Monitor mode compatible overscan

[belg4rion67]

As promise I'll post some images from different scart-to-hdmi scaler buyed on amazon; it works fine with my LG LCD tv but doesn't work with a new LG smart tv

[dilwyn]

As promise I'll post some images from different scart-to-hdmi scaler buyed on amazon; it works fine with my LG LCD tv but doesn't work with a new LG smart tv

Scaler_box.jpg

Scaler_plug.jpg

Scaler_QL_screen.jpg

Thank you for the pictures. It looks pretty good. The screen dump shows you don't lose a couple of characters off the edges of the screen like a simple QL to SCART connection often does.

Shame it wouldn't work with the SMART TV. Maybe there's a good reason that just hasn't been found yet?

I couldn't find that exact upscaler you bought on Amazon, maybe it's Italy only, but searching for upscalers brings a choice of quite a few:

http://www.amazon.co.uk/s/ref=nb_sb_nos ... i+upscaler

They all look fairly similar, maybe based on same board or same chipset.

If anyone is tempted to get one which hasn't been mentioned here, be careful to check what connections they have. Some have composite (phono/RCA) connections only (may work with composite for the QL, but not sure what the quality would be like), some are for specific devices such as games machines, some for USB and so on. Some are described as "converters" so may not have upscaling to, ummm, upscale the Ql display. But there seems to be a good choice, from about 30 pounds upward. Here in the UK, there seems to be a few such devices from a trusted and well known supplier - Maplin, for example (I only took a quick glance, didn't check if Maplin's units were suitable!)

At long last we seem have found solutions to the QL versus monitors conundrum, it would seem

[ppe]

Hi everybody,

what kind of a SCART cable do you use with the upscaler unit?

Does it have inline resistors for the RGB signals and CSYNC? If so, what resistor values are you using?

I got my upscaler unit today and it does not show a picture at all with a SCART cable built according to the spec from Dilwyn's site http://www.dilwyn.me.uk/docs/hardware/scart.zip with 680 ohms on the RGB pins and 1.2k on CSYNC. This cable worked fine with an old TV of mine but I'm wondering if the resistor values are wrong for this upscaler box.

Cheers,
Petri

[dilwyn]

Hi Petri,

I use a lead I bought from a supplier on eBay. The resistors are covered in heat-shrink, so I can't read the colour bands off them, but they measure at 325 ohms with a multi-meter, all of them.

I tried an older lead Tony Firshman made for me a few years ago, that has 220 ohm resistors in it (red red brown banding is 221 ohm assuming I remember my colour codes right).

The Scart lead article shows how to calculate, so I guess you should be able to work back to find what difference to signal levels the reduced resistor values might make.

I hope, but not 100% certain, that SCART signal levels are common to all countries for this.

[ppe]

I tried an older lead Tony Firshman made for me a few years ago, that has 220 ohm resistors in it (red red brown banding is 220 ohm assuming I remember my colour codes right).

Hi Dilwyn,

thanks for the info! Does your older lead work?

I think I'll try replacing the 680 ohm resistors with lower value ones...

/Petri

[tofro]

Petri,
you R values also look a bit steep to me. About halfway would probably be closer to make me feel good
My cable has 220R, another one for the Spectrum 380 Ohms. Both work file with the upscaler.

Tobias

[dilwyn]

I tried an older lead Tony Firshman made for me a few years ago, that has 220 ohm resistors in it (red red brown banding is 220 ohm assuming I remember my colour codes right).

Hi Dilwyn,

thanks for the info! Does your older lead work?

I think I'll try replacing the 680 ohm resistors with lower value ones...

/Petri

Yes, both leads work fine. I normally use the one with the 330 ohms resistors, it has never given any problems with the upscaler. There is no discernible difference in picture quality with either lead.

[dilwyn]

This is a short message which was sent to me recently by John Moody, via my blog, on the subject of the upscaler devices. I hope someone finds it useful.

Hi Dilwyn,
Reference the above on the QL forum:-
Scart pin 16 is a switch for RGB/Composite, RGB= 1 to 5 volts
I connected a germanium diode + to pin 16 and orange wire (PAL) from the QL. This selects the RGB input. works with the HDMI unit from City Skys.
(Used a FDP40 from City Skys HDMI to VGA converter to connect to a VGA/DVI LCD monitor. Switch between PC & QL from the monitor!)

[ppe]

Well, this is rather interesting. I changed the resistors on the RGB signals to 220R but alas, no joy. Also, put a 680R on the CSYNC line and still no picture.

Googled a fair bit and found a lot of stuff on RGB-SCART cables on Amiga related sites. Learned that pin 16 on the SCART connector should be supplied with between 1V and 3V to force the receiving device to use RGB input instead of composite. In case someone is interested, it was this page: http://www.ianstedman.co.uk/Amiga/amiga ... scart.html.

To see if this makes a difference in my setup, as a test, I wired a 1,5V battery between pins 16 and 18 (18 is GND for 16). End result was a wonderful, bright and stable picture.

Now I'm trying to think of a clever way to supply the control voltage to pin 16. Amiga video connector has 5V and 12V output pins so it is trivial over there with a resistor but there are no output voltage pins on the QL video connector and I'm not very keen on leaving the battery hack in place

Does anyone have any ideas on how to create a more permanent solution for the control signal?

I guess one option would be to open up the upscaler box and see whether I could add a jumper wire somewhere to leech off a power rail to pin 16.

Cheers,
Petri

[1024MAK]

Try this cable arrangement:-

Code: Select all

Sinclair QL       SCART     Function
8 pin DIN       connector
    2 ------------- 17      0V Ground
    3 ------------- 16      QL=Comp PAL video, SCART=Blanking/RGB selection
    5 ------------- 20      QL=Composite Sync, SCART=Composite video or Sync
    6 ---[300 R]--- 15      RGB red video
    7 ---[300 R]--- 11      RGB green video
    8 ---[300 R]---  7      RGB blue video

This is how the SCART cable that I have is wired. It works fine with the HDMI converter shown earlier in this thread

Mark