Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371

[Vince]

[..]You can get iron-on real wood veneers and glue films these days that make finishing a lot easier than it used to be, particularly on small cabinets.
[..] You could always make 'composite' cabinets with MDF lining and real wood exterior though. The best of both worlds.
 

Hmm yes, forgot about that possibility. Not perfect as it would still be particle board inside, but at least from the outide it would be pleasing... or not, if the veneer is the kind that's so thin it come as a rooled sheet. If so, same problems as laminated plastic /false wood : the edges never look right, you can tell it's not plain/solid wood, and with time dirt gets between the edges and it shows more and more.. then the edges start peeling off and breaking into pieces, and the show is over.

From memory, in the golden ages of veneer in the 18th century in France, veneer was about 3mm thick (1/8") at the very least. It was more of a thin panel than a malleable thin sheet (which back then they probably would not industrial means of producing anyway, I guess...).
So I could make a particle structure covered in proper/thick veneer. This way the joints along the edges would look "propre", would not look fake, and would age well. Not falling apart or splitting apart.

Then you can try designing and building some serious speakers...  ]Then you can try designing and building some serious speakers... 

Yeah sounds like fun...

P.S. Yes, even with fine wood working skills, particle board (of one type or another) is better for speakers as it had excellent dimensional stability (you don't want movement and small gaps opening up with humidity changes. It also has higher mass and damping properties.

Gaps along the edges would be I would have thought, easy enough to fix, by depositing a bead of sealant inside the cabinet, all along the edges ?!

Picture looks "mionstruous"... 1kW speaker otr something ?! 

Is that one you made yourself, it's your home ?

[shakalnokturn]

I'd bet Gyro's speaker is lowish power with high efficiency, wasn't able to identify the woofer though.

The fuss about the crossover caps is I think mainly a question of Q factor and ESR. Of course electrolytics age more than others over time.
The Russian rectangular can paper-oil capacitors have a good reputation for crossover use in the audio world.

[Vince]

Wow, so now I need to learn Russian to be able to buy caps for my speakers... this is quickly getting out of hand !! 

 

[Gyro]

Hmm yes, forgot about that possibility. Not perfect as it would still be particle board inside, but at least from the outide it would be pleasing... or not, if the veneer is the kind that's so thin it come as a rooled sheet. If so, same problems as laminated plastic /false wood : the edges never look right, you can tell it's not plain/solid wood, and with time dirt gets between the edges and it shows more and more.. then the edges start peeling off and breaking into pieces, and the show is over.

From memory, in the golden ages of veneer in the 18th century in France, veneer was about 3mm thick (1/8") at the very least. It was more of a thin panel than a malleable thin sheet (which back then they probably would not industrial means of producing anyway, I guess...).
So I could make a particle structure covered in proper/thick veneer. This way the joints along the edges would look "propre", would not look fake, and would age well. Not falling apart or splitting apart.

No , veneer isn't what it used to be, unless you cut your own of course - not impossible for small cabinets I suppose, although the composite idea would probably be better for mitred joints (my veneer runs so that there is no visible joint where you would expect to see an exposed mitre). I did at least use a proper glue method rather than film or Iron-on.

Gaps along the edges would be I would have thought, easy enough to fix, by depositing a bead of sealant inside the cabinet, all along the edges ?!

True, real wood still doesn't have the same damping properties though, the long grain fibres make it resonant along the length, you could use extensive internal bracing though. Ply is another material that is used on some high quality speakers, that blends good rigidity and damping.

Picture looks "mionstruous"... 1kW speaker otr something ?! 

Is that one you made yourself, it's your home ?

Yes it is - and I made another one just like it. 

As shakalnokturn says, they are very efficient and very easy to drive. It's a fallacy that big speakers mean massive speakers (unless you're talking stadium PA stacks or something). I think the drivers are rated at 50W, but you'd never go there. Doing things efficiently means fewer compromises. In comparison, I think I read that the Boston M9s were rated at 130W (all RMS). To get the same output (volume and frequency response) from a small speaker means more losses, ultimately turning into heat, it's just physics.

I'd bet Gyro's speaker is lowish power with high efficiency, wasn't able to identify the woofer though.

The drivers are Tannoy 12" HPD dual concentrics (horn tweeter diaphragm in the rear, with the centre magnetic pole piece and cone forming the horn). I bought them for about £25 many years ago, needing new surrounds. Similar driver pairs go for around £1000 on ebay these days, out of my budget. I built the cabinets as tapered transmission lines rather than the traditional Tannoy bass reflex. I would have liked to go for one of their horn designs, but there's no way they would have fitted sensibly in the room! These are about as compact as you can sensibly go.

I built the Aluminium ribbon upper tweeters from scratch. I used Samarium Cobalt magnets from a big old server HDD (much easier with Neodymium these days). The ribbon came from Polystyrene capacitors, turned to length (ribbon width) in a lathe and then carefully unwrapped and corrugated between gear wheels.

The Russian rectangular can paper-oil capacitors have a good reputation for crossover use in the audio world.

Agreed, my crossovers are full of them! the round ones too. Excellent capacitors.


Sorry, I've taken the thread as far OT as you do Vince! 

[Vince]

Sorry, I've taken the thread as far OT as you do Vince! 

Well, no need to apologize, OT is where you discover people's talents and interesting unexpected stuff.
I now know you are very deep into audio, much more than I could ever imagine. So I know who to turn to for any audio stuff...
For local needs I have Shakal, he lives not too far away from me, IIRC... well, not at the other end of France anyway.
Maybe I should pay him a visit, bring my CD371 and CD's, so I can listen to them on some of his speakers, see how good it can sound. Then try my CDs on his modded old Philips to compare with my stock one.... I don't know.

You and Shakal should exchange e-mail addresses and marry each other. You seem to be on the same wavelength. Audio wavelength of course...  You would give birth to lots baby speakers and baby CD players and amps. I would pick some of them and grow them in my house.
Yeah sounds like a cool idea....

[Gyro]

Wow, so now I need to learn Russian to be able to buy caps for my speakers... this is quickly getting out of hand !! 

The stocks of former Soviet era military warehouse stuff available on ebay, from places like Ukraine, can be a treasure house of high spec parts. Obviously you need to be selective, but hermetically sealed components and things like valves (tubes) don't really care about spending decades in cold warehouses as long as they are kept dry. Some parts have long since become completely unobtainable new here, for instance large value polystyrene and Silver-Mica capacitors.

The output valves for my amplifier cost about £4 £6 each, compared to £100 or more for the more well known audiophile (not even audiophool) types, much more rugged too.  Of course, you need to design these things in, they're not just pin compatible (actually, some of the lower power ones are). Unfortunately, sellers have become more knowledgeable about what they have so prices have slowly climbed over the years, but there are still serious bargains, and it means that they are also able to include more information.

Haha, it sounds as if you do need Shakal near you, just to select the treasures from the trash in your ongoing acquisitions.   He's clearly very knowledgeable when it comes to audio!

[Vince]

Hmmm... sometimes you get lucky : went through my pile of CD players, to see what could be sold, what was working.... last week I put that Sony CDP-C305 5 disc changer for sale, at 40 Euros, just because I am daring. Market here is completely flooded with old CD players, so I expected never to sell it, or to sell it in 6 months once I had dropped the price progressively down to 15 euros max....

But, what do you know ? Less than a week after advertising it, I got a guy interested last night, saying he would come in person today ! And he DID show up ! Picked the player and did not even try to bargain me !    So, got my 40 Euros, in just a few days, truly unbelievable.

What's more : I of course let him play some CD's to see for himself that it was working fine. Said the sound was really nice on my Marantz speakers.... and he instantly spotted my pair of Technics speakers I had put in the background along the wall. Asked immediately if they were for sale !    Asked if he could listen to them. OK why not. I wired them in place of the Marantz. Played Bohemian Rhapsody as it's a nice song to test speakers, we agreed on that. Said they sounded nice, even if the Marantz were better.
Insisted again that he would be interested if I would sell them to him... said OK will do some research to see what would be a fair price, and get back to him soon. 

Technics SB-CS7  they are. Turns out there is quite a bit of info on these things, and a few for sale, so I was able to figure out what a decent price would be. More than I expected. I told the guy 80 Euros for the pair. Some sell them well above 100, other at 60... but he could listen to them and hear for himself that they were working fine. Buying them at 60 online then having to add 30 more Euros to package them properly and get them shipped, 90 Euros in all... and then you have absolutely no guarantee whatsoever that they will be in good shape/sound OK when you try them ! So 80 Euros for a pair that's local to him, no shipping, and he knows for a fact that they work fine... sounds a fair price to me. Waiting to hear back from him.

Also, he said he has a couple CD players that don't work, said he could not find anybody to fix them, so asked me if I would accept to have a look at them !

Hey, business is coming in fast !   

So, 40 Euros in just a few days for this player I paid only 5 Euros shipped for, and that I fixed in 30 minutes without even having to buy any part... excellent deal.

Guy was well impressed with my stack of 20 players and my 20 tube Tek scopes.

Sadly not many of my players are economically repairable. The few that do work are actually those that I want to keep, pfff...

I have a Philips CD824 (from 1990) which I like the design of. Seems to sell for a lot of money on Ebay, 85 at the cheapest, a couple at 120/125 Euros, and one at 280 Euros on offer.  Mine works fine, but the drawer is kaput, its gear shattered into pieces like glass. Think I might have found replacement kit (gear+ belt) on Ebay/China for under 5 Euros shipped. Of course I won't know for sure if the gear fits, until I have received it. In 6 months maybe... china stuff is cheap but always takes a month minimum to arrive, it's annoying...

If it works, then with a 5 Euros fix, I am good (paid 30 Euros for the player IIRC). If I can sell it for 100 Euros or so, that will be some easy money.
I will miss it as I like its design and keypad to get direct access to tracks, a neat feature as I find it painful doing long jumps on a CD. Have a CD I like with 19 tracks on it. Getting to track 19 directly is a time consuming and frustrating exercise on a normal player, as the player "stops" at every track along the way. Keypad is a revolution...
I don't know why they are so expensive... OK they have a swing arm, but crappy shitty looking CDM4/19. Nowhere near as sexy as my white CDM4/11 
DAC is.. not a TDA, but an "SAA" something...

Anyway, was nice meeting that guy, good quick business. Now here is hoping he will buy the Technics speakers ( = a quick buck and less clutter in the lab/living room) and pay me to fix his 2 broken CD players.

[Vince]

No haven't forgotten about the CD371... going to order the  shift register chip and some proto boards, want to experiment real soon with that...

[Gyro]

We're going to start charging you for advice!    It sounds as if you managed a good deal there.

The Philips CD824 has an SAA7321 Bitstream (delta sigma) DAC, you might want to compare and contrast with the TDA1541A models.  The gear wheel problem is common on Philips / Marantz players of a certain age - Philips used a lubricant that was incompatible with the plastic of the gear wheel, making it become brittle. I'm not sure when this became a problem, I've never experienced it on any of my players. I use a plastic grease for lubrication (Electrolube SPG*). The problem has led to a thriving market in new replacement gears though - it is getting easier to find them closer to home.

* RS and Farnell sell it, unfortunately TME don't.

[Vince]

[ Fixed 1,001 typos in previous message.... ]

The Philips CD824 has an SAA7321 Bitstream (delta sigma) DAC, you might want to compare and contrast with the TDA1541A models.

OK, will do as soon as I get its drawer fixed...

The gear wheel problem is common on Philips / Marantz players of a certain age
[..]The problem has led to a thriving market in new replacement gears though

Indeed, countless ads on Ebay China for replacement gears for the old Philips... but not so much luck for Sony players or more recent Philips Players.
Other than my CD824, have 4 Sony players and a recent Philips 5 disc changer, all in need of a gear here or there. None for sale 

- Philips used a lubricant that was incompatible with the plastic of the gear wheel, making it become brittle.

Ah, thanks for the explanation, explains indeed why there is such a market for these players nowadays...

I've never experienced it on any of my players.

Wow, lucky you ! Have only 20 players yet no less than 6 of them have a problem with one gear or another ! 

I use a plastic grease for lubrication (Electrolube SPG*). RS and Farnell sell it, unfortunately TME don't.

Thanks for the ref, was going to ask. Need to get some of that stuff now that I work on old consumer stuff....
Too bad TME don't have it, was gonna order from them for the shift register as way cheaper there.... 

[Vince]

What do you know ! I received the replacement gear today !  Took only 2 weeks to arrive, faster than in PRE-covid times, go figure ! 

The Philips CD824 now works ! 
Drawer makes a horrible noise though... not sure if it's due to crappy Chinese tolerances, or the total lack of grease on that gear since it's brand new, or the fact that everywhere I look in the drawer mechanism, all I can see is dark brown, bone dry, rock hard grease... need to clean all that, and empty a bucket of fresh plastic grease everywhere. Gonna order some...
Other contributing factor I suspect, is the mechanical design itself ?! I mean, the gear is very wobbly. It simply snaps into a recess, it's very loose to begin with. Very cheap and shitty design if you ask me ! 

In contrast, in my Technics players which feature the same CDM4/19 and drawer mechanism, it's much better designed I find : the gear is the same, but mounted in a different way : does not snap into plastic recesses. Instead, like you would a gear in normal times.. it's mounted onto a beefy metallic shaft. Gear is perfectly guided, zero wobble, zero play... just spins smoothly, perfect.

Another cheap looking thing on CD824, I find, is the shiny black finish of the drawer bezel. Makes it look very cheap/plasticky, and also looks out of place compared to the rest of the front panel that's flat black (which is what I like personally. Hate shiny finishes). They also placed the "OPEN" button on the drawer bezel itself ! Looks weird, and ergonomics is poor, especially when you want to CLOSE the bloody drawer. There is no" CLOSE " button... Pushing the "OPEN" button again does nothing. So either you have to brute force the drawer and push on it to force it to close, or you pressed the "PLAY" button, which again ergonomics wise is poor : what if I just want to load the CD and its TOC, but not start playing right away ? Can't do that.

So really, to me at least, it appears every aspect of the drawer thing, is poorly designed and implemented in this player... it's my biggest gripe with this player.

OK, so now it works, so let's test it against a TDA1541. The CD371 has its guts all over the shop right now, so instead I pulled the Toshiba.
Stacked the Toshiba on top of the CD824. Powered both players with their own power cable. This way I can swap from one player to the other, as fast as humanly possible : play a song, stop player, retrieve CD, open drawer of next player, press PLAY, and while it's loading the song, hurry to switch the audio cable at the back of the players.  It's the best I could figure out to minimize waiting time between hearings. To make it faster/better, I could buy another audio cable so that both players are wired at the same time, and I have only to press a button on the amp to instantly switch the source. Would also need to make a copy of the test CD so that I can have the same audio CD in both players at the same time. This way I won't have to swap discs. I can just preselect the song on both players, press PAUSE on the second player. Then once I am finished listening to a song on the first player, I can just press PLAY on the second player, press the corresponding source button/selector switch on the amp, and that's it !  This way, I guess I can have a very tiny dead time between hearings. Like a coupe seconds. Would need to rip a few CD's in a lossless format like FLAC, I guess ?  Of course I have already my entire collection of CD's on my computer, but back when I ripped them all, was like 20 years ago IIRC. Back then my computer didn't have quite enough storage capacity to contemplate FLAC, so instead I compressed using OGG, because 20 years ago they said OGG was better than MP3, IIRC...
Just checked, I ripped them back in the day in OGG 160kbps.  A 4 minutes track weighs about 5MB.

Anyway. So I first listened to the CD824 then the Toshiba.
Again, I am not qualified to talk about audio, so just my personal feelings with my personal unofficial vocabulary, sorry it that makes no sense to anybody.
We are close to audiophool territory so arm your BS detector as well 

OK now that all due precautions have been taken... here is what I thought :

At first, thought it sounded super nice, was surprised. then after a few minutes I analyzed my feelings and figured it felt like it was a bit hollow, and like it was applying some artificial digital special effects to the sound, that made it sound attractive at first, but in retrospect felt unnatural. Felt like a Hollywood movie : lots of action, special effects by the pallet, you get attracted to it like a sweet/candy, and enjoy it while the movie lasts but you know it's just cheap emotions, you know it's not real, it's all fake and overdone.

Then I rushed as fast as I could to swap the CD into the Toshiba. Sound felt less spectacular, but more natural, the music and the singer voice sound more real, and more present, like they were in your living room playing and singing live. Provided more emotions, real ones, not fake.
Played a few of my favorite tracks from Daniel Balavoine : " Tous les cris les SOS" , " Le blues est blanc " , "Un enfant assis attend la pluie", and the Toshiba gives a shiver down the spine and brings a tear to the eye. I know, I am too soft, I know...

At the end of the day I guess it doesn't make much sense to pretend that one DAC is "better" or "worse" than another... it just depends on what type of music you like to listen to, and your personal preferences.. it's like for girls or cars...


Searched ebay for decent proto boards locally so I can get fast shipping compared to China. Found that ad :

https://www.ebay.fr/itm/164167899811?hash=item26392b5aa3:g:N6QAAOSwFpNc9Mkc

2,50 Euros for a set of 4 FR4 board of varied dimensions. The largest one looks like it would be just large enough to accommodate the DIP version of the shift register along one of the long edges, taking about one half of the board, and the other half would be enough space I think to fit the 7 segment LED displays.
The other boards I can reuse for whatever other project later, not a waste.

Shipping is about 4.50, twice as much as the board, but well that's the price to pay for local/fast shipping...
Might buy some from China as well so that I can have a larger stock for cheap. China also gives more choices, I can get larger boards there:

https://www.ebay.fr/itm/183544234631

[Gyro]

Congratulations, you have a good ear (and not in an audiophool way). That's a very good summary of the difference between the TDA1541A and later Bitstream players. The Bitstream ones are very 'in your face' - immediately impressive, but lacking in subtly. It's a bit like 'Shop mode' on TVs, it makes the colour more vivid so that the TV stands out in the store, but you would be uncomfortable using this setting normally. Given that you are listening to the Toshiiba in it's original stock mode, with no improvements, your experience is hopeful.

One problem with the Bitstream DACs is that Philips integrated everything on-chip, including the audio opamps, which are not of the greatest quality as it is a mostly digital chip fab process, and you can't get around them. All sigma delta DACs need noise shaping etc to work though. The TDA1541A, by contrast gives you the direct output of the bit current switches, making it much more possible to optimise the analogue filtering and output design, as you will see in Arcam players for instance (compared to the standard Philips reference design) - it would be nice to see the actual Toshiba schematic.

Your photo shows what I mentioned about the mechanics of the later players - that web structure of plastic, holding the drawer motor, slotted-in gear etc. This makes it impossible to keep the transport and loading mechanism as single unit, they are completely tied into the case moulding. Yes, noisier drawers are normal.

The display is nice though - it makes the player look more expensive. The differentiation on these players is all down to styling, display and number of buttons with maybe the s-pdif output populated on some models.

Hopefully you can see the value of the CD371 as a basis for a project (whilst enjoying the Toshiba). 


P.S. Did you ever post a picture of the Toshiba PCB? I can't remember.

[Vince]

Congratulations, you have a good ear (and not in an audiophool way). That's a very good summary of the difference between the TDA1541A and later Bitstream players.

Wow, I am stunned ! I can't believe that I managed to convey something worthwhile with my word salad, especially given my total ignorance of the appropriate terminology, not to mention the language barrier of course, being a Frog.  Either I got very lucky, or YOU have a talent for making sense of my salad. You must a very selective / High Q filter taht's able to discern a faint signal lost in an ocean of noise. Gyro is one hell of a fine piece of lab equipment !

The Bitstream ones are very 'in your face' - immediately impressive, but lacking in subtly. It's a bit like 'Shop mode' on TVs, it makes the colour more vivid so that the TV stands out in the store, but you would be uncomfortable using this setting normally. Given that you are listening to the Toshiiba in it's original stock mode, with no improvements, your experience is hopeful.

Sounds better and much more concise when it's you telling it ! 
Good analogy with the TV ! 

One problem with the Bitstream DACs is that Philips integrated everything on-chip, including the audio opamps, which are not of the greatest quality as it is a mostly digital chip fab process, and you can't get around them. All sigma delta DACs need noise shaping etc to work though. The TDA1541A, by contrast gives you the direct output of the bit current switches, making it much more possible to optimise the analogue filtering and output design, as you will see in Arcam players for instance (compared to the standard Philips reference design) -]One problem with the Bitstream DACs is that Philips integrated everything on-chip, including the audio opamps, which are not of the greatest quality as it is a mostly digital chip fab process, and you can't get around them. All sigma delta DACs need noise shaping etc to work though. The TDA1541A, by contrast gives you the direct output of the bit current switches, making it much more possible to optimise the analogue filtering and output design, as you will see in Arcam players for instance (compared to the standard Philips reference design) -

Wow, very interesting indeed ! Thanks for that.  Cold technical/engineering fact, that hold water, that actually make sense...the anti-thesis of audiophoolery that's religious-like, faith-based tales that spread like a virus and can never be killed.

Nice to see that even though enjoying audio is very much an irrational / subjective feeling, there are none the less some actual technical reasons that can put some sense in that picture, and I enjoy every bit of such information, keep it coming !!! 

it would be nice to see the actual Toshiba schematic.

At first I didn't want to spend the 5 bucks websites wanted for the service manual, both out of principles (in 2021, paying for a 30 year old schematic... really ?! Who does that ! ), and also because it would eat a good chunck of any profit margin I could hope for, when reselling the player. But that was back when I got it. Now is different... I know I will keep that player, it's my baby.. so, spending 5 mere Euros to get to learn its guts in detail, sounds like cheap and worthwhile. So I think I will cough the 5 Euros....

The display is nice though - it makes the player look more expensive. The differentiation on these players is all down to styling, display and number of buttons with maybe the s-pdif output populated on some models.

Yep, all show and no go as they say !     Almost got me ! ... but looking at the thing in detail and in an objective manner... freed me. Now I am "ready" to sell it, and hopefully quite a good profit in the process, seeing for how cheap I got it and how much it seems to fetch on Ebay !

Hopefully you can see the value of the CD371 as a basis for a project (whilst enjoying the Toshiba). 

Yes. The CD371 is indeed a good candidate. I mean all the mods are clearly documented for it, by Shakal at least how did it on his. Plus, the poor thing is already going to be butchered in order to work around the unrepairable stock LED display module... so I would rather not butcher both players ! 
Prefer to keep the Toshiba stock and fiddle with the CD371. This way I can also use the Toshiba as reference when assessing mods I do to the CD371. I will always have a stock 1541A to come back to when needed, when I want to.



[quote}P.S. Did you ever post a picture of the Toshiba PCB? I can't remember.[/quote]

Yep I did, a while back. You looked at it and figured it must be based on CD473 board, if just based on the odd placement of the DAC, far away from the final op-amps. You also said that it was not, though, a C473 board since one of the big chips was unpopulated on the Toshiba : the one in the very bottom right corner of the PCB. Said it was an EEPROM used to store data to implement the "FTS3/ favorite tracks feature, which the CD473 has, but the Toshiba doesn't have.

I just looked at the board view of schematics in the CD473 manual, indeed it appears to confirm all that you said. Same layout ads the CD473 with just the EEPROM unpopulated.

Would still buy the Toshiba manual anyway, to be 100% sure of every details of the schematic, and get the Toshiba specific parts, like the front panel stuff.

Attaching again the Toshiba main board picture, to keep you from having to rewind this thread....


Went to order the shift register on TME.... TOO LATE, now says out of stock, and adding to boot "WARNING : HARD TO GET !!! "   
Should have hurried. So now back to Farnell, where it's much more expensive.. that's life. Well at least I get to buy the  plastic grease, so it's not all bad. That stuff must be made of solid platinum : 20 Euros for a 30cc syringe, REALLY ?!   
In all fairness, given how sparingly the stuff is meant to be used, even that 30cc syringe will probably outlive me !

[Gyro]

Thanks for the compliments! 

Ah yes, I remember now - the depopulated 473, stock Philips PCB. In that case there's no need to spend the 5 bucks, we know what the schematic is. We also know that Toshiba didn't do anything special to achieve the sound - that's a good thing!


P.S. Shame about TME, at least buying it and the grease (and a few other bits?) might get you past the free shipping threshold, which should offset the difference in cost. Yes 30cc goes a very long way!

P.P.S. The front panel will be using the standard CD473 I2C interface. Philips might have done a custom micro for their keys / display but very possibly not. It's easy the reverse engineer the buttons anyway.

P.P.P.S ( ) I just noticed one small difference in your photo - Toshiba used a crystal for the microcontroller clock rather than a ceramic resonator (stock Philips). Potentially one less source of jitter superimposed on the GND / +5V supply rail relative to the transport clock? I don't know, but it cost them a little extra to do that, interesting.

[Vince]

P.S. Shame about TME, at least buying it and the grease (and a few other bits?) might get you past the free shipping threshold, which should offset the difference in cost.

Yep I do need a few other bits and bob for a tiny design project for a friend, long overdue.
However it shouldn't be needed to get passed the threshold at all. Haven't ordered anything from Farnell in a very long while (2+ years ?....) due to my house move fiasco, but IIRC threshold to get free shipping is only 15 Euros (before tax I think). In other words, ordering the grease ALONE is enough to get free shipping ! 

Yes, you are right, free shipping at Farnell means I get to save 8 Euros over TME, since their shipping fee never goes away.
So that more than offsets the silly price difference on the register chip. So it's not that bad ordering from Farnell in the end, I guess.

Will complete my order tomorrow. For now..... 

[Vince]

OK, some display action ! 

Since that guy on that website implied that he managed to salvage the original display, I gave it a try. I assumed it must be surface mounted, so I applied some heat at the back of the PCB with the hot air station, see what that would do. Nothing, won't come off.

Turns out it's not soldered to the PCB ! The "display" that we see is in fact a mere bit of plastic, held by 3 pegs that are heat welded at the back of the PCB. I snapped them off with a sharp blade, and the "display" came off instantly, no drama.

The LEDs are not part of the plastic housing.. they are completely separate, soldered directly to the PCB, as individual LEDs. The LEDs themselves aren't even packaged as such. They are just bare dies bonded  directly to the gold plated tracks on the PCB. I took a macro shot of the dies, you can clearly see the tiny fragile bonding "wires" that connect the anode of the die to the golden trace on the PCB, the common anode trace. Like it were an integrated circuit... looks so cool, I so wish I could afford a decent microscope with a camera, to take much better shots of this. No, no USB "microscope" for me, want an actual stereo microscope with a port for a camera.

I tested all the LEDs with my DMM... some of them won't work. So can't reuse it. Would not have been fun anyway, trying to reuse the existing PCB with its routing... So next best thing I guess is make my own PCB and solder tiny SMD LEDs. Well, that's were I would really need a microscope then ! 
Aligning so many so tiny packages would not be possible with a naked eye. Not with MY eyes at any rate, don't know about yours...

Problem : a bare die can just about fit inside the "slots" in the plastic housing.. but a PACKAGED LED hmmm... not sure there exists an SMD LED with a package so tiny that it would fit in the existing slots.... 
I tried to eye ball the dimensions of the slots with my calipers. I would say they measure about 3x1mm.  So I would need a package that's smaller than that, so I can be sure it will fit, even if I don't get the alignment perfect, which of course I won't.

Failing all that, I guess I can try to find a replacement display, like people did on that other website. Sadly the shape of the segments of the display they came up with, is different, and I don't like it. Will see what I can find on Farnell website.... if I can't find anything, never mind. Would still complete my order and use displays I have in stock, even though they are 4 times larger. Still good enough to go past the proof of concept stage.... if successful then I can worry about finding an appropriate display.

Anyway... making some progress at least....

[Gyro]

Ah yes, I maybe should have pointed out that the LEDs would by chip-on-board with bond wires. A lot of LED displays are (/were) done the same way. If all the bond wires are visibly intact, then it may be that the output pins of the chip on the back are shorting them. The actual diode test voltage reading on the DMM will tell you.

I think I mentioned before that there are replacement display PCBs on ebay that re-use the existing plastic part, so there ought to be enough space for modern SMD LEDs. Here's an example (see the description and second picture)...

https://www.ebay.co.uk/itm/294024117929

[Vince]

Thanks for the link ! Exactly what I need then !    SMD LEDs already soldered perfectly aligned, PCB already done, cane re-use my existing housing for a perfectly OEM look... 27.50 Euros + 10 Euros shipping, 37.50 Euros for a perfect solution with zero R&D and production cost, turn key solution...  it' s a no brainer.

Still, for the fun of it, I would still like to cobble quick and dirty proof of concept with a DIP package and proto board and whatever LED display I have on hand... then when I am done with the fun part, I will just order that PCB on Ebay to get the bloody player fixed quickly and properly, and move on to the gazillion other things that I have to do.

[tautech]

16x 0603 LED's and possibly a little work with a Dremel might save you ~30 Euro. 

[Gyro]

Thanks for the link ! Exactly what I need then !    SMD LEDs already soldered perfectly aligned, PCB already done, cane re-use my existing housing for a perfectly OEM look... 27.50 Euros + 10 Euros shipping, 37.50 Euros for a perfect solution with zero R&D and production cost, turn key solution...  it' s a no brainer.

Still, for the fun of it, I would still like to cobble quick and dirty proof of concept with a DIP package and proto board and whatever LED display I have on hand... then when I am done with the fun part, I will just order that PCB on Ebay to get the bloody player fixed quickly and properly, and move on to the gazillion other things that I have to do.

Ah ok, I was thinking that you would choke at the price (still half the price of a potentially unreliable NOS display though).

You might want to use this other link instead as it specifically states MM4202A (same seller)....  https://www.ebay.co.uk/itm/294024117929


P.S. The proof of concept display will be good if you decide on the 'project' approach in a more substantial cabinet. You could do things like bigger digits for the Track vs Index digits (Minutes / seconds in time mode). Also having a choice of display colour. I notice that the ebay display has the option of Red LEDs too.

[Gyro]

16x 0603 LED's and possibly a little work with a Dremel might save you ~30 Euro. 

Yes, that is certainly an alternative solution. Earlier in the thread we were discussing the MM5450 IC which provides the logic functionality (the MM4202A display is intelligent) allowing the choice of any common anode 7 segment displays. The cost of the IC needs to be factored in.


EDIT: I'm not sure whether anyone has ever figured out whether it is the COB driver IC or the LED dies themselves that fail in these old displays (presumably the former in this case as it didn't light any segments).

[Vince]

16x 0603 LED's and possibly a little work with a Dremel might save you ~30 Euro. 

THe problme is the chip not the LEDs... the bonds inside the big black blob are intermittent, I can't fix that. Replacing the few dead LED's I (probably) fuckd up when handling the module after I had removed the plastic housing, will not fix the chip...

Need a new PCB with a replacement chip. That means R&D costs and time, messing with tiny LEDs to ling them up, don't have a microscope etc. Once you factor everything in, 37.50 Euros for a turnkey perfect solution, is fucking CHEAP !!!     There is no way I could come up with the same product for less money, and all the time spent doing it is priceless too, I have fucking a millions other things to do ! 
No no... Nooooooo 37.5 Euros is a life saver !   Plus, it's not ending up in some chinese ebay seller, instead it goes to some Philips CD player enthusiasts in the Netherlands who took the time to do all the work and bothers selling it on ebay to help others. I am more than happy supporting that kind of people.

I have plenty of other custom design projects to spend my time and money on, don't worry  !     
This module just isn't one of them...

[Vince]

Ah ok, I was thinking that you would choke at the price (still half the price of a potentially unreliable NOS display though).

It's a total no brainer, one would have to be a fool to think he can  come up with the same product for much cheaper, for a one off, unless he does not count his time or much anything really. I am old  enough now that I am starting to value TIME much more than I did 20 years ago, for sure...

You might want to use this other link instead as it specifically states MM4202A (same seller)....  https://www.ebay.co.uk/itm/294024117929

Exact same link / ad that you posted earlier !     You got it right the first time 

P.S. The proof of concept display will be good if you decide on the 'project' approach in a more substantial cabinet. You could do things like bigger digits for the Track vs Index digits (Minutes / seconds in time mode). Also having a choice of display colour. I notice that the ebay display has the option of Red LEDs too.

Nope I don't fancy spending time and money doing my own cabinet, which would look amateur and junk at best, I guess.... however I sure am disappointed that CD players manufacturers, no matter how high-end, all had cheap crap chassis and front panels. None of the billions of CD players that hav come to exist meet my expectations, how ever basic they are. The quality factor of the cabinet hardly ever matched the quality of the audio. Cabinet was always an afterthought it seems. EIther that, or doing a decent cabinet would cost so much in material and tooling that the final price of the product would be staggering  even for a high-end player, and nobody would have bought them...

Anyway, even though I won't be making a custom cabinet, I still want some quick fun cobbling together a DIP package shift register on a proto board. Not  costing much, not going to take much time at all.. just some quick cheap fun, then move on to the next problem ! 

Only custom things I seriously envisage as I said earlier, would be customs speakers with a home made / custom wooden cabinet, so I can have speakers I actually enjoy looking at as well as listen to.

[shakalnokturn]

You should start looking for a Studer / Revox CD player.
You're not going to like the price though...

[Gyro]

You should start looking for a Studer / Revox CD player.

Aren't we all! 


Edit: Actually, looking at the Studer A727 service manual, the post-TDA1541 I/V and analogue filter circuit (fixed level output) is pretty much identical to the Philips CD371! Likewise the Revox B226. The devil is all in the detail - PSU rails, grounding etc.