Stedy's RGB to SCART cable

Oh, and just one other thing I noticed the other day and would like to show you all.

I own a "big" Panasonic CRT TV and when I went through the owner's manual instructions, on the page relating to audio/video connections there is a warning note specifically stating "do not connect to this device a computer with a TTL output of 5V".

Now, is that a coincidence or what?

Sorry for picture quality and language but it translates to exactly what I have written above.








So, this seems to backup and reinforce the idea that care should be taken when making connections involving certain types of signal and amplitude on TV's.

Fortunately, I don't remember ever connecting the Amiga to this TV and hopefully will not try to find out what happens untill I take proper precautions by making a cable with the 330ohm resistor.

Originally Posted by Stedy

..., something I missed, is the DC offset of the Amiga video signal. Black level is about 600mV, it should be 0-50mV. This has an easy fix, on each of the RGB signals, add a 220uF capacitor, + end to the Amiga output. This will AC couple the video, with minimal droop...

Ian

Would this also apply to an Amiga 500?

[fpmpaolo]

Hello people, can I use a 150ohm instead of a 75ohm at pin 23 (SCART 16)?
"The BLANK signal (pin 16 of the SCART) is fed from +5V via a 75 ohm resistor, which together with the 75 ohm terminator in the TV, creates a voltage of 2.5V, adequate to RGB input mode."
Image says 47 to 270ohm acceptable range of values.
I couldn't find a 75ohm resistor at work.

[kinmami]

Originally Posted by fpmpaolo

Hello people, can I use a 150ohm instead of a 75ohm at pin 23 (SCART 16)?
"The BLANK signal (pin 16 of the SCART) is fed from +5V via a 75 ohm resistor, which together with the 75 ohm terminator in the TV, creates a voltage of 2.5V, adequate to RGB input mode."
Image says 47 to 270ohm acceptable range of values.
I couldn't find a 75ohm resistor at work.

hello using 150 ohm it will result in 1.67V, while using 220 ohm (which I do recommend) it will be 1.27V
200 ohm is more compatible with asian TV models/brands

[stevew]

Hi,

I bought an Amiga SCART cable from ebay, the cable works on my Panasonic G20 LCD TV from 2010 (although picture cropped on left slightly), and it works perfectly on my 21" Samsung LCD TV from 2017, no cropping and picture quality on both TV is excellent. Its made up of 9 cores + 1 ground wire, so the only ground wires connected are SCART pin 17 ---> Amiga pin 17 and SCART pin 18 ---> Amiga pin 19, and it has a 470ohm resistor on CYSNC (SCART pin 20) and a 180ohm resistor on BLANK (SCART pin 16)

I bought a 5m fully wired SCART to SCART and cut it in half, added a cut down db25 connector and the resistors as above. Plugged it into the Samsung LCD TV, works fine, no issues, great picture quality, plugged it into Panasonic and I get an issue with the picture jumps about every few seconds like it has not got a lock,sometimes when it jumps it flashes black.

I measured voltage with a mm, as my cable is 20 core with smaller wire gauge so resistance is slightly higher.

ebay cable measurements
CSYNC (470ohm resistor) - 0.484v
BLANK (180ohm resistor) - 1.430v

My cable
CSYNC (470ohm resistor) - 0.469v
BLANK (180ohm resistor) - 1.377v

Tried different resistors no difference on Panasonic
CSYNC (390ohm resistor) - 0.538v
BLANK (100ohm resistor) - 1.960v

I disconnected the 12v supply for SWITCH to see if that was causing interference, no difference on the Panasonic TV.

Wondering if anyone could assist here as to what the issue could be and what I should try next?

Thanks

[fpmpaolo]

Hello guys, I'd like to make a brand new scart cable using this PCB

https://www.pcbway.com/project/share..._EASY_PCB.html

Guide says I can use

270 to 510 ohm
1K to 4.7K ohm
47 to 270 ohm

resistors. Just in order not to do a bad work...can I use all the capacitors I find that suits that range? I don't know which ones I have at work but I mean...I ask it just to be sure.

[Supamax]

Originally Posted by fpmpaolo

Hello guys, I'd like to make a brand new scart cable using this PCB

https://www.pcbway.com/project/share..._EASY_PCB.html

Little OT: where do you see the prices on PCBWay?

[fpmpaolo]

Originally Posted by Supamax

Little OT: where do you see the prices on PCBWay?

You need to login and put the PCB on the basket. Anyway, I spent 12.88USD to get ten of them. Should you need one please DM me, I'll be happy to send one.

I found some capacitors. Picture says

1K to 4.7 ohm acceptable range of values
47 to 270 ohm acceptable range of values

I found a 1.8K and 100 ohm capacitors.
Can I use them?

[shaf]

You mean resistors and yes they should work.

[fpmpaolo]

Originally Posted by shaf

You mean resistors and yes they should work.

yes man I mean RESISTORS
Thanks.

[Supamax]

Originally Posted by fpmpaolo

You need to login and put the PCB on the basket.

Ok .
Are the shipping costs free worldwide?

Anyway, I spent 12.88USD to get ten of them. Should you need one please DM me, I'll be happy to send one.

Thanks for the offer .
Are they useful? The purpose is not 100% clear to me... do they facilitate the cabling/soldering?

[fpmpaolo]

Originally Posted by Supamax

Ok .
Are the shipping costs free worldwide?

As far as I remember no. Shipping costs are not free at all.
But the cheapest one from PCBWay to Italy is China post (or something similar). It took about 20 days or less from PCBWay to my house

Originally Posted by Supamax

Thanks for the offer .
Are they useful? The purpose is not 100% clear to me... do they facilitate the cabling/soldering?

they DO facilitate soldering! that's their main goal.

You solder the DB32 on the board, you solder the SCART cables on the same board. Then you solder the resistors on it. And you're done.
IMHO it's a more efficient and rock-solid way to make cables.
I bought THREE scart and 2 of them broke after a while.

I think I'll repair them with this.
But man...let the image speak! I think it's clearer than me

[Supamax]

Great!!