CED VideoDisc and Player Discussion

[CEDatum]

Early next year Television Broadcasting on VHF channels (analogue) will cease. If you own a CED player with only a CH3/4 TV output connector your player will not work with a new TV receiver.

CEDatum has designed a A/V ( Audio/Video ) module that can be installed in your CH3/4 CED player to provide an Audio and Video output. These outputs can be directly connected to any TV and the new flat screen TV sets have these inputs.

The A/V module Audio and Video outputs are regular RCA connectors and are installed on the back panel of your player. The A/V module is wired directly into the audio and video baseband signals generated in your player and these are buffered to provide isolated Audio and Video signals. The existing Ch3/4 connector can still be used.
The A/V module output signals are high quality. - ie -the video signal is the same as that from the SJT400 video connector.

The development A/V module boards have been hand made and are fairly expensive. We can reduce the cost of the module substantially if we have the circuit board manufactured. We can do this if there is sufficient interest from CED hobbyists for this module. Qty 50 is about the minimum we require to have the board manufactured.

We would really like to hear from you.

The A/V modification could be available in the following forms:

A/ A kit - The printed circuit board and a parts list, assembly and installation instructions - Something like a Radio Shack kit .
B/ A working and tested module with installation instructions for your player. - There will be approx 7 solder connections to be made.
C/ You send your player to CEDatum and we will install the A/V module and fully check the operation of your player.

Let us know if you would be interested in A or B or C. Send your comments to our e-mail address: cedatum@ccrtc.com Thank you.

[Jesse Skeen]

Everyone really ought to be using a stereo CED player anyways, especially on a new TV (how do CEDs look on a flat-screen or DLP set anyways- I'm finally going to get one or the other in the coming year and wonder how it holds up on those.) I would however like to see something like this to add A/V outs for the old video game systems, like the Atari 2600 & 5200, Colecovision and Intellivision. These have to be hooked up to analog TV tuners to work- I've figured if they stopped including those in new TVs I could still hook them up through a VCR, but direct A/V outs would look and sound a whole lot better.

I'm not sure how quickly analog tuners are going to go away- low-power stations in the US will still be on after February, and analog stations in Mexico and Canada plan on staying around for some time to come.
_________________
Videodisc and stereo sound- there's no better value around!

[Rixrex]

Please excuse my being devil's advocate here, but I honestly don't see this as a better option than just getting another player already designed for AV output, for two reasons. First, if it's going to be relatively expensive, then why not just spend the money on an original player with AV out?

Secondly, I personally don't think it's wise to alter a piece of vintage equipment from its original form. But I realize that point is entirely personal, and based upon my experience collecting vintage items, and how they are valued.

Alternately, one could merely use the old standby VCR to do this, or even purchase a small device that converts RF out to AV, they are not expensive. One could also keep the analog set for CED viewing. I have one of my older CED units setup on a older 32" console with a betamax VCR, and it works fine and looks good that way.

Not everyone would do this certainly, but this setup is in my vintage-styled living room, and separate from the 'home-theater' room. It's also a better setup for us when guests are over because then we don't have to contend with a booming, in-your-face home-theater while some of us are talking. And a nice, good-working console-style set of up to 36" screen can be had pretty cheaply now.

I also have a newer AV model setup on the big screen, but routed through a DVDO video enhancer/line doubler that converts it to higher resolutions that work to view CEDs on the big screen to good effect. I found this to be money well spent because the enhancer also accepts several other devices for conversion to Hi Def. Anyway, this is just my opinion, that's all, and everyone's free to do what they see as best for them regardless, and I must add that it's heartening to see folks use methods of keeping the older electronics stuff usable in a modern world.

[RT9342]

Stereo players are nice, of course, but I doubt there are enough of them out there for all CED collectors to have one. I've been thinking about trying to get an SGT-200 (since I'm one of the few oddballs that prefers the SFT & SGT design over the SJT and SKT design, I guess because that's what I grew up with and I have more experience servicing that type than the SJT/SKT chassis), but those, and all the stereo models in fact, seem to be very scarce.
I have actually added AV jacks to RF-only models, and it can be done easily without any alteration or permanent changes to the player (other than the fact that a couple of solder joints have new solder, and that there's an extra cord hanging out the back). You can just get an AV cable and cut off the plugs on one end. The service label glued to the bottom cover shows which test point is which. You can solder the audio wire directly to the audio test point (though installing a capacitor in series would probably be better), and you can connect the video wire to the video out test point (but you'll probably need a resistor in series to control the brightness - I think a 75-ohm will do). And just solder the AV cable's shielding to one of the metal shields on the circuit board. No need to drill holes - if you route the cable just right, you can feed it out the back, where the power cord comes out. You may have to play with the cable position a little, but there's a space where it can come out without obstructing anything upon reassembly.
It's possible to do the same thing with old video game systems. In fact, I've been able to get S-video and STEREO audio out of an Atari 2600 (to get stereo sound, you do have to cut one trace that connects 2 adjacent pins on the CO10444D chip, so if you don't like the idea of cutting traces, just leave the audio mono). I haven't tried doing this with the Atari 5200 or the ColecoVision, but I do know that S-video is available from the 5200 (I'm not sure about stereo audio though, but it may be possible), and if I'm not mistaken, the ColecoVision video chip actually generates component video (Y, R-Y, & B-Y). But I'm not 100% certain on that. I do know that you can get RGB output from a Nintendo, but you have to replace the RP2C02 chip with an RC2C03 or RP2C03 (which can be obtained from junk Playchoice 10 motherboards or from certain arcade ROM sets, like Duck Hunt).

[Rixrex]

I haven't found it that hard to find a stereo player, even the SGT 200 or SGT 250. I suspect there are actually enough stereo players around for collectors, as the number of collectors isn't all that tremendous.

Anyone can do as they wish with their CED player since they are the owner, but speaking from the experience of vintage collectibles' values, original and unmodified is always more valuable, relatively speaking, than an item that's been adapted in some way. I mentioned that only as a consideration, not a requirement for keeping something original.

Those with technical expertise are naturally inclined to view an apparatus and envision ways to improve it. or adapt it for a preferred use. That's not irresponsible, and actually helps to advance any technical area. So while mentioning the consideration of an originally kept CED player's value, I wasn't intentionally deriding those who would make changes to their players. However, I would say that if the change is more expensive than purchasing an original AV model, or if there is a way to do the same thing with an off-board inexpensive adapter, that might be a preferrable solution.

[CEDatum]

RT9342 suggests a modification to a CH3/4 only CED player to provide video and audio outputs by connecting to the tests point on the circuit board. CEDatum associates evaluated this approach and found there are limitations. And these limitations could degrade the quality of the picture and sound.
Video : The video test point has too high an impedence. This can result in:
1/ Loss of picture detail when a long video cable is used to the TV or video box.
2/ The video output is not 100 IRE and this will effect picture brightness and chroma (color )level on some TV receivers.
3/ We found that an interference pattern could be fed back into the player and produce beats and annoying patterns in the picture. - ( A VCR hook-up in our example)
4/ On connections to some external video equipment or TV the existing CH3/4 output of the player was degraded.
Audio: The CED stytem uses audio pre-emphasis. This is applied during disc mastering. In order to achieve the best audio noise level and a flat frequency response ( ie- best sound) de-emphasis must be used in the player.
5/ The audio at the test point has only partial correction so the audio out sounds 'harsh' on a good audio system.
6/ There is a possibility of feeding back an external signal into the player test point and this will be added to the audio on the CH3/4 output.

NOTE. If the video and audio test points had been designed to provide Video and Audio output directly then we can be sure that RCA would have used them to reduce the component count and therefore the manufacturing cost of the player.

The CEDatum A/V modification has buffered and isolated Video and Audio outputs. The video circuit is very similar to the one used on the SJT400. The audio output is via a transistor amplifier and de-emphasis is applied. This is good engineering practice.

Daxi Don for CEDatum.

[Rixrex]

All good reasons to get a player that has AV output as original for your modern set.

[RT9342]

Okay, that would probably be the best solution then. I just wish I knew where everyone's finding all of the stereo models. I do see them occasionally on eBay, but not too often. But perhaps it's because I don't check often enough. I think part of the problem, too, is my location. I live near San Antonio, TX, and around here, only the cheapest, crappiest VHS and DVD players ever built is about all you'll find at any pawn shop, thrift store, garage sale, flea market, etc. I don't even think people buy Blu-Ray around here. (I had to get my Blu-Ray player online, and if I happen to find a Blu-Ray disc section in a store, it's usually a small shelf about 3 feet wide, with one copy of each of the 50 or so movies.)

[RT9342]

Hmmm.....after posting that last comment, a whole bunch of SGT-250's and SJT-200's show up on eBay. I'll take back what I said, and I appologize for all of the bad information I shared on this post.
After I had lost my old TV and CED stuff in a flood, I obtained a video monitor (with no tuner or RF input) to use as a TV, and a CED player with only RF output, so I was trying to come up with a cheap and simple alternative to using a VCR as a demodulator. It actually worked pretty well on my monitor and a couple of other TV's that I tried it on, as well as making backup copies on VHS, but I will admit that the audio signal did seem to have louder popping noises whenever the stylus came across a bad spot on the disc, and since I didn't actually measure the impedance, I was not aware of the point that Daxi Don pointed out concerning using longer cables. I was aware of the IRE level problem, but I played around with different series resistor values to get an improved picture (using no resistor was too bright, and if I remember correctly, 100 ohms was a little too dark, but I think 75 ohms was okay). But as Daxi Don mentioned, and I'll admit, it's a far from perfect approach. I think I'll just get me one of those SGT-250's that recently showed up on eBay.

[dcayea]

Just an idea way out there in the wings... Wouldn't it be something to try to make some kind of upscale converter board?

[RT9342]

I like that idea, but I'm just not sure if any of the folks still interested in messing with CED stuff have the know-how to build such a board. It would probably be pretty complicated. They are able to incorporate the technology into DVD players and Blu-Ray players with DVD compatibility because the signal is pretty much computer data, which has to go through a digital signal processor anyway, so it's just a matter of having the processor scale the graphics to a different resolution and spit out a digital bitstream on the HDMI cable. And if I'm not mistaken, most DVDs actually have the video stored at a slightly higher resolution than standard TV resolution (for the zoom feature, I guess), which would simplify the upconversion process. But to do the same with an analog video signal at normal resolution might be quite difficult. I've seen commercial SVHS VCRs that use digital circuitry to correct the picture and the time base, and to make the video available in S-video or even component video on some models. There are two fairly large boards in those VCRs to do that, both of which are packed with hundreds, if not thousands, of parts and custom processors (something you probably couldn't buy for small production, like building CED upconvert boards). And those don't even upconvert the picture; they simply make corrections and allow component video output, which normally cannot be easily derived from a VHS tape, due to the way that the color carrier is encoded and decoded. However, being that those commercial VCRs play movies with near-DVD picture quality, while a consumer VCR playing the same tape has a really nasty picture quality, I would like to see what an upconvert board would do to the CED picture quality. Hopefully someone can prove me wrong and build such a board.

[Rixrex]

Unless you're an engineer, I think a better idea is to purchase one that will upscale from standard to higher definition. Some of these are cheap junk, but there's some great items from DVDO, probably the best of all the upscale converters, that can upscale SD output to a whole variety of HD formats. I have one of my CED players placed through a DVDO and it has an amazingly nice picture on the HD TV.

For the beginner with a widescreen TV, I suggest either the DVDO Ultra or the DVDO HD. Ultra goes up to 480 progressive, and HD goes up to 720p and 1080i and 1080p. Both have scaling options that allow for letterboxed versions to be formatted as anamorphic widescreen, like DVDs. and they also have a format that puts sidebars on 4:3 video in a range of grays to black. None of these are manufactured new now, but are available used for a pretty good price.

[RT9342]

Cool - I had never seen those before...but all of the ones I saw on eBay were selling for $600-$900. I don't know...I like CED's, but for that amount of money, I could probably just get most of my CED movies on Blu-Ray. Then again, I would have to sit there and let the Blu-Ray player show the FBI warning in English, French, and Spanish, and then skip any previews or commercials, then select "play movie", and hope that my Blu-Ray player doesn't glitch up and require rebooting. Funny - my CED player is almost 30 years old and has a worn-out stylus, yet it almost seems more reliable than most of the latest DVD players and Blu-Ray players that I've seen (except for my Pioneer DVD-V7400...but it's an older machine, and not your ordinary, buy-at-the-retail-store DVD player).

Actually, my CED player looks pretty good when connected directly to my HDTV with audio/video cables. But the main problem I noticed (and I have the same problem when watching movies on my old PR-7820 laserdisc player) is that the TV seems to want to "toggle" between 2 different brightness levels for some reason. Usually, it brightens the screen on dark scenes and darkens it on bright scenes, and most of the time you won't even notice it, but occasionally it just changes the brightness in the middle of a scene for no particular reason. Maybe it's just something with Samsung HDTVs. Or at least their CRT HDTV's. It's been a good TV other than that problem - probably the cheapest TV with 1080 resolution (and it's funny because it actually looks like a flat LCD TV on a stand, until you notice that the screen has that CRT screen look, with the thick shiny glass and the dark gray phosphors behind it...and when you look at the back, you see that the "stand" is not really a stand and that the TV has a big butt in the back).

[Jesse Skeen]

DVD recorders seem to have that same brightness problem too- part of converting analog video to digital. My 2nd-generation Philips was really bad with this when transferring VHS or Beta tapes. Sometimes the contrast would be completely out of whack requiring starting the tape over again, and sometimes a glitch in the recording would make the brightness levels change too. My newer one is better but it still changes the brightness levels during some tapes- and no, it's nothing to do with copy protection, these are tapes recorded from TV.
_________________
Videodisc and stereo sound- there's no better value around!

[RT9342]

Interesting...well at least I now know it's not just my TV. I guess some kind of upconversion box that didn't do that would solve the problem.

I was thinking, though.....with all the talk of finding a way to upconvert CED's, and even Ron's comments of adding digital freeze-frame, I'm thinking that the best way to achieve maximum CED video quality would be to build some kind of custom analog-to-digital converter that took the video from inside the player, after demodulation from the FM signal, but prior to upconverting the 1.53MHz color carrier to 3.58MHz, and prior to all dropout compensation. I realize that the color carrier conversion circuits are needed for the armstretcher, but if the unconverted signal can be tapped, using some kind of MOSFET or CMOS circuit, then perhaps a circuit could be built to decode the color signals directly from the 1.53 MHz carrier, rather than a 3.58 MHz carrier. Then from there you could convert it to a digital signal and utilize digital dropout compensation (like my commercial VCR, which appears to use video from the previous frame, rather than the lines above the bad spot). Since the video would be digital at this point, it woul be possible to convert it to an HDMI signal, and to even add a digital freeze-frame option (just retain the last video frame upon entering pause mode). If you tapped into the control buttons and/or the display LEDs, you could even implement on-screen displays. Maybe that's a bit overkill, but I think it would be neat to have an HDMI port on a CED player, but even neater if the HDMI ouput included video processing from the raw video signal, digital dropout compensation, freeze frame, and on-screen displays, while retaining the original look and operation of the old machine. I'd like to try to build such a device, but as many of you know, my electrical engineering skills aren't all that great. I am good with digital logic gates, but this project would require more skill than just that. I'd love to see other folks attempt to build such a device.