Enterprise Forever
:UK => Hardware => Topic started by: leonlas on 2020.December.07. 22:32:29
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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?
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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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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) :(
[attach=1]
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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.
[attach=1]
This one right resistor, Brown, Black, Brown, Gold:
[attach=2]
This is the not correct, Red, Red, Black, Brown:
[attach=3]
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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.
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The output from the modulator gives the "correct" signal ;-)
This means: RF signal make a stable picture?
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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.
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And, probably you have used this schematic:
(http://enterprise.iko.hu/cables/SCART.png)
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....)
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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.
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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...
[attach=1]
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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.
[attach=1]
[attach=2]
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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.
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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/
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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.
[attach=1]
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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.
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And that's it: an adapter! I made it without 19pin-20pin crossover and that's the effect. The first time I decided to do it on an adapter and my routine failed me. I forgot about the crossover. Before reading the rest of the posts, I decided to do without an adapter. IT LIVES! hahahahaha! The image is a bit bright but I will add a resistor and it will be ok.
I can see there is a really helpful community here - many thanks to YOU.
:smt041
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Don’t get mad, but I wouldn’t trust an adapter in this state.
Gflorez is right. Try it with a suitable cable.
(Attachment Link)
(Attachment Link)
Great plug 4 EP64! Do you make them yourself? Maybe you have to sell? I mean the plug itself without a cable and Scart.
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Great!
Your idea of an adapter for a Scart to Scart cable is brilliant, but for it you need to twist your mind... First time with the 90 degrees contacts( at the green PCB on your picture (https://enterpriseforever.com/hardware/problem-rgb-scart/?action=dlattach;attach=25943;image)), you can easily swap the rows. And then the second time with the cable, as the schematic is made for the female Scart connector at the TV side.
I would have made a lot of errors, sure.
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I wanted to make an adapter to use a standard SCART cable. It's a prototype in the photo. I need a housing and everything on one PCB. I was supposed to mill the plate but I have to think about it ...
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I'm glad that it works finally...
BTW it's a great idea to create an adapter instead of a cable, I do the same with all my retro RGB compatible computers/consoles (SMS, Amiga, Spectrum +2A, Videoton TVC & EP128). SCART is the final common way to compatible TVs, and proper size cables are still manufactured up to 5m.
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I don't think an adapter is a better idea than a direct cable for someone who only has an EP machine.
The adapter also requires a reliable EP plug first.
And more importantly, the direct cable has less of a contact fault option.
The adapter may be useful for those who connect multiple machines to the same TV.
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Yes, I think the same. Is for that I said that the adapter idea is brilliant... as an idea.
On the practice, direct connection is always the best.