Today I Received...

[Derek_Stewart]

Hi,

One word of warning, when powering the Q68, please only use 5 volt 1 amp power supply, as anything more than 5v will damage the Q68 board.

I have repaired 3 boards already, maybe I should provide a suitable power supply or USB to 2.1mm dia connector.

[Pr0f]

it it too late to fit a polyfuse and sacrificial zenner ?

[Dave]

This is a design decision, and the only real area of concern is that the input 5V is passed directly to the keyboard and mouse. The internal 3v3 regulators can handle a bit more, but not dramatically so.

The problem arises when you have multiple power jacks, all aline, on the table, and you have to know which one is which.

I am hopeful a future revision might add a LM1117-5.0 or similar and specify a 9v input or similar. We can hope. It would be safer all round.

[dilwyn]

...a JS Technology Ltd Simple Video Scalar (QL version). Here are some pictures:
<snip>
I specifically asked for the QL version, and the Sales Receipt is marked "QL Firmware" and "Spec B", although I don't know what the differences (if any) are with the original version. Their website implies "Imporved (sic) picture sharpness. Added compatibility with a selection of input signal types."
It arrived quickly and well packaged. 2 day delivery! That package is too big for a standard letterbox. They send an email to let you know when it's being despatched, so you'll have a good idea of when to be home to take delivery.
They say it accepts PAL and NTSC inputs, and converts Composite, S-Video, RGB SCART, RGsB Sync-on-green or Component (YPbPr), converting to VGA PC type signal, with a single button to change video input modes. It deinterlaces the input signal of 480i and 576i, outputting progressive equivalent 480p and 576p. Note, VGA only output, no HDMI for example. Video input/output cables are not included with it, but the company say they can supply some types to order. I hope the ones I already have will be suitable. The audio output is two phonos - stereo audio directly passed from SCART input according to the little 4-page manual.
Won't have time to try it out until the weekend, but will report back on how it works and if it manages to upscale the full 512pixel/85 characters QL screen as it claims. Also, how it compares with the little unbranded SCART-HDMI upscaler I already have.
Price paid was £49.16+VAT tax, and £4.96+VAT for UPS courier shipping.
EDIT: Here's their website address: http://www.js-technology.com/store/prod ... product=56

OK, finally got round to playing with the Simple Video Scalar and guess what, I can't get it to work.

Using a QL 8 pin DIN-SCART cable for input, wired as below (purchased from Retro Computer Shack on eBay, not one I made myself) and which works fine when QL is plugged into SCART on two separate TVs apart from the usual loss of a couple of characters both edges, the simple video scalar does not seem to like the signal it's presented with. The button on the panel cycles through the following modes with the following results on a TV with SVGA socket and a monitor also with SVGA socket:
mode 1 - RGB SCART - no picture
mode 2 - RGB non-SCART or composite - no picture
mode 3 - RGsB/SoG sync on green - no picture
mode 4 - component - picture rolls wildly diagonally towards top right, colours correct
mode 5 - composite - also rolls diagonally but green-tinted picture
mode 6 - S-video - no picture.

On a second monitor, a 14 inch 1024x768 the monitor says "out of range" on all modes.

The VGA cable is a good quality purchased one which works fine with a PC.

Here's the SCART cable wiring to see if anyone can tell if any part of the wiring might have a bearing.

SCART ---- QL 8 pin DIN
7=blue wire (B) ---- QL pin 8 (B)
11=green wire (G) ---- QL pin 6 (G)
15=red wire (R) ---- QL pin 7 (R)
17=grey wire (CVBS GND) linked to pin 18 ---- QL pin 2 (GND)
18=grey wire (RGB status GND) ---- QL pin 2 (GND)
20=purple wire (COMP Video) ---- QL pin 4 (COMPOSITE SYNC)
16=orange wire (RGB status/fast blanking) ---- QL pin 1 (COMPOSITE VIDEO)

or pictorially:
[img]

scartql.jpg

[/img]

Hopefully, someone can interpret the results above to see if any wiring is amiss, even though the cable works fine for direct QL-SCART input.

Any ideas on what is happening to the picture and sync, before I contact JS Technology about it?

[tofro]

Dilwyn,

the two Composite lines (20-->4, 16-->1) of your SCART cable seem to be weird - Composite Video is connected to "RGB Status" [which is normally used to tell the TV that "RGB is valid"] and Composite sync is connected to the composite video signal - Maybe our TV didn't use these signals (some don't) and your scaler does. Can you re-check these lines, please?

Does the cable have any resistors in line? The QL outputs RGB-TTL, but SCART wants 0-1V analogue signals.

Tobias

[dilwyn]

Dilwyn,

the two Composite lines (20-->4, 16-->1) of your SCART cable seem to be weird - Composite Video is connected to "RGB Status" [which is normally used to tell the TV that "RGB is valid"] and Composite sync is connected to the composite video signal - Maybe our TV didn't use these signals (some don't) and your scaler does. Can you re-check these lines, please?

Does the cable have any resistors in line? The QL outputs RGB-TTL, but SCART wants 0-1V analogue signals.

Tobias

Thanks Tobias.
Will go back to check the wiring when I get time tomorrow.

I did think that the comp video/sync connection didn't look right, but as it was a purchased cable specially for QL and it works on everything else it's used with (including the HDMI upscaler, a TV and a SVGA monitor) I didn't pay any more attention to it. I mislabelled QL pin 5, that should have been VERTICAL SYNC. Pins 5 and 3 at QL end definitely not connected.

The cable does have resistors in the R, G,B, lines within the SCART plug. Inside heat shrinking so I can't see the values, will measure them with a multimeter when I get time tomorrow, and compare the wiring with published QL SCART cable details.
I used to have a second such lead which Tony Firshman made me years ago - can't find it to compare, sadly.

[Martin_Head]

In my note book I have a drawing of a SCART cable I made many years ago

QL-------------------- SCART

pin 2 ---------------- pins 5,9,13
pin 7 ---- 330R ---- pin 15
pin 6 ---- 330R ---- pin 11
pin 8 ---- 330R ---- pin 7

pin 4 ---- 330R ---- pin 16
pin 4 ---- 470R ---- pin 20

Yes, pin 4 is used twice.

[dilwyn]

Thanks Martin. That's six different wiring versions for a QL SCART cable I've seen now in all. SCART is a nightmare to get right.

Retro Computer Shack, whose cable I use with TV, are on holiday according to their eBay store, so I can't follow up with them.

I've sent a help request to JS Technology to see if they can either supply a cable or give me a definitive wiring that their Simple Video Scalar needs.

[dilwyn]

Although I might add that it looks like the wiring of the Retro Computer Shack QL-SCART cable is suspect, in that SCART pin 16 should go to QL pin 4 (Composite Synch) not QL pin 1 (composite PAL) according to most wirings I've seen, so when I get a chance a quick desoldering of the orange lead in the QL plug and join to the purple lead might help.

[fatbob_gb]

Retro Computer Shack only operate between Thursday 2pm and Sunday 5pm - the wiring for the QL Scart cable is shown here https://www.retrocomputershack.com/SCAR ... index.html