Ferguson MA20 via SCART to modern TV

ikci

Hello,
I am a newbie here but I visit this forum on regular basis to find interesting informations about computers of my life - Speccies.

I have a small collection of Speccies and Timex computers and I connect them to my TEVION 50" Plasma TV via EURO/SCART connector.

ZX Spectrum 128K (toastrack) I use RGB - Scart cable and picture quality is great (best).
ZX Spectrum +2 (grey model) I use the same cable as above and picture quality is very good but not as good as from 128K (Why??)
ZX Spectrum +2B (black) I use RGB-Scart cable different from 128K & +2 "grey" and picture quality is great (best)

TIMEX 2048 - I use RCA (cinch) composite video to SCART and picture quality is acceptable (but I would love it to be better) I suppose there is no RGB out signal at edge connector so I can't improve picture quality. (am I wrong?)


48K and Spectrum+ - composite video modded - picture quality is awful !
I know the best idea would be to connect to my plasma TV via RGB.
Recently I bought Ferguson MA20 interface.

Thanks to zxbruno I found information about DIN8 video out signals at this page:
http://hardware.speccy.org/hardware/RGB-Ferguson-i.html

By the way the file RGB-Ferguson.rar located here: http://hardware.speccy.org/hardware/...B-Ferguson.rar is corrupted so I can't unpack it.

Dear zxbruno - could you please contact Mr Jose Leandro and kindly ask him to fix it? I wrote an e-mail to him some days ago and it still remains unanswered.

As for my Ferguson MA20 - I would like to use this by connecting to my plasma TV via EURO/SCART connector.

My questions:
1) R, G, B signals going out of Ferguson - are they TTL or analogue ?
2) I would like to use external PSU unit for this interface. Do you think cheap power supply like this http://www.ebay.co.uk/itm/LED-SMD-Ha...-/320919949330 could it be OK for such interface?

3) How about "inverted sync" signal mentioned at this page:
http://hardware.speccy.org/hardware/RGB-Ferguson-i.html

Does it mean this is negative or positive sync ?
If my plasma TV didn't accept such signal may I use 7404 (74LS04) video inverter the way mentioned here? http://www.twobits.com/RGB/sync.html

I hope someone here had succeeded in connecting Ferguson M20 to TV via SCART (RGB) cable and could share his experience.

Please forgive me my poor English. I hope you can understand me.
Thank you and kind regards,
Marcin

Jose_Leandro

Hi

ikci wrote: »

By the way the file RGB-Ferguson.rar located here: http://hardware.speccy.org/hardware/...B-Ferguson.rar is corrupted so I can't unpack it.

My questions:
1) R, G, B signals going out of Ferguson - are they TTL or analogue ?
2) I would like to use external PSU unit for this interface. Do you think cheap power supply like this http://www.ebay.co.uk/itm/LED-SMD-Ha...-/320919949330 could it be OK for such interface?

3) How about "inverted sync" signal mentioned at this page:
http://hardware.speccy.org/hardware/RGB-Ferguson-i.html

Does it mean this is negative or positive sync ?
If my plasma TV didn't accept such signal may I use 7404 (74LS04) video inverter the way mentioned here? http://www.twobits.com/RGB/sync.html

Sorry for delay . I've sent you a email this night

About your questions:

RBG is analogic but they are high level ( 4v). You will have to put resistors in your cable.

You can use many different power supplies. Indeed, I put in my article that you can use the original spectrum power supply because the rgb ferguson works with 10-11v.

Yes, the sync is negative and you will have to invert it. A 74LS04 will works

Bye

Jos? Leandro

Womble

As mentioned you will need to power the MA20 interface as it does not take any power from the Spectrum's edge connector. The Fergusson TV this was designed to work with gave a 12V DC supply out on one of the DIN socket pins.

I wired up this Frankenstein cable to run mine.

georgedb

Womble wrote: »

I wired up this Frankenstein cable to run mine.

Can you please publish your wiring? So, I'd need an 74LS04 and then I can use scart? VGA is not an option, I'm afraid? Are there any other output options? What's the grey connector, sub-D?

ikci

Thank you Jose and Womble for your reply.

I will try to connect my Ferguson to SCART RGB of my TV set.

I can see SYNC should be connected to pin 20 of SCART connector.
This connector needs 1V and Ferguson produces 3V so I will need resistor to decrease this signal.

As for negative SYNC - I can see almost all DVDs have negative sync at their SCART RGB connectors (signal out). Maybe this polarisation is suitable for TV and I don't have to invert this to positive?

Thanks,
Marcin

Jose_Leandro

Hi

ikci wrote: »

I can see SYNC should be connected to pin 20 of SCART connector.
This connector needs 1V and Ferguson produces 3V so I will need resistor to decrease this signal.

As for negative SYNC - I can see almost all DVDs have negative sync at their SCART RGB connectors (signal out). Maybe this polarisation is suitable for TV and I don't have to invert this to positive?

Thanks,
Marcin

Yes the first question.
The second one, well you can try negative sync and if it doesn't work, invert it :-)

Bye

Jos? Leandro

schombi

Hijacking this old thread. I also got myself a Ferguson MA20 interface and was hoping to connect one of my 48Ks to the round RGB connector of a Philips CM8833, but no success. From the previous postings I did not understand how/where to supply 12V and if/how to invert the signal?

1024MAK

If I understand correctly, the +12V was designed to come from the Ferguson TV.
If you use another display, you will need to connect a separate regulated +12V PSU to power the interface.

Mark

skagon

Hey, so you were the winner of last week? :D
I have two of these things, and the results are negative so far.
Basically, I've used an Extron unit, which is an RGB signal rectifier, connected to one of these 8820 RGB-VGA adaptors, and I hoped that the Extron's increased voltage and frequency range would help. However, no luck.
The MA20 was originally made to be used with two TV sets, the Ferguson MC01 and MC05. The 01 did not have a 12V power supply, the 05 did. Also, the 01 could accept TTL-level signals, whereas the 05 used SCART-compatible low-voltage 1V p-p signals.
I was lucky enough to get some spec sheets from a guy who had tested these TV sets for a British regulatory body (can't remember its name now) so he very kindly provided me with the specs.

To cut a long story short, I've tried the MA20 with any possible combination and couldn't get it to work. Truth be told, I did not invert the Sync signal, but other than that, I tried it with and without 12V power feed, various resistor values on the outputs, the lots.
Unfortunately, I didn't have an oscilloscope to see what the hell they're outputting, but... I made do with what I had.

If you do manage to get it to work, please let me know!

schombi

Yes, I was :smile:

I was chasing a MA20 from France for ages, but finally the seller did not reply any longer. Then I saw this one and to my amazement it really is in great shape. Only some traces of plasticisers from the cable, but boxed with instructions and for very fair postage.

Thanks for sharing your experience. Even though it does not sound promising, I will keep you updated if I make any progress.

skagon

Yes, I know... sorry.
I should note two things, though:
- the Extron does accept both normal and inverted sync signals, so it *shouldn't* need an inverter
- I never tested it on a TV through SCART
Somehow, hooking up an unknown device to my TV (without an OSC test) and frying it out, wasn't really appealing...

On another note, if you've got the manual, could you scan it for me?
I know it doesn't include any really useful info, but... just for completeness' sake. My MA20s are both unboxed.

schombi

Sure, I will do, once I?m back from my two-nights trip to England .

schombi

I created the PDF. It?s colored and about 2.2 MB in size. Skagon, could you please PN me your e-mail address? I guess if I upload the file to WoS, it won?t get anywhere at the moment?