EEVblog #863 - World's First Portable CD Player Teardown - Sony D50 - Page 1
Forum section: electronics / general

author: EEVblog
author_rank: Unknown
timestamp: March 28, 2016, 11:34:47 pm
content: What's inside the world's first portable CD player, the Sony D-50 (D-5) ?1984 vintage!Also a look at the laser beam splitter optics, and the gorgeous service manual.Service Manual:http://www.minidisc.org/manuals/sony/service/sony_ZS-D5_service_manual.pdfNobutoshi Kiharahttps://en.wikipedia.org/wiki/Nobutoshi_KiharaMC Frontalot Zero Day Album:http://frontalot.com/index.php/?page=cd4

author: Brumby
author_rank: Unknown
timestamp: March 29, 2016, 12:30:53 am
content: Great video. Some amazing innovation considering the time - but we all came to expect that sort of thing from Sony.My personal favourite was that service manual. I've never seen one that comprehensive - and there was enough information for me to tackle it with a high degree of confidence - even though I've never opened one up before. Truly commendable effort.

author: MarvinTheMartian
author_rank: Frequent Contributor
timestamp: March 29, 2016, 12:58:39 am
content: Quote from: Brumby on March 29, 2016, 12:30:53 amAgree, a very impressive manual.Don't know that much technical stuff as yet but with that amount of detail I would give a repair a go!

author: retrolefty
author_rank: Super Contributor
timestamp: March 29, 2016, 01:08:15 am
content: Great tear-down Dave, thanks.I owned a new D-5 as a Christmas present when the price dropped to around $125 as I recall. Never had a need to tear into it and gave it to my sister in the mid-90s as I recalled. I only replaced it because I wanted to be able to burn CDs so a recorder/player two disc unit took it's place.Other Sony products I still own are some great stereo hi-fi products from the 70s:TA-2000F preamphttp://www.thevintageknob.org/sony-TA-2000F.htmlTA-3200F amphttp://www.thevintageknob.org/sony-TA-3200F.html

author: Synthetase
author_rank: Regular Contributor
timestamp: March 29, 2016, 02:07:28 am
content: I used to own a Philips one like this. Also made in the mid 80s, slightly more integrated than this one, it had a single sided board. Like this, it could be powered by 9V jack, but also had a compartment for 6xAA cells. It also featured line out, two headphone sockets and the control buttons and LCD display were very similar to the Sony. No anti-skipping buffer either - the disc itself was not clipped to the rotor like modern players do, but relied on gravity to hold it to the spindle. One of the fun things to do with old CD players like these was to put data discs into them, because they didn't check to see if they were music discs before commencing playback.

author: n3vti
author_rank: Contributor
timestamp: March 29, 2016, 02:17:55 am
content: Wow, talk about schematic porn in the video... they just don't make them like they used to. Oldest CD player I own is from about 1992 and still works. I think it's a Sony as well.

author: Don Hills
author_rank: Regular Contributor
timestamp: March 29, 2016, 07:07:53 am
content: A few points:- The service manual you linked to is not for the D50 discman - it's for a boom box style Minidisc player/recorder. I found the right manual at Electrotanya, it might be on other sites too.- The large metal cover is over the analogue DAC stages, including the reconstruction filters (Lowpass filters) which are mounted on a daughterboard under the can. They appear to be LC filters, you can see the inductors on the board layout diagram. You couldn't use a digital filter with these original non-oversampling DACs, it had to be done with sharp cut-off analogue filters.- I built a soldering iron temperature "controller" similar to the one shown, with a bypass switch for the diode for large jobs. It brings the temp of my Antex irons down to a good range for delicate work and doesn't burn the tinning off the tips.

author: coppice
author_rank: Super Contributor
timestamp: March 29, 2016, 08:16:21 am
content: Quote from: Don Hills on March 29, 2016, 07:07:53 amBefore sigma-delta DACS it was pretty common practice to use a digital filter to over-sample by a factor of 8, and run the DAC at the higher sample rate. That simplified the analogue filter.

author: funkyant
author_rank: Unknown
timestamp: March 29, 2016, 09:47:48 am
content: It was nice to see you're appreciation of the service manualI did start a thread about this a while ago, but it didn't gain much traction:https://www.eevblog.com/forum/chat/beautiful-service-manuals/msg690885/#msg690885

author: bktemp
author_rank: Super Contributor
timestamp: March 29, 2016, 11:58:36 am
content: Quote from: coppice on March 29, 2016, 08:16:21 amDid they exist (as a single chip solution that would fit into a portable device) in 1984? There were some single chip digital oversampling filters from Yamaha like the YM3434 and YM3433 but the datecodes I could find were from the late 80th and early 90th.I don't know if there were other ones available earlier.

author: coppice
author_rank: Super Contributor
timestamp: March 29, 2016, 12:08:00 pm
content: Quote from: bktemp on March 29, 2016, 11:58:36 amThe earliest CD players only had a single 14 bit DAC, but it was fast enough to be muxed to do left and right, and run at 4x oversampling or more. I am not sure when 8x oversampling became common.

author: German_EE
author_rank: Super Contributor
timestamp: March 29, 2016, 05:42:33 pm
content: It's sad to compare the level of detail in that service manual with what happens now. Last year I tried to repair a Philips MP3 player and I contacted their 'service center' for a copy of the technical manual. Nothing was available, if the unit breaks under warranty then the dealer is expected to throw it away and give a new unit to the customer free of charge.That service manual from Sony was so good I could probably build a new CD player from a pile of parts.

author: DimitriP
author_rank: Super Contributor
timestamp: March 29, 2016, 06:29:13 pm
content: These were nice. I hope to find another working one someday. I miss mine.

author: Towger
author_rank: Super Contributor
timestamp: March 29, 2016, 07:13:51 pm
content: Obviously I am too young to be allow to watch:

author: SeanB
author_rank: Super Contributor
timestamp: March 29, 2016, 07:49:12 pm
content: That manual was produced the old fashioned way, using large sheets of white board, with the typewritten sections cut and pasted onto them, using glue to hold them down in position. Circuit diagrams hand drawn by a draughtsman on a large sheet of vellum paper, in pencil, then darkened with a Rotring pen afterwards to get the final diagram. The red was done with an acetate sheet overlay, which had the drawings made on it using a black Rotring pen, and a diagram on tracing paper placed under it, so you could see the placement to copy faithfully.Then the final draft was signed off, and carefully placed in an exposure unit ( around 2m by 1m, using 2 1kW linear halogen lamps for light) and used to make a final lithographic film master. The developed film was then carefully checked again, to ensure that the halftones were right ( a woven screen used during exposure to make dots) and sent finally as a set of positives to the printer.There they used these to make the final aluminium plates, and then printed the manual on the final paper using an offset press. Colour was done with a second print head, which printed the red ink on the page at the same time as the black, using the blanket to transfer the image. Big press for the long pages, using part of a very wide press, and doing all the other pages as sections along the wide paper. To print double sided simply turn over and print again, using talcum powder to keep the ink layers from sticking or transferring to the other pages. Then slit to size, collate and fold using a folding machine. Finally put the whole lot together and bind, then a final trim.Bleeding expensive for a short press run, the costs of the plates are high, and the set up of the press is only doable with an experienced printer. You really want to print more than 10 000 copies to get the cost down, though I think Sony was able, because of the worldwide service centre network they had, to get to this level with ease.The final print run for this would take a pressman around 3 days to run, and consider that the same job with 100 000 copies would also take the same time, with a lot less wasted paper in setup. You typically budget 1000 sheets for setup, as you lose a good number in initial alignment, then a few in setting the second colour, a few in the reverse side, a few in setting the slitter, a few in the folder and collation and the last bit in the binder, though the reject sheets often can be used in set up further down the line if one side or colour is correct. Your print order will be 10 000, plus a few dozen to a few hundred extras, depending on the printmaster and how experienced he is in setting up his press.Yes I was a machine minder at times, running an offset press on occasion. Printmaster is now retired and we no longer do in house printing, external press for the few jobs that laser will not do as well. I got good at doing business cards and making scratch pads from the reject sheets, those that were not used as press cleaning sheets though, as they came out solid colour.

author: ftonello
author_rank: Contributor
timestamp: March 29, 2016, 09:10:32 pm
content: Awesome video and service manual!!! Miss my D-121. Miss the 80's - 90's...but the world goes one! Is a fact that can,t not live without my mp3 collection... No matter were they are played... Ipod, cloud, online, pendrive at my car player...even on my old cd,s!!!!

author: kalleboo
author_rank: Regular Contributor
timestamp: March 30, 2016, 07:41:28 am
content: Quote from: German_EE on March 29, 2016, 05:42:33 pmI guess it's not unexpected when the cost of manufacturing is so low, and the cost of skilled labor is so high. I wonder if repairs could be made profitable if they shipped stuff off to China? Presumably that's where stuff gets "refurbished"?Considering the increasing ecological impact, I wouldn't be surprised if one day more forward-looking governments in places like Europe would mandate a certain level of repairability (at the very least things like replaceable batteries, LCD displays)

author: Halcyon
author_rank: Unknown
timestamp: March 30, 2016, 07:42:01 am
content: Quote from: Towger on March 29, 2016, 07:13:51 pmLog out of YouTube and just view it as a "guest".

author: rsjsouza
author_rank: Super Contributor
timestamp: March 31, 2016, 01:33:47 pm
content: Great trip down the memory lane, Dave. Thanks! I still remember a friend with one of the very early desk based CD players - it was very similar to the famous CDP-101, thus I can't tell with absolute certainty it was.Quote from: SeanB on March 29, 2016, 07:49:12 pmThat is a term I don't hear in a loooooong time...BTW, I still occasionally use a portable CD player, but amore modern model from Philipswhich even plays CDs with MP3 files!

author: Shred
author_rank: Contributor
timestamp: April 02, 2016, 07:18:58 am
content: I still have my D-50 - it's no longer working, but is still in the original box. I also have the service manual for it - and service manuals of similar quality for a couple of other 80s vintage Sony audio devices.I had the external battery case for the D-50 and the one thing I remember about it was that it burned up 6 x C cell at an alarming rate. I was amazed to buy a 2005 era Sony CD player and find that it could run for 70 hours on a pair of AA cells. (For the record: it cheats - spin the CD up, read a few minutes of audio in to a big RAM buffer, then put the motor to sleep).

author: pelule
author_rank: Frequent Contributor
timestamp: April 04, 2016, 08:17:53 pm
content: I am the proud user of the next generation of Sony CD-?. I bought it in 1988 at a sharper image shop in the US.It has nearly same operation, just a bit lower iin height and has a NiCd Accu for a real portable usage (max. 30 minutes)It is still working great and does read also bad CDs, the modern CD player do not accept anymore.It's quality is just beaten by the 1st CD-Player from Philips, I am proud to have also. This real heavy puppy is also working great and in a just like new shape.If anyone has interest, I may publish some pirtures.PeLuLe

author: linux-works
author_rank: Super Contributor
timestamp: April 04, 2016, 09:43:47 pm
content: playing into an 'anti skip' buffer made me think of the tale of 'audio ram'. wonder if anyone can confirm its true or a hoax.the story goes; that early on in portable cd players, ram was expensive. computer ram had to be perfect but what do you do with ram that had a few bit errors? use it for audio! lolI think the lore is that the error correction can be made to 'fix' bad bits in bad memory, as long as its not too bad. sounds almost plausable and many people reported that the anti skip feature on some old cd players made the sound worse. it could have been the error correction trying to mute or mask tiny bit errors.again, it makes sense since ram in the 90's was VERY expensive and if there was ANY way to reuse bad parts, they'd have done it.and so, the term 'audio grade ram' was born. again, that's the story I've heard but have not been able to confirm it for actual fact.(fwiw, this sony predates all of that since there was no 'read into buffer' back then; it was all realtime reading with very little buffering at all).

author: pelule
author_rank: Frequent Contributor
timestamp: April 04, 2016, 09:47:03 pm
content: Just checked the products: Sony portable Discman D-10, Philips CD-Player CD-101PeLuLe

author: coppice
author_rank: Super Contributor
timestamp: April 06, 2016, 12:40:20 am
content: Quote from: linux-works on April 04, 2016, 09:43:47 pmAudio DRAM, or ARAM, was real. It was used in various applications where it was easy to map out a few bad rows, or just live with some bit errors. Some devices were supplied with a guarantee that a few specific rows could be relied upon, where you could store an index of the good and bad rows in the rest of the device. The boot up process included a few seconds to map the flaws in the device, and build the row index table.In most uses ARAM provided a flawless buffer, but one of slightly indeterminate size. ARAMs were used for digital answering machines, and a variety of other digital audio applications, but it was an odd market. Instead of DRAM makers being eager to get value out of their imperfect chips, they were very concerned that shipping partially defective devices might affect their reputation for high quality. So, you didn't see these things proudly listed in a manufacturer's catalogue. You had to work through contacts.