these things): As the QL uses TTL levels for display (RGB) output, could a set of buffer chips be put between the output pins (of the DIN socket) of the QL and the input to the monitor. Thus, if a wrong connection was made, these buffer chips would get fried in preference to the QL output? <snip> >>> However, there appears to [possibly] be a mistake in the >> manual, as the pin >>> functions were given in 'QL world' (May 1987) differently: >> >> Is it possible the QL World version came from "p31 of the >> Concepts section of the QL User guide"? The 15MB QL Service >> Manual says in para 1.1 of page A1 under "monitor >> connections" that its version replaces those in the User >> Guide. Having just read them in parallel (Appendix A of service manual 1.2-1.5, pages A1/A2, and QL Manual Concepts page 33 [tho']), they are identical. >> >> Anyone care to hazard a guess as to which is right? Anyway, >> pin 5 won't have a signal if QL World is right. > > QL Manual 12/84 concepts is the right one - which I assume was the one > quoted from QLW (snipped). My QL manual concepts section (12/84 - Pg 33) has: 1 - PAL 3 - VIDEO 4 - CSYNC 5 - VSYNC My QL World May 87, Pg 25 has: 1 - VIDEO 3 - PAL 4 - CSYNC 5 - N/C My QL Service Manual has on the Circuit Diagram (both Issue 5 & 6): 1 - VIDEO 3 - PAL 4 - VSYNCH 5 - CSYNCL and in Appendix A: 1 - PAL 3 - VIDEO 4 - CSYNC 5 - VSYNC And from what I remember (when I hacked my B/W Phillips TX TV to have a monitor [composite video] input) in testing the outputs of the QL with an oscilloscope - displaying the vertical bar test card: MODE 8 OPEN#3,SCR512x256a0x0 FOR i=0 to 7:PAPER#3,I:PAN#3,-32 I think QLW has it right: 1 - VIDEO, 3 - PAL (ie the colour modulation occurs on Pin 3). > The circuit diagram (in the downloaded service manual) got it worng (but > is also not very legible)! > > I have corrected circuit diagrams (correcting a few other errors too) if > needed. What are the corrections - can u let me know please?
