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Author Topic: Problem RGB - SCART. (Read 46616 times)

Offline leonlas

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Problem RGB - SCART.
« on: 2020.December.07. 22:32:29 »
Hi.
 I'm new to the forum. I bought an E64 from egypt and started it. I changed the capacitors and measured the power, it is 5V and 12V.
I made a plug for RGB - scart for TV. Here's the problem: it can't catch sync. The image is in color but it floats diagonally to the side and up and down. The resistors are RGB and CSYNC. First I gave 100 ohms, then changed to 330 ohms. 12V is connected to pin 8 on SCART and from 8 to 16 a 470 ohm resistor. There is still a problem. I measured RGB multimeter and it's 0.2V CSYNC has 3V. I tried to lower the Volts on CSYNC with a potentiometer (resistor) but it does not change either. The same effect is present on two TVs. I also have a second E64 and there is the same trouble.
I don't know what to look for. Can someone help me - give me a hint?

Offline Dr.OG

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Re: Problem RGB - SCART.
« Reply #1 on: 2020.December.08. 05:33:00 »
Does the composite (monochrome) video work (A3)? You may use this instead of CSYNC (B5), connect it to SCART pin #20 without a resistor.
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Offline Judge

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Re: Problem RGB - SCART.
« Reply #2 on: 2020.December.08. 10:07:14 »
Try adjusting the L2 coil gently to the right or left with a plastic screwdriver.
Many types of TVs do not work normally with Enterprise.(experience) :(

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Offline Zozosoft

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Re: Problem RGB - SCART.
« Reply #3 on: 2020.December.08. 12:14:25 »
Check the value of R205. In one machine (also a EP64 from Egypt) found 22 Ohm instead of 100! :shock:
It is worked with a old 1980's CRTs, but not with a modern displays, because these somehow detect a wrong scart mode.
Replaced it to the right value then problem solved.

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This one right resistor, Brown, Black, Brown, Gold:
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This is the not correct, Red, Red, Black, Brown:
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Offline leonlas

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Re: Problem RGB - SCART.
« Reply #4 on: 2020.December.08. 14:59:31 »
I tried to connect A3 - no good change.
I tried to turn the coil - unfortunately it doesn't help either.
I checked the resistor - it's okey 100ohm.
I have 2 E64 units and both have the same problem.
The output from the modulator gives the "correct" signal ;-)   .

I connected the signal coming before the modulator, composite and the image is in colors and it does not jump but I want RGB and ...... ;-(

This is the effect of RGB as in the pictures below.
« Last Edit: 2020.December.08. 15:04:24 by leonlas »

Offline Zozosoft

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Re: Problem RGB - SCART.
« Reply #5 on: 2020.December.08. 16:12:44 »
The output from the modulator gives the "correct" signal ;-)
This means: RF signal make a stable picture?

Offline leonlas

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Re: Problem RGB - SCART.
« Reply #6 on: 2020.December.08. 16:36:18 »
You put it right: stable image. Yes.

And if SCART is connected, despite the bad picture, should there be sound? For example, beeping from the keyboard? Audible on tv -SCART.
« Last Edit: 2020.December.08. 16:39:24 by leonlas »

Offline gflorez

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Re: Problem RGB - SCART.
« Reply #7 on: 2020.December.08. 18:06:43 »
And, probably you have used this schematic:



Didn't you?

The sound output on the the RGB port is very weak, you only will hear it optimally with the Volume pumped up to the max, and it will add noise from the TV amplifier. Better take the sound from the Save Tape jack connector, It outputs in Stereo at the correct level!

The estrange and common on your set-up is that the two EP64s produce exactly the same issue WITH THE SAME CABLE, made by you.

Have you discarded a possible error on your cable?( I am the first here that sometimes overly trust on my experience....)
« Last Edit: 2020.December.08. 18:17:29 by gflorez »

Offline leonlas

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Re: Problem RGB - SCART.
« Reply #8 on: 2020.December.08. 18:33:19 »
I tried 2 different SCART - SCART cables.
Today I will connect to the third TV and maybe the LCD TV.
I connect through this adapter of my job:
I have 2 of these, one with resistors, the other without.

Offline Judge

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Re: Problem RGB - SCART.
« Reply #9 on: 2020.December.08. 18:33:57 »
The sound output on the the RGB port is very weak, you only will hear it optimally with the Volume pumped up to the max, and it will add noise from the TV amplifier. Better take the sound from the Save Tape jack connector, It outputs in Stereo at the correct level!

It looks like this...

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Offline Judge

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Re: Problem RGB - SCART.
« Reply #10 on: 2020.December.08. 18:51:38 »
I tried 2 different SCART - SCART cables.
Today I will connect to the third TV and maybe the LCD TV.
I connect through this adapter of my job:
I have 2 of these, one with resistors, the other without.

Don’t get mad, but I wouldn’t trust an adapter in this state.
Gflorez is right. Try it with a suitable cable.

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« Last Edit: 2020.December.08. 19:48:03 by Judge »
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Offline leonlas

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Re: Problem RGB - SCART.
« Reply #11 on: 2020.December.08. 19:16:58 »
He does not get nervous :-)
I did two and both would be bad .... maybe.
I have to solder directly to SCART and then it will be sure.
I've already made several dozen RGB cables for various 8/16 bit and they all work ;-)
But it must be the first time sometime.
I will check without this grommet, let me know.

Offline Dr.OG

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Re: Problem RGB - SCART.
« Reply #12 on: 2020.December.08. 19:45:56 »
In this case (using a converter instead of a cable) connect the csync signal to pin19 instead of pin20 of SCART socket. Pin 20 is csync IN, pin19 is csync OUT! See cable schematic here: https://www.leadsdirect.co.uk/technical-library/pinouts-wiring-diagrams/scart-wiring/
« Last Edit: 2020.December.08. 19:50:33 by Dr.OG »
ÉN ekelek, TE keregsz, Ő gyeleg,
MI ákolunk, TI vornyáztok, ŐK lendeznek.

Offline Judge

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Re: Problem RGB - SCART.
« Reply #13 on: 2020.December.08. 20:03:18 »
Connect the Scart cable to the adapter. Beep the connection between the EP connector and the Scart connector as shown below.
From this, you can find out if something is out of place.

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« Last Edit: 2020.December.08. 23:33:09 by Judge »
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Offline dangerman

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Re: Problem RGB - SCART.
« Reply #14 on: 2020.December.08. 22:35:26 »
In this case (using a converter instead of a cable) connect the csync signal to pin19 instead of pin20 of SCART socket. Pin 20 is csync IN, pin19 is csync OUT! See cable schematic here: https://www.leadsdirect.co.uk/technical-library/pinouts-wiring-diagrams/scart-wiring/

I agree with Dr.OG. You should connect cysnc to pin19. That is what you'll need to do if you're making a converter for a scart-to-scart cable. Likewise if you're using a converter you'll need to connect the audio to pins 1 and 3, not pins 2 and 6.