Who's interested in having an S-Video Modulator?

[Axelay]

Mine has arrived now too, thanks Bryce!   

[Executioner]

It would be interesting if you could extend the sync signal by 1 microsecond (always) to see if that fixes the problems with Ghost & Goblins etc.

[Ynot.zer0]

Okay, so it is finally time for me to hookup my S-Video Modulator.
I purchased a multi-adaptor VGA/  S-Video box from eBay.  I had a CPC video connector previously removed from an old monitor (worked okay when connected to a PSOne 5" screen)
I was looking at this diagram:
http://www.cpcwiki.eu/imgs/8/84/S-VHS_External_Classic.PNG
I thought I'd make a bit of a guess on what colour cable the 'Sync' actually was.  Turns out I'm not being very successful.
I have
Blue -> Blue
Green -> Green
Red - > Red


Now I have White, Black and Brown cables left. I've tried various combinations of guess work and nothing seems to work.


Can, maybe Bryce? tell a non-electrical engineer person, what colours map to those pins in the diagram?


btw - I'm powering the S-Video Modulator with a 4xAA battery pack (is that okay?).

[Bryce]

Hi ynot.zero,
        I'm not sure I understand what you mean. The grey wire in the linked diagram is Sync (ie: the one that says Sync beside it). Or are you referring to the original cable that was connected to the CPCs Monitor? If so, I'm not sure what colours were used. Either way, if you only have the GND connected to the batteries and not to the CPC GND also, then none of them will work because the signals will be floating.

Regarding your 4xAA Batteries: Aaaaaarrrrrgggghhhhhh!!!!!!!!! Nooooooooo!!!!!!! The absolute max voltage for the AD724 is 5.25V and you're feeding it with 6V !!! The Modulator will probably die quite soon.

Bryce.

[Ynot.zer0]

I'm not sure I understand what you mean. The grey wire in the linked diagram is Sync (ie: the one that says Sync beside it). Or are you referring to the original cable that was connected to the CPCs Monitor? If so, I'm not sure what colours were used.

Yes, the grey/white wire in the linked diagram is sync, what I wanted to know was what colour wire was it coming from the CPC connector.  I'd cut the cable about 10cm from the CPC, so I do not know what cable goes to what pin, I can only guess from colours.  Okay, if you do not know I'll apply trial and error.

Either way, if you only have the GND connected to the batteries and not to the CPC GND also, then none of them will work because the signals will be floating.

I have it setup so that GND is connected to both (just working out what cable from the CPC Connector is actually GND....)

Regarding your 4xAA Batteries: Aaaaaarrrrrgggghhhhhh!!!!!!!!! Nooooooooo!!!!!!! The absolute max voltage for the AD724 is 5.25V and you're feeding it with 6V !!! The Modulator will probably die quite soon.

oops.  well, it wasn't for long, maybe 20 seconds at most... about 20 times    okay, I've now attached a variable power connector from the mains and set it to 4.5v


Well, I still get nothing (maybe a little LED on the modulator could be fitted to v2.0 just to let me know it is has power?) but I'm suspecting my adaptor (s-video to vga) is at fault as that also has no led letting me know it is working either.


hmmm.... okay, I'm going to revert back to my PSOne 5" LCD screen configuration to clarify what the black, brown & white cables actually were (should have looked that up before I dismantled it, I suppose    ).


I just remembered, I do have this http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=250675162632&ssPageName=STRK:MEWNX:IT#ht_3605wt_1154
ordered and "in the post", so maybe I'll have better luck with that?

[Bryce]

If the power supply is really only supplying 4.5V that will be to little. The AD724 needs between 4.75V and 5.25V (ie: ideally 5V). Why don't you use the 5V that supplies the CPC, that would seem the easiest and most logical choice.

The ebay device you've ordered does exactly what the Modulator does, so if you use that, you don't need my Modulator at all (very nice device though, and cheap!).

Bryce.

[Ynot.zer0]

If the power supply is really only supplying 4.5V that will be to little. The AD724 needs between 4.75V and 5.25V (ie: ideally 5V). Why don't you use the 5V that supplies the CPC, that would seem the easiest and most logical choice.

My track record today is not good.  My laptop LCD screen died this morning... 
I couldn't get the Modulator to work 
I just reconnected the PSOne LCD, it showed me a lovely CPC screen for about 10 seconds.. then it died 


I think it's a sign... I'm leaving everything alone for the rest of the day!

The ebay device you've ordered does exactly what the Modulator does, so if you use that, you don't need my Modulator at all (very nice device though, and cheap!).

Yeah... but it's about 4000 times bigger than your lovely device!

[Bryce]

Was the lovely 10 second picture produced using my Modulator (and with what voltage source), or a different setup? Do you know what died?

Bryce.

[Devilmarkus]

Here's my overhauled MP2...
It also has a composite jack. But thats not from the new modulator.
It's a MP2 modification.

The new modulator works fine, as you can suggest

Thanks again, Bryce, for your great work!

BTW.: I used much hot glue But it's very stable now.

[Bryce]

Stable?? That's bullet-proof.

Bryce.

[Devilmarkus]

Stable?? That's bullet-proof.

Or so....
Well the aspect looks like dinosaur-sperm, but the result is ok.
And the result was important for me
And from the outside it looks quite well...

[robcfg]

Wery well done, Markus!


Now you have an MP2+ modulator! 

[Devilmarkus]

Well, my modulator inside the mp2 makes some trouble.
I get stripes on the left screen side and also the screen flickers sometimes.
Any idea how to avoid that?

[Bryce]

Hmmm, that's a power-supply problem, Pentagon had a similar problem so I made a special version for him. I can do the same for yours, but you'd have to send it back for the change :S

Usually switching it off and back on again should solve the problem in your case.

Bryce.

[Ynot.zer0]

Usually switching it off and back on again should solve the problem in your case.

[Bryce]

And I can even do it with his accent too

Bryce.

[fgbrain]

@MaV,

Will you build one for me? I can pay through paypal..

What about a proper power supply for my old 6128? With dual voltage needed for the drive as well..

[MaV]

@MaV,

Will you build one for me? I can pay through paypal..

What about a proper power supply for my old 6128? With dual voltage needed for the drive as well..

Sure I can. I'll send you a PM.

[OCT]

Well, my modulator inside the mp2 makes some trouble.
I get stripes on the left screen side and also the screen flickers sometimes.
Any idea how to avoid that?

After quite some time out of town, I finally had the chance to try mine today as well.

Not only am I seeing the same kind of distortion at the left edge http://www.cpcwiki.eu/forum/index.php?action=dlattach;topic=2109.0;attach=1781 but additionally the picture I get is just black&white (or shades of grey for that matter).
However, I have got to say that currently my screens are not TV sets (will try with one ASAP) but a PC monitor connected through a "Supera Color LCD TV Box" (I have yet to try a "PremiumBlue V2V" = Pollin.de item 721190) and a projector featuring S-Video input, and the system is a French CPC6128plus with a British cartridge. So this is not to say that anything might be wrong with Bryce's product!

The modulator is installed internally according to http://www.cpcwiki.eu/index.php/File:S-VHS_Internal_Plus.PNG - "Devilmarkus style" (http://www.cpcwiki.eu/forum/index.php?topic=2109.msg23079#msg23079 and subsequent) but with a small indentation to the inner side of bottom housing so as not to have the entire width of the PCB protrude from the case, and using a shielded 6-pin cable soldered to the modulator's top pin field (and with the shield connected only at the floppy drive side).
If there was a wiring error, my understanding is that I should not be getting any picture at all.
I also found the CPC's circuitry cannot drive both the modulator and a monitor (RGB output) at the same time - contrary to the experiences in http://www.cpcwiki.eu/forum/index.php?topic=2109.msg23136#msg23136 through http://www.cpcwiki.eu/forum/index.php?topic=2109.msg23171#msg23171 the S-Video output will be heavily distorted at least as soon a cable several meters long is plugged to the 8-pin monitor socket.

Just wondering whether the monochrome grayscale picture might be due to the fact that this appears to be an originally French Plus, probably not one with the keyboard relabelled from a model made for other markets. Did the French version have anything wired for a different video timing (in comparison to UK/German models) due to the SECAM system (still dominant there in 1990), and how may that be changed?

[Bryce]

Hi OCT,
      the black and white picture is when the TV/Monitor thinks it's getting a composite signal instead of S-Video, so you need to change modes in the TV or use a TV that automatically detects the S-Video.

The distortion problem really is an issue with the modulator. I've been investigating this some more in detail, because there are now three devices that show this problem. The issue seems to be with power supplies that rise too slowly. ie: if the power supply takes too long to go from 0V to 5V when it's turned on, then the AD724 seems to start up wrong. The easiest solution I found to solve this was to add a switch to the modulator, so that you can turn on the power supply first and then turn on the modulator. This worked on almost all simulations, but if it doesn't help, then you need to send me the modulator and I will make some changes to it. It seems to be a problem with the second batch of AD724s that I got. The first ones all worked perfectly, but I suspect that the second batch were cheap copies. That's the risk of buying ICs from questionable sources.

Bryce.

[OCT]

      the black and white picture is when the TV/Monitor thinks it's getting a composite signal instead of S-Video, so you need to change modes in the TV or use a TV that automatically detects the S-Video.

None of the (admittedly few) devices I have here will let me do this (the point of using the modulator in the first place was that I just don't have the place for a CRT):
Both have dedicated Cinch (Composite Video, or FBAS as the German acronym goes) and separate S-Video (Y/C) connectors, the latter of which hence aren't switchable to (or from) Composite Video at all.
I did get some (blueish, albeit still wrong, as in cyan-on-blue, and bleeding) color the moment I set the projector's S-Video mode to SECAM, hence my question whether the French Plus had any obscure difference in video timings.

So either the horizontal left-edge "jitter" makes the S-Video inputs get the C wrong somehow (it would be dependent on the video standard IIRC), or there's just the luminance part properly coming out somehow (on which sync is, as for component YPbPr, right?). No scope around to tell you more I'm afraid.

The moment I get my hands on an S- to Composite Video adapter plug, I'll see whether color might be detected in Y&C rolled into one.

The distortion problem really is an issue with the modulator. I've been investigating this some more in detail, because there are now three devices that show this problem. The issue seems to be with power supplies that rise too slowly. ie: if the power supply takes too long to go from 0V to 5V when it's turned on, then the AD724 seems to start up wrong. The easiest solution I found to solve this was to add a switch to the modulator, so that you can turn on the power supply first and then turn on the modulator. This worked on almost all simulations, but if it doesn't help, then you need to send me the modulator and I will make some changes to it. It seems to be a problem with the second batch of AD724s that I got. The first ones all worked perfectly, but I suspect that the second batch were cheap copies. That's the risk of buying ICs from questionable sources.

Wait a minute, wasn't the second batch the more expensive one? "Moonshine chipmaking", what has organized (cyber)crime come to these days... <sigh>

But seriously, the way you've suggested in http://www.cpcwiki.eu/index.php/File:S-VHS_Internal_Plus.PNG the modulator seems to be "always on" (probably got move the red wire to the pin labelled 2 on the right?) and not even (low voltage) power-cycled along with the CPC('s cartridge bay switch - the modulator's +5V would have to be on the far end of the yellow connector for this I guess). And this way at least, I couldn't get an undistorted, full-color picture any of the times I (as an "IT Kraut") inevitably already tried "turning it off and on again" (no matter which of the plugs was pulled, mains or otherwise).
Sounds like I'll have to unsolder the modulator to let it wing its way back to you, unless you can let us know what component(s) to change (if that can be done at all without high-end equipment).

[Bryce]

I sent you a PM. This issue needs to be solved.

Bryce.

[OCT]

I sent you a PM. This issue needs to be solved.

Thanks. I just wanted to try and make sure it's not anything related to my setup around here, such as the S-Video cable, some kind of noise or ripple from the power supply interfering with the chroma quadrature modulation, or simply a French CPC oddity.

I'll attach a video as soon as I've figured out how to make VLC save it as a .mpg usable in Windows Media Player and below the 2 MB size limit...

[rave_dj]

Hi. I´m rave_dj and I rarely post anything, but I love to read all post because so many times I can learn (or remember) something. My first amstrad was a CPC464 back in 1986. In 1988 I could get a CPC 6128; and from 1990 to present I work mainly with PCs.
I´ve also read various retro hardware spanish forums (amstradcpc, zonadepruebas, amstrad.es...) and some blogs.

And with the introducing finished, I´m interested in one of these modulators, but with composite output. I know, I know... I arrived late. But If the solder industry starts again, I´d love get one of these but with composite.

I have a 464, 472, 664, 6128, 464+ and 6128+ besides 2 monitors: GT65 and CTM644 (haven´t any for the pluses), but It will be great to use them in a bigger screen.

Surely you have noticed my awful english, sorry 

[Bryce]

Hi Rave_dj,
      just sent you a PM....

Bryce.