Pioneer LaserDisc Player Teardown - The Electronics Inside

[@Dirtyz1234]

I still own a laser disc player for one reason. Star Wars Episode IV theatrical release

[@a531016]

Ahhh, good shout! Any sign of disc rot? I know it's a thing, but I have yet to see one in person?

[@TryAdaptLearn]

Good explanation including the history. It’s amazing how far we progressed in 200 years and eve the last 40+ (since laser disc) to store and retrieve audio and visual data.

[@a531016]

I heard once that any new technology takes about 50 years to go from "a new way to complete the same task" (think word-processing replacing type writers). I feel 1960 to 2010 was that period for electronics and computing? And of course, there were a few missteps and dead ends along the way!

[@EarMaster55]

"I hope you agree with me. And if not: You're wrong!" 😂

[@a531016]

Nooo, I would never say that! But...

[@chrismcovell]

"SAVE THE EARTH" written on the main PCB. :) I appreciate the sentiment.

[@a531016]

Optimistic isn't it?

[@dykodesigns]

The metalwork has a lot of indentations in it, they may seem random but they have a mechanical purpose. They stiffen the sheet metal which makes it harder to bend it.

[@a531016]

Absolutely, the top spindle support had a beautiful honeycomb reinforcement in it which I particularly liked, and it was rock solid!

[@ValkGame]

11:46 Yup, my dad made a robot arm to load metal plates for seat belt buckles into an injection molding machine for exactly that kind of thing, that was about 20 years ago.

[@a531016]

Phew! I'm glad I wasn't making it up! As a process it makes so much sense, I'm surprised I haven't come across it before?

[@karens.958]

Does anyone have a video/photo of the inside of Pioneer LD V2200? I’m trying to put one back together and could use a visual aid. It arrived to me in a dozen pieces so I’ve not seen it together. Thank you.

[@JasonTHutchinson]

The video is an analog signal, encoded in a digital format.

[@Watcher3223]

No, the main carrier is never encoded digitally in LaserDisc. The best description of how the pits and lands are laid out is in pulse width modulation.

[@JasonTHutchinson]

@@Watcher3223 the audio was digital.

[@Watcher3223]

@@JasonTHutchinson The original LaserVision specification never had digital audio; digital audio was added about six years after the format's introduction to market in 1978. And, the digital audio track is contained within an analog FM subcarrier at the 2 MHz band. Although LaserDisc did have digital signals, the basis of the format itself is analog; all digital signals had to be contained within analog carriers. And the video itself remained analog.

[@DanRamosDR]

I still have my working Denon Laserdisc player and a collection of perfectly working laserdiscs... including the non-altered original theatrical releases of all three original Star Wars films.

[@bradnoyes7955]

3:15 Not what I'd consider analog, but uncompressed digital, absolutely

[@DAVIDGREGORYKERR]

Video on vinyl was a RCA CED thing.

[@tbj84]

Just nailed it! Goldeneye for the win!

[@a531016]

If I was going to buy a disc - It was going to be a good one...

[@CthulhuSaves]

My Pioneer LD player was working fine when I had to put it into storage. It sat for a few years, and when I got it back out, it would power-up, but shut off when I would hit Play. Since I can't exactly look up a LD repairman in the phone book, I'd love to hear any ideas what the problem could be. I'm hoping it's just caked with dust inside, and maybe cleaning it would do the job. (I kept buying discs while it was stored, in anticipation of getting it out again. Hate to think I'll never be able to play these gems.)

[@a531016]

If I had to guess, I would say that either the optical carriadge or the spidle were seized up and need some lithium grease? I would think the over current of a motor stall is enough to trip the power supply? Pure guess work of course!

[@djlegenduk]

Old leaky capacitors are always a good first place to check. Any that are obviously leaking or bulging just replace with rated equivalent.

[@a531016]

@@djlegenduk Very good point! Probably should have lead with that! www.element14.com/community/docs/DOC-95798/l/the-electronics-inside-29-bbc-micro-recap

[@electronash]

I guess "digital" is really all about what the signal on a medium represents after the first layer of conversion. I would call it digital if the disk encodes 0s and 1s for a direct *binary* representation. On a Laserdisc, as you said, the pits and lands on the disk surface are actually of variable length, which encode the peaks and troughs of the original *analog* (and Frequency Modulated) signal. After low-pass filtering, it really is just an analog signal with a finite bandwidth limit. But, you can of course encode true digital (binary maths stuff) in an analog signal via some form of modulation or other mode. Which is how PCM and other digital stuff is encoded alongside the main video carrier. (they later added compressed 5.1 audio like Dolby Digital and DTS.) After demodulation, the digital audio on the disk directly represents binary 0s and 1s. I'd call it "mostly analog". lol

[@a531016]

I'm very interested to know, since the audio was PCM encoded, why they didn't encode the video too? I assume as you say, it's bandwidth related (PCM would need a much higher bit rate to recreate a wave) although it could be decoding power available at the time?

[@electronash]

​@@a531016 Yep, mainly the processing power needed at the time, I guess, and the added cost of high-speed ADCs etc. It was just "easier" to transfer the FM video signal onto the disk in a more direct fashion. With enough bandwidth for a certain number of video lines per field, vs an hour or so of runtime per side. (and getting Laserdisc to work reliably enough to mass-produce players for the public must have been hard enough.) Without any digital compression, the raw samples of a Composite signal would likely have taken up way more bandwidth than the 6 MHz that the analog video did. I don't think there was any equivalent to MPEG codec way back in the 70s. Even in the early 90s it was still quite expensive to buy an MPEG decoder card for VideoCDs etc. I remember it well. hehe

[@Watcher3223]

@@a531016 Digital video encoding for consumer products simply wasn't available back in the early 1970s when the LaserVision system was formally being developed by Philips and MCA Laboratories. At that time, high quality digital audio was only just starting to become available for professional/commercial use, so it would be a ways before digital video would have been developed, and then initially for professional/commercial applications like broadcast television, and then in service to analog TV standards like NTSC. And PCM audio on LaserDisc was never originally part of the LaserVision system as it was added on about six years after the first release of the system to the consumer market in 1978.

[@electronash]

@@Watcher3223 Yes. that's the main difference - the pits and lands are variable length, to directly represent an analog signal. But that's why I said *digital* is really more about what the an analog signal can be made to represent. CDs and DVDs differ because the pits and lands directly encode *binary* bits, so are more-or-less of equal lengths for the 0s and 1s. (which uses EFM and CIRC etc., but still basically digital on the disk itself.)

[@Watcher3223]

@@electronash DVD and CD have pits and lands that represent binary notation, but those formats use EFM (DVD uses EFM Plus) partly to ensure that the pit and track pattern is written in such a way that it can be tracked by the tracking and focus servo circuits for the optical pickup at all times the disc is being read. It also adds a level of resiliency against optical obstructions (dirt, dust, scratches) to further reduce the chance of mistracking. Once read off of the disc, the EFM encoded signal must be decoded to extract the original signal. CIRC is for error correction and is part of the decoding process. LaserVision does use EFM for digital audio, but that's primarily for helping to ensure signal integrity as its contained within an analog subcarrier.

[@DAVIDGREGORYKERR]

I would be very careful as the drive for the LASER in the PHILIPS LASERDISC player is in the region of 5-10KV

[@Crackalacking_Z]

The video wasn't compressed so picture quality was better than DVD. The physical size made them just very pricey, space consuming and inconvenient: something for movie enthusiasts. The mass market just used VHS tapes and then DVD.

[@stupossibleify]

I always assumed "Peritel" was the French equivalent of SCART

[@DAVIDGREGORYKERR]

I think the speed would be 1800RPM

[@beautifullworld8170]

Best

[@williamwilson480]

i own 3 LaserDisc players😁

[@a531016]

3 is impressive - I need to know the back story here... Is it because you have a karioke one, a high end Hi-Vision CAA version, and one for a bedroom?

[@williamwilson480]

no the first one is first ever US laserdisc player from 1981 is a top loader with coaxial cord to plug into tv the second one's from 1987 and my third one is from 1989 none of them are karaoke

[@a531016]

@@williamwilson480 That's a much better answer - I'd assume the 1981 model has the helium neon laser? Does it still work? If you ever part ways with it - I'd be interested to find out!

[@williamwilson480]

@@a531016 I'm not sure if it has a neon laser but it still works got it for $80 off of Craigslist back in 2019 the model was VP-1000

[@a531016]

@@williamwilson480 Wow - That is a machine with a very pleasing asthetic. I have just seen one on eBay for $1500!

[@msylvain59]

SCART is the worst plug design ever. Oversized contacts, but made from the cheapest tin metal with terribly poor tolerances. Several protocols on the same plugs, bringing a lot of compatibility problems. I don't even talk about the horrible bulky pure plastic frame and the ridiculous shielding piece. Re-using an existing plug design, like a Sub-D or a Centronics would have been a lot better....