CED VideoDisc and Player Discussion

[ChateauxFaygeaux]

Hey all:

I just spent a few weekends repairing an SJT100 player (purchased via eBay) with several problems with it and I thought that I'd share my experiences. My hopes are that the solution to one of the problems that I had, which was not covered by Tom's FAQ, might be of some benefit to someone with similar trouble.

Anyway, I get this SJT100 player from eBay. The thing appeared to have had much better days; the power button was jammed and the function motor belt was, predictably, nothing but goo. using a VERY small amount of "Rubber Renue" solvent (so as not to soften and damage the plastic), I was able clean up the belt pulleys enough to acommodate a makeshift spare belt from the loading mechanism of an old 2x CD-ROM drive. I intended to get the proper replacement at a later date.

So the function motor is finally providing mechanical power to the load/eject mechanism. That is, however, until I hear a snap. I remove power and find that on the right side, a small rod had broken. Later on I would find that this is called the "coupling transfer rod."

The coupling transfer rod, being all-plastic, was not so easy to repair; all that I could accomplish with superglue was a still-broken rod and sticky hands. At this point, I would have to obtain some replacement parts. I put in an order at CEDatum and ordered a replacement coupling rod, function motor belt, power switch (the existing one was broken beyond repair), and since I didn't know what else might need repair, I also ordered the service education manual. The manual would prove itself useful as I will mention later.

The parts came a little under a week later, and after about a half hour of soldering in the new switch, installing the coupling rod, and installing the new belt, I was pleased to discover that discs would load and play (quite well, actually), but after I pressed the eject button, the turntable would spin down but the player refuse to disengage the disc. The turntable tould "kick" back and forth, presumably to find a "home position" that would allow it to engage the transfer rod. Marking the outside edge of each of these four "home position" locations with a marker, I would press the reject button and grasp the inside of the turntable with the disc inside and hold it in one of these four positions. After doing this, the load/eject mechamism engaged and I was finally able to remove the disc.

I was baffled; I couldn't detect any mechanical problems with the turntable. After all, the turntable wasn't sqeaking while running, and the picture did not indicate any kind of color shift that might indicate an improper turntable speed. With nothing to lose, I read the service literature and followed the troubleshooting chart for a malfunctioning turntable. It turns out that a symptom of a missing turntable output phase (0B in this case), the turntable will continuously hunt for a home position, and in some cases, the turntable will not engage from a particular position until the turntable is manually rotated. I verify that while all four phase outputs are being generated by the mechanism ic (U5901), I am not seeing a pulse on one of the quad op amp outputs (U5902) . Looking at the rough schematic on the service manual, this output turned out to be associated with phase 0B.

Anyway, after a trip to Radio Shack and $1.50 later, I install a replacement op amp and find my troubles are all solved and I have a player that loads, ejects, and plays like a champ. Of course, I spent more repairing the player than I spent on it, but to me, the fun thing about CED collecting is the uniqueness of the technology, and fixing the player is more satisfying than watching anything on it. Of course, that might be an indication that I should try to find some more discs. I just wish that I didn't always have to get this stuff through the mail. I live in Indiana, where both the discs and players were manufactured. Why is it that I can never find this stuff in a garage sale or anything?

Anyway, I apologize for the long-winded post, but I was maybe a little too proud of myself for my successful troubleshooting, and couldn't help but blab about it. I hope that in any case, my story was of some entertainment and utility to someone out there.

[hbo3]

Just wanted to say cheers to you. It's people like you who are valuable to our community. You actually posted your good experience with your player rather than the usual "Where can I get a stylus" or "I have some discs and a player to unload" (Although those postings are valuable too).
_________________
Sk8 Or Die on Rockville Road . . .

[mnallard]

Holy Cow...you actually taught me something about the J/K Line. Sounds like I need to get me one of those manuals. I just won an SFT-100 W off ebay and am currently waiting for it and STRIPES to arrive. If they don't work, I'll be needing help. I'm not familiar with the F/G line of RCA Players.

I agree, it should be easier to find these at garage sales, but those who do have them in my area have either thrown them away or handed them to someone else not knowing how collectable they are. It's a shame too.

Congrats on your repair. Incidentally, what was the part number you used to replace the IC? Does that IC still exsist? And yes...just repairing the player to watch it work is one of the best rewards of all...although watching a movie on it from time to time has its rewards as well!

[Ron Rendfeld]

I think it is great that you were able to fix your player and share your experience with the group.

I live in Indy and have purchased a few discs from a thrift shop ( Thanks Duckie)and a Goodwill store (Thanks Matt) mentioned in an earlier post.

I'd like to swap some of the discs I have. Where in Indiana are you located?

Ron in Indy

rsrendfeld@aol.com

[ChateauxFaygeaux]

[jonhaggis]

I picked up the aforementioned for two bucks at a Chicago thrift store; the machine loads fine, I think it's connected correctly as I get a blank screen, but the display sticks on "L" and the disc doesn't seem to play, no signal.

Any advice/ideas for someone new to CEDs?

[Guest]

Glad to hear about the success of your repair.
Good to hear from people who are interested in CED.
And not just the ones trying to sell Part 1 of "On Golden Pond".

[ETEK1107]

Hello All,

I just finished working on a SJT-100, & it works perfectly. Also I still have my Trainnning Manual for the origional SFT100 (all mechanical machine). It is in one of those loose leaf Notebooks, & I can copy any pages you may need. You can E-mail me if needed. F.W.Rasmusson@juno.com I would be happy to assist you if I can. I never did see any great numbers of these come in for repair, since the BetaMax, & the VHS machines were all ready in production. Interestingly enough, this CED Technology goes way back to the 1960's, and somewhere there was an article published in Electronics World or another Magazine like that back then. I was told when going to RCA School, that the honchos at RCA never thought delivery of movies in this format would ever take hold. Along comes first Laser Discs, then RCA brought back their 20 year old technology then (1978 or so) to keep from having to pay royalties for using the laser system. The rest is HISTORY. I still maintain a very few of these machines for our own use & have even fewer Discs. My hat is off to any and all of you who preserve not only the Machines, but the Media as well. GOOD LUCK ALL.

[Reinhart]

Adding in the two cents for the J/K line:

The plastic part that drives the disc support rod on the main advance gear will break if the turntable is not in the proper position when the mechanism returns to the home position when powering on after the belt replacement.

Note that the turntable has four holes on it evenly spaced in quadrants.

BEFORE TURNING ON after the belt replacement, make sure that one of the holes on the turntable is directly above the metal rod that supports the disc during loading and unloading.

Apparently, the SYSCON doesn't try to correct the position of the turntable before driving the advance mechanism when turning on (likely because it never has to when the mechanism is operating properly). - Reinhart

[Reinhart]

"Along comes first Laser Discs, then RCA brought back their 20 year old technology then (1978 or so) to keep from having to pay royalties for using the laser system."

Tom Howe has a great history about the development of the CED format from its inception to its release.

Blaine Oz also has a great history about the development of LaserVision that is in the same vein: www.blamld.net

CED was put on hiatus in the late 1970s because of RCA president Edgar Griffiths and his attitude towards anything that essentially risked being unprofitable. He made the decision to resume likely due to a December 1978 "Fortune" magazine article that critiqued him for not taking risks on such products.

This delay would be both good and bad for CED. It was good because the delay did allow time to further refine CED, which increased the playtime per side and changed the disc manufacturing from a failure-prone multi-layer construction to a simple carbon PVC disc. It was also bad because it meant that CED would be released too late to unseat the VCR market, particularly VHS.

These points were taken from Tom Howe's "Memories of Videodisc" page on his fantastic CEDMagic site.

As for LaserDisc, I doubt that RCA ever planned on making a laser product. First was the feasibility factor, or at least in 1960s standards, so the decision was made to go with a stylus-based system. Then, MCA would announce laser videodiscs under the MCA Disco-Vision banner after purchasing the company that held the patents for the basis of reflective optical discs: Gauss Electrophysics. Philips would later be involved and, much later on, Pioneer.

1978 saw the consumer release of LaserDisc with the Magnavox VH-8000 (with initially incredible popularity that quickly died due to quality problems with both software and hardware that never were corrected until Pioneer took over from MCA). Points taken from Blaine Oz's Blam LD's "DiscoVision" site.

1981 would see the consumer release of CED with the RCA SFT-100W (which had better quality control initially when compared to LaserDisc's coming).

As for licensing fees: ANY manufacturer that makes a product that uses the concept of reflective optics on a disc must pay royalties to Pioneer's DiscoVision Associates licensing company. This includes LDs, CDs, DVDs, MDs, Blu-Ray, HD-DVD, and etc.

In fact, DiscoVision Associates won a lawsuit against Philips and Sony for a patent violation for the Compact Disc. They also sold a license to Apex electronics for DVD player manufacturing to preclude a patent violation lawsuit. - Reinhart

[Guest]

Regarding history: one title takes care of all these questions quite well. Nicely listed in (you guessed it!) CEDMagic -

The Business of Research: RCA and the VideoDisc, Margaret Graham, Cambridge University Press, 1986.

Available from Amazon in hardcover or paperback.

A must-read for any CED enthusiast, it covers the entire path of CED at RCA from initial research directions to marketing to the fallout from its spectacular failure. If you find an old copy the title and subtitle are reversed, as the book is now (rightfully so) marketed as an invaluable document on American science-based corporate research.

[macgyver]

Reinhart, You gave a web site for lazer video as www.blamld.net.
Tried and could not find it even in a search.
Then tried www.blamld.com.

That's where I found it .com not .net I know it's confusing.

Since I also own a pioneer lazer disc player am grateful you supplied that information but thought had better mention in this forum where page is actually to be found.

Thanks for bringing that info to this forum.
Macgyver