Author Topic: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371  (Read 4736 times)

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Offline Vince

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #50 on: April 19, 2021, 05:55:11 pm »
Due to a rebellion among my Patreon supporters, I decided to unveil the next episode much earlier than I originally meant to. So here goes :

What does the white CDM when it runs in the Toshiba ? Place your bets, I'll come back in 5 minutes.......

[5 minutes later]

So... what does it do.... it does... it does.....

100% what it did in its original Philips player, no more no less, carbon copy !

I.e. :

1) Needs 98/99% trim to work.

2) If you just breath on the trimmer to rewind it half a bees dick, it will give you an aurora borealis and cut out/stop the disc immediately, so you don't get to see what the eye pattern would do for lower trimmer settings. Amplitude when working, again 100% the same, 2Vpp, just like the original Toshiba CDM.


SO !

Looks like the white CDM is not all that bad after all, and that the extreme laser trimmer setting is somehow normal for these players when they got switched to CDM4 in mid air ?

What do you think, shall we leave it at that and just take it as a learning experience for the next CDM4 enabled CD371 that we come across ?!  ;D
Shall we move on to the display problem now, or not ?
« Last Edit: April 19, 2021, 07:09:45 pm by Vince »
 

Offline Gyro

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #51 on: April 19, 2021, 08:02:37 pm »
Due to a rebellion among my Patreon supporters, I decided to unveil the next episode much earlier than I originally meant to.  ;D

That's Patreon supporters for you!  ;D

Well that was quite a stream of posts, lots to digest. your last post  seems to sum up the situation well though - the white CDM with / without the CDM4/19 replacement arm behaves the same on the Toshiba and the CD371. That's what we wanted to know, and rules out a lot of potential failure points / differences between the two players.

I haven't checked the laser pot position on my CD472 - frankly I'm a bit scared of doing so as the wiper has been in the same position for all of its long life, but I will look tomorrow.

I'm wondering if there were some later changes introduced later on in the era of mass market CDM4/19 players to give a more centred pot position, I'll go through my library of SMs.  It seems very risky for volume production that there would be so little adjustment range.

I think the focus offset adjustment is far less critical, and is aimed mainly at getting initial focus, rather than focus tracking. I have only played with that pot once before, on a Rotel player with definitely dying laser, it had some effect there, but minimal.

Your arm replacement procedure, even if humble, seems to have been fine. Theoretically you should go through the whole transparent disc, 'florescent light' procedure, but as long as the spring went back in the same position, I don't think it's that critical - as long as the arm is swinging visibly level, it should remain well within the focus range.

I think you have established that the Toshiba and CD371 PCBs are close enough that it rules out any gross fault on the CD371. Of course it may be that neither of them is working optimally and could do with some electrolytic PSU capacitor replacements, but good enough for now I think.

BTW, as well as looking at the eye pattern, the other useful indicator is to monitor the EFAB signal from the SAA7210 to the SAA7220 (SAA7210 pin 36 / SAA7220 pin 4). This is the indication of a raw uncorrected error which causes the SAA7220 to go into error concealment (interpolation) mode. You would expect a few pulses on any good CD, but it is a much more sensitive (earlier) indication of things getting into trouble than audible distortion.

In short, for now I would agree on 'good enough' and proceed with the display mod.


P.S. Well done on finally acquiring the paper clips (yours must be the only home in Europe that doesn't have one hidden down the back of the sofa or a desk drawer!), I hope you have now applied them to all arms not in captivity!  :-+
« Last Edit: April 19, 2021, 08:05:10 pm by Gyro »
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Offline shakalnokturn

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #52 on: April 19, 2021, 11:10:54 pm »
On the swing arms swapping:
I've done it before too on CDM2's / CDM4's it is easy and there really isn't room for adjustment.
If you do the same on a CDM0 or CDM1 you're in for some fun though...
 

Offline Gyro

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #53 on: April 20, 2021, 09:15:21 am »
Yes, they had optimised much better for mass production by that stage. As long as you don't snap the two little plastic locating pegs when you remove the spring plate it's fine (otherwise it gets like the earlier ones!). Gently lifting up the two little metal spring tabs helps you remove it without struggling and gently bending them back down allows them to line up spring against the pegs again.
Chris

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Offline Vince

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #54 on: April 20, 2021, 06:25:15 pm »
OK, so let's move on to the display problem now. Wil order the DIP version of the chip, some decent prototyping board, and do a quick and dirty proof of concept, before spending more money and time for a polished final product. While I am waiting a month or two for that stuff to arrive from china, let's look at the stuff that  my new grand pa electronic friend brought to me last saturday, as he promised he would.

Well I alraedy told you what he would bring, but now we can have a closer look. Shakal was curious about the monitor, and I want to hear your opinion if any, on the speakers he gave me.  Wrote down the info I could find tagged on them.

First we have some junk, which I have already taken apart and dumped the cabinets. A huge 5x100W 5.1 amp made by Hyundai, which apparently don't make just cars.  Their amp is made as cheaply as their cars, as ugly as well, so I had absolutely no remorse whatsoever taking it apart even though gran pa told me it works. I did not even bother turning it on as I have no use for a 5.1 home cinema amp, and even if I did, I would get something decent... Luckily, despite the ultra cheap design (almost shocking really, was surprised it could be THAT crap, really), it was full of cool things to salvage, not least was a huge toroïdal transformer, a million and half tactile switches for the front panel, some big ceramic packed resistors, a pair of big Nichicon caps, relays... this thins is tremendously more valuable and interesting for its parts than it is as a complete product !  :-DD

Then a couple DVD players. A Samsung and a Hitachi. Actually inside it was not that crap at all, you had your money's worth.  The pickup had a cool die cast metal body.  I did try both of them quickly, with an audio CD. Perforamance was terrible.
Turned out once I was inside, that they used the exact same chassis. So I have two of every board !

That's for the junk.

Now for the speakers. He gave me 4 of them. Wrote all the details and took pictures. I don't doubt that any of them would be 10 tiems better than my crappy small Toshiba speakers that came with a super low end stereo system.

Yesterday after work, paid a visit to the local electronics shop down town, as I am fortunate to have one. I guess one of 5 remaining in France...    :-\

Bought 5meters of audio cable so I can hook these speakers to my amp. The Toshiba speakers didn't need cables as they came with thier own cable hardwired, coming out of the cabinet.
Section-wise, talked a bit with the guy. We settled on a cable section of 0.75mm2.  Should be plenty enough for the mere 20% volume setting I am using on the amp.
Also bought a 2.5m long RCA to RCA male cable, so I can at last plug a CD player (or anything) under test on the bench, to my amp on the shelves. This way I can have the cable readily accessible on the bench when I need it, and I can just select the TAPE input on my amp to switch to the device under test. Quite convenient, like it.

So here is for the speakers.

1) A pair of large ones. MAde by " Boston Acoustic", made in USA, model HD9. Guy tried to educate ignorant me quickly. Said it was a 2 way system even though it looks like a 3 way one. The biggest "speaker" at the bottom (missing on one, and broken on the other...), is actually not connected to the sound source, no electrical connection. Said it was called a "passive" speaker. If I understood him well, the ideai is to reuse some of the internal acoustic pressure inside the cabinet, to the front/outside. This was you get a little bit more acoustic pressure outside, so a better efficiency for a given input power. Something like that ?!
They are broken and are crap anyway he said, so will salvage what can be, the filter(s), and dump the rest. Might keep the individual speakers though, as they are bound to sound much better than the myriad of crappy small speakers I salvaged from old TV sets and such...

2) A single speaker/baffle. Said it's not meant to be used as pair. There is still the sticker from the thrift shop he got it from, which says it's a "central" speaker.  Also, the orientation of the logo at the front, and of the sticker at the back, suggest that it's meant to sit flat, horizontally, not vertically like your usual pair of speakers. So I guess it's meant to be used in a 5.1 system ? Not sure what I can do as a lone speaker ? Still have full bandwidth ? It has a Tweeter along with too medium sized speakers, so might do it.  Has a port at the back too, as can been seeon on the pictures. Could use it as test speaker for example ? It's decent looking, decent build quality and compact, so easy to store and put on the bench if I wanted to connect it to some piece of gear quick and dirty ? I don't know... kinda cute so trying to find a use for it, a justification for keeping it...

Anyway, here is the info : Made by  "Studo Lab" 6 ohms not 8, model " Cine 02.2 Cent " . Its name kinda suggest it's indeed for a cinema amp, and does it also implies it's worth only 2 cents ?!  :-//    Power rating : 150W , yeah right..... Chinese Watts I guess...

3) A pair of Marantz speakers : Model HD 493. 70Watts.    Designed and Manufactured in the UK, it says. They are very compact.  Two way system with a port at the front. Guy said it was called a " Reflex "design ? Said it was meant to tune a resonance at some frequency, so that you would get more bangs for your buck,  better efficiency. Same  goal as the passive speaker then, but different technique ?
Sadly one of the speakers is missing the piece of cloth/ fabric that covers the cabinet. However it still has the frame that snaps onto the cabinet, it's only the fabric itself that's missing. So I guess one can buy standard replacement fabric, and I could reline both speakers with new fabric ?

4) Last one. A pair of Technics, model SB-C7, rated at 80Watts. Made in Spain.  3 way system this time, and no passive speaker or reflex port. Just a plain simple 3 ways system.

So to sum it up, the sound lad is not suitable as it's central / lone speaker. Boston ones are crap and broken anyway, and too large for my bench anyway. And I don't need big power.  So I am left with either the 3 way Technics or the 2 ways reflex Marantz. Any preference ? Will try both.  The Marantz is quite more compact than the Technics, so it's got that going for it, as I bench space is at a premium. And it's designed and made in England. Technics are made in Spain ! :-//

Will try both of them of course, to see, uh, hear them and decide which one I prefer. Maybe one of the is damaged / degraded after years of sitting in his shed, so I won't even have a choice....


Now let's end with the monitor, Shakal was curious...  turned out to be a good surprise. It's not as crap as I thought it was, from the crappy picture he showed to me on his smartphone the other day. It's indeed a Sony, and indeed a monitor, not a TV. No connection at the back for an antenna, no built-in antenna... just a monitor.

Among the stuff he gave me, there is a video camera, looks like a security camera ? Camera is a Bosch model LTC 0455/11 with an LTC 3364/60 lens mounted on it.

Monitor is model PVM-9000ME, colour, and with a cool Trinitron tube!!!  :D  It's small enough to be portable (has a beefy non fold-able/removable carry handle on top of it), yet large enough to be comfortable, you don't need a microscope to look at it, nor do you need to stick your nose to the CRT.

So looks like this monitor is designed to display CCTV camera images ???
Monitor has all sorts of weird proprietary connectors at the back, be it for the mains power plug that's non standard, or the plug for the battery pack. Has a DC barrel jack for an external power adapter as well.  Input is BNC only, with a switchable 75ohms impedance. Guess that means it can be used as a high-impedance input too ? Anyway, Video stuff uses 75ohms not 50, I know at least this much  :-[

It's so tempting to do a quick test, and power the monitor and hook it to the camera !!!  :D

I do have a 75ohm BNC cable, because when I asked my local shop for a coax cable to work on a frequency counter I was repairing, he gave me that cable... once back home I eventually realized it was 75ohms video cable, not 50ohms !!!!  :palm:

The camera has quick connect power terminal : just shove a bare wire in it, press a tab, and it locks the wire into place, convenient. Needs 24V AC or 12V DC. Could easily power it with my lab power supply, then.

As for the monitor, easiest I think is to power it with mains voltage, with a couple crocodile clips in the power socket... I like to live dangerously.

Will try to do that this evening, stay tuned !   :-BROKE


 

Offline Vince

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #55 on: April 20, 2021, 06:27:34 pm »
Sony Monitor and Bosh Camera.

 
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Offline Vince

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #56 on: April 20, 2021, 07:02:54 pm »

YEAH, RESULT !!!   :D

Shoved two wires at the back of the camera, connected to my lab power supply, 12V DC, draws 250mA or so. Thought hell, I can check the camera by itself, no need for a monitor just yet... I can just hook the camera straight to the scope and see what I get !

I get a nice composite signal, appears to work, it's alive !!! 

Scope is looking at itself albeit its composite self  !  :-DD

I like the composite video signal, sexy waveform, and looks so cool on an analog scope, could look at it all day !  ;D


 :D :D :D :D

 

Offline Gyro

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #57 on: April 20, 2021, 07:04:48 pm »
OK, so let's move on to the display problem now. Wil order the DIP version of the chip, some decent prototyping board, and do a quick and dirty proof of concept, before spending more money and time for a polished final product. While I am waiting a month or two for that stuff to arrive from china,....

You're ordering a salvaged e-waste MM5450 from China?  :o
Chris

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Offline Vince

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #58 on: April 20, 2021, 07:07:27 pm »
You're ordering a salvaged e-waste MM5450 from China?  :o

Googled the chip and only results were from shady Ebay and Amazon etc, none of the major retailers like Farnel  etc...   do you mean you managed to find one from a trustable / reputable vendor ??
 

Offline Gyro

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #59 on: April 20, 2021, 07:13:46 pm »
Strange, they're available brand new from Farnell, RS etc. here...  https://uk.farnell.com/microchip/mm5450yn/ic-led-display-driver-5450-dip/dp/2510523?st=mm5450

Also a couple of ebay sellers here. Actually cheaper than Farnell / RS for a new ST M5450 (makes a change!).  https://www.ebay.co.uk/itm/1-M5450-34-segment-LED-driver-IC-MM5450-M5450B7-MM5450N-5450-40-dip/280329718174  I don't know if they ship to France.
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Offline Vince

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #60 on: April 20, 2021, 07:43:00 pm »
Oh yeah you are right, looks like Google is being paid by Ebay and Amazon for returning only their results and ignoring the main vendors !
Just checked Farnell and TME, they both have it, in stock, and both the DIP and PLCC versions !

Thanks for waking me up, never trust Google, check by yourself !  |O

Farnell is abusing, selling the DIP version at 6,17 Euros before tax, so way more expensive than Ebay. But still affordable of course. They carry 3200 DIP packages in stock !  :o and only 500 of the PLCC one. Clearly someone at Farnell is thinking... they must check Ebay to see what niche market there is for such or such chip, among the DIY electronic people, and they decided to sell that chip ! No small business I guess.

Somehow, TME which is much smaller than Farnell, sell this chip for way less than Farnell !

Only 4,30 Euros (before Tax again), for the DIP package and only 3,14 Euros for PLCC !  :D

Hmmm... TME here I come ! Need to order some bits and bobs as well for another project, and also I broke my Weller soldering tip, need a new one.  Just need a pack of cheap but decent FR4 prototyping  boards, but this kind of stuff usually is prohibitively priced unless you go to Ebay and co. So these may take more time to come. Will try to find some from a local / European vendor so I can get them fast.


« Last Edit: April 20, 2021, 07:50:10 pm by Vince »
 

Offline Gyro

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #61 on: April 20, 2021, 07:48:04 pm »
 :-+
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Offline Vince

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #62 on: April 20, 2021, 08:15:55 pm »
Cool for the chip, looks like there will be some action much sooner than expected in the display department then !!!  :D

Plugged the camera to the monitor... was easier than expected, because turns out the weird mains socket is not proprietary after all ! 
It's strange one that I now recall seeing, once... just once before.  It's a 3 wire version of the slim 2 / flat 2 wire standard plug you get on any domestic appliance... like the CD players fdor example ! So grabbed a power cord from a CD player on the bench, plugs right in ! The earth pin is just not connected of course, but the power cord plugs in that socket perfectly !

So that was cool.

Excellent surprise, monitor works just fine, and picture quality of the combo camera + monitor is excellent ! Does not show on mly pictures of course, since my camera does not play well with CRT  of course, but you will have to take my word for it. In the second picture I take a close up shot of the power supply feeding the camera, and the picture on the screen is as sharp and real looking as I can see it with my own set of eyes ! Looks superb.  Actually picture looks truly exceptional for macro shots like this, but looks crappy / bluury from a distance. Maybe I could help it with the two controls available on the lens, but sadly one of them is broken. The screw snapped when I tried to un do it. So there must be a couple threads stuck inside, that keep the control from moving  >:( 

The " W -- T " control works. IT's the other one marked " N --- [infinite symbol]  " that's stuck to the " N " end of the adjustment range.

The macro performance is so good that the camera can focus with perfection onto the imperfection embedded on the objective lens itself !!!  :o

Monitor has PAL / SECAM setting, so I guess the camera must use one of these protocols...
Not versed into video stuff as you have gathered, but I get a picture regardless of the setting !  The only difference I can see is that when setting the monitor to PAL, I get a colour picture, and when I set it to SECAM, it is forced to black and white. Other than that...

The monitor of course is not brand new, so every now and then it goes haywire and I lose the picture. I guess some caps need changing in there, and some solder joints looked at ?!.....

But basically it works, camera has fantastic macro capabilities and that Trinitron tube is s sharp, a joy to look at.

I am definitely keeping these two !  :D

I already have a use for it !  I was given for free an oold portable HP serial protocol analyzer (HP 4951C), with a built in keyboard, floppy disk and a tiny green CRT.. that's completely burnt out !  :-\     But... the unit has a BNC output at the back for an external monitor ! From memory it uses some weird protocol but after some research, it's pretty much compatible with the american NTSC standard. Voltage levels may differ that's about it. If I can find an NTSC to PAL / SECAM adapter for chip on evil bay, I could maybe get it to display on that cool Trinitron monitor and the picture would be so much better and so much larger.

 

Offline tautech

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #63 on: April 20, 2021, 10:16:49 pm »
Nice scores Vince.  :)
Certainly the Marantz vented (reflex) speakers will be the ones to keep but the Technic's should be OK too providing none of their bass speakers haven't been damaged from too much power.

The Sound Lab unit is certainty a center front speaker for use in a surround sound setup.
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Offline shakalnokturn

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #64 on: April 21, 2021, 12:59:07 am »
Cute monitor looks early 80's, see now you've turned it on you've softened, should have taken it apart first!

I'm curious on your conclusions listening to the speakers, place them with tweeters about head level and not right against a wall (placement can make a whole difference in sound) make sure you get the polarity (phase) same on left and right sides.
I've heard some very good 2 way speakers but usually prefer 3 way, the improvement is usually obvious when listening to brass instruments.
A pity for the Boston's they looked decent too... The rest is awful but could still have it's sacrificial use for crash-testing amplifiers.
 

Offline Gyro

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #65 on: April 21, 2021, 11:01:12 am »
Yes, some reasonable speaker finds. I don't know anything about the Technics. The Marantz ones probably sound warm and laid back. Boston Acoustics were (are) a name. The probably have decent tweeters and midrange drivers. You might try looking for a pair of low cost woofers - the remaining one should give you the impedance. Having a midrange driver should ease the quality requirements on the woofers.

Edit: Sorry, I didn't read your post properly, I didn't realize that the Boston ones had passive radiators - also known as Auxiliary Bass Radiators (ABR). They take the place of a reflex port, with controlled mass and resonance. You could try blanking the holes and experimenting with different lengths of plastic pipe as a substitute (or stuff the holes with a sheet of high density foam).
« Last Edit: April 21, 2021, 11:51:54 am by Gyro »
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Offline Vince

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #66 on: April 21, 2021, 10:06:50 pm »
Cute monitor looks early 80's, see now you've turned it on you've softened, should have taken it apart first!

Yes, you are 100% right. I have softened. I am not proud of that. I must work on that, so that it never happens again. Take apart I must.


Quote
I'm curious on your conclusions listening to the speakers,


Asking me to comment on audio stuff is like asking my mum what she thinks of Shannon's theorem. It's not really relevant...
I know squat about audio and don't even possess the vocabulary to describe how I feel about this or that aspect of the sound. I am both utterly incompetent, as well as being unable to convey my thoughts so....

But well, somehow I do have some feelings so I will try to explain them. Feelings, not scientific facts...

First, I took apart the broken Boston. Broken and too big. I have run out of space in the house, and am not looking for a speaker "project"....  :-//  I accompanied them to their last house, the dump yard.  Of course I salvaged everything that could be,  ie the speakers, connector at the back, and the filter inside.

Quote
place them with tweeters about head level

That's exactly how it turned out to be, by sheer luck. Put the speakers on the bench, and I when I sit on the chair, my ears are just level with the tweeters. How lucky eh ?!

Quote
and not right against a wall (placement can make a whole difference in sound)


Yep. Put them at least 20cm away from the wall.

Quote
make sure you get the polarity (phase) same on left and right sides.

Yep thought of that. A bit of a pain since the cable is all black ! No red stripe anywhere. One of the wires has the insulator squeezed, it's been flattened a bit, if that makes sense. So if you look closely you can see it. Or you can feel it as well.


Then I installed my new 2.5m audio cable to connect the CD371 on the bench, to the amp. Then flipped a coin to decide which of the Marantz or the Technics I would try first. The Technics won. They sounded like shit, I mean like there is something seriously wrong with them, broken or something. Sounded like the mid-range speaker was gone. Put my finger on it and indeed it seems dead. The bass and tweeter, I could feel they were vibrating. Had to pump up the volume a lot to get a decent output. Singer voice sounded super weird and faint, like he was speaking from a mile away. Super weird sound. Checked the speaker on the other side of the bench... same problem. Suspicious.
Then Tried the Marantz to compare, same problem. Hmmm...
Tried using my "regular" CD player, the CDC 486.. and oh miracle, sounds fine now. So there is a problem with the CD371 on the bench, which I would investigate later.

So I did my testing with the CDC 486 (TDA 1543) since it was working.
The first thing I noticed with the Marantz was that I felt it had too much bass, so shaved it a little using the tone control on the amp.
Then at one point I heard the tweeter misbehave for a split second, was having trouble reproducing something. Occurred only once though...was specific to that particular moment of that particular song....
Not into classical music so not much into brass instruments. Prefer 70's/'80's pop/rock. Listened to my favorite singers, Daniel Balavoine and Queen, for an hour. Then same songs using the Technics. First thing that striked me with the Technics, in the first seconds, was the lack of "excess" bass the Marantz had, and also felt more comfortable / at ease with the high pitch stuff but.... but.... what annoyed me is that it sounds... "flat". Sorry, I told you I don't possess the terminology !  :-// 
I mean, it sounds technically better, bass and treble, but it sounds... flat. Dull. It's like looking at a picture printed on paper. It represents a nice landscape, but you can't be fooled : you know it's not the real deal, it's nothing compared to being there for real and experiencing it with all your sense and in 3D. Same here. It's like all the bits and pieces that constitute the voice of the singer and the music... are all equal, not one standing out. Like there is no depth to the picture, like an army of soldiers all lined up walking in unison. It's all well organized and pretty, but... it's not "moving", it's boring... no emotions.

But then after a while listening to these speakers I convinced myself it was better this way....

But it's impossible to compare without the possibility to instantly switch back and forth from one set of speakers to the other, in an eye blink... because honestly after listening to one hour of the Marantz, then an hour later listening to the same songs with the Technics.. brain has  long forgotten how it sounded with the Marantz. So, short of having a magical switch to do instant side by side comparison, I did the next best thing : after I had spent an hour listening to the Technics, I ended the show with a song I like particularly and where every improvement in sound reproduction is beneficial and brings more emotion to my brain cells. It makes it easier to spot the good and bad of the two speakers. Once I had played that song on the Technics, I rushed to rewire the Marantz and rushed to the CD player to play again the same song. This way my brain still had some recollection of how it felt to listen to that song on the Technics. Pressed PLAY again.... and wow, yes, my first impression was right. Marantz has its shortcomings explained above, but it also instantly made the voice sound much better to me. Not flat anymore. Felt clearer, sharper, like looking at that landscape in 3D not 2D. All the little elements that constitute the voice and music, seemed like individual characters that lived their own life, the little soldiers were suddenly freed. The voice sounded more "real", like the singer was there in my living room talking to me.

So I opted for the Marantz because of that. They are technically not perfect but I don't care about technical perfection, music is about feelings, emotions, and the Marantz extract notably more emotions and thrill out of Daniel and Queen, than the Technics. So... Marantz it will be on the bench.  Plus, they are a fair bit smaller than the Technics, which is a plus since bench space is at a premium...

Then I wanted to try the CD371 to see if its TDA1541 would make an audible difference. It clearly did (placebo effect ?!...). Had the same effect to me that I felt when going from the Technics to the Marantz. Felt yet again a bit more "real", more "alive".

That means I found the problem with the CD 371 crap sound.... turned out not to be the CD player. I eventually realized that this strange weird sound... I had already heard it before somewhere !!!  Yes, I had exactly, 100% the same sound pattern when I was fixing my Sony amp headphone jack, if you remember !  Back then Gyro found the problem : bad/missing ground for the return path of the head phone. So, I checked my brand new RCA cable, grabbed my DMM and checked the cable. Did not take long to confirm my suspicion ! Ground problem indeed ! I get 2 ohms resistance between both ends of the inner conductors / center pins of the RCA plugs. On both channels.
However when I tested ground, the outer ring/shell.... on the white connectors, a solid open-circuit, and on the red channel, a bit random, either open circuit, or one or two Mohms...
So I grabbed my old (much shorter....) cable, and hey presto, problem fixed. So I could try the CD371 now, and found it an improvement over the TDA1543 of my CDC 486.

I guess now, the next step is to get a decent amp. My Sony is really a bottom of the barrel piece of crap. I am curious to see if I notice a difference with a decent amp.

Midnight here, time to be to bed. Shakal however, being 120° out of phase, is only just about to wake up, he might soon be reading this I think....

Anyway, time to fix this display problem on the CD371 so I can button it up and use it as a regular player, for single disc stuff at least. Still enjoy my 6 disc changer when working on the house or on the bench where I don't fancy stopping my work every 45 to 60 minutes to replace a CD.

Anyway, quite happy to have a half decent installation. Nice to listen to all my old CD's with decent sound. Just closing my eyes and enjoying the songs a bit loud without distortion. Thrilling....

Can't wait to have decent amp, preferably broken and super cheap, of course!  ;D

Now need to go back to the electronic shop down town, armed with DMM, and ask for a replacement cable... hopefully that will work this time...
« Last Edit: April 21, 2021, 10:18:27 pm by Vince »
 

Offline tautech

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #67 on: April 21, 2021, 10:42:55 pm »
The Technics crossover caps are probably sick.
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Offline Vince

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #68 on: April 22, 2021, 06:25:41 pm »
"Cross over" caps ?! Lemme Google that... oh, fancy name for the filter board ?! :-[

Google served me this page :

Quote
https://www.electrocube.com/pages/capacitors-in-audio-crossover-networks-data-sheet

A company that specs /designs and make (get made I guess...) their own audio caps.

They say that film cpas are best, and that aluminium electrolytics are the worst, and that bipolar electrolytics are even much worse than regular polarized ones. Guess what I have in the Technics ? 100% bipolar electrolytics, mouarf..... it's not just made in spain then.. .it's also designed on the super cheap as well ?! Crap....  :-//

See pics. 3 caps on the board, all bipolar electrolytics.

Brand : " ROE " or " RDE ", not sure how to read their logo...

Series : " EKT "

Temperature range : 105°C

Voltage rating : 63V for all three.

Capacitance values : 1,8uF 2,2uF and 10uF

Measured them, they all read spot on. Can't see any bulging a the top. No sign of leakage on the board either, though could be hidden underneath the caps since they are sitting really flush with the board, so would need to desolder them to be sure. However typically if they are dried out, capacitance value goes up, I find...

Went back to the electronics ship in town. Guy replaced the faulty audio cable no worries. We tested all 4 wires for continuity before I left, to keep me from having to come back again...
Just fitted to it to the lab, works fine, great. I am now much more comfortable to test audio gear, cool....

« Last Edit: April 22, 2021, 06:29:07 pm by Vince »
 

Offline Gyro

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #69 on: April 22, 2021, 06:58:43 pm »
Aged electrolytic crossover capacitors tend to make speakers sound dull rather than bright (note that all capacitors in crossovers are bipolar types, you can't substitute polarised ones). 3-way speakers can have issues with phase and matching in the transitions between drivers in the vocal mid-range range depending on the quality and complexity of their crossovers and crossover frequencies. With small speakers it is often easier to manage the single crossover point and integration of two drivers than three.

I suspect that the Technics speakers are more technically 'accurate' and may reveal more about other parts of the chain (the Amp for instance), the drivers may also integrate better at greater listening distance than close up.

As I mentioned, I remember Marantz speakers as being warm and inoffensive - not necessarily accurate, just nice to listen to. Regarding the excessive bass output, that may be down to placing them too close to the wall. One very quick and simple experiment that you can carry out is to take your socks off (or even use clean ones!) and stuff one into each of the reflex ports, turning them into resistive ports. That should lower the bass output and extension.

It's a shame about the Boston Acoustics ones - I actually saw some pretty positive user comments about them on the web. Maybe you could mount the salvaged drivers in some smaller basic MDF cabinets.
Chris

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Offline tautech

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #70 on: April 22, 2021, 08:21:01 pm »
What Gyro said ^.
Bipolar electrolytics have been used in crossovers forever however like any electrolytic they do degrade but as yours tested OK for value they might also need their ESR checked against new ones. Not been down that rabbit hole.....  :scared:
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Offline Vince

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #71 on: April 22, 2021, 10:44:07 pm »
Thanks for all the info gentlemen, you never fail to deliver ! :-+

Planning on getting an ESR tester pretty soon, so when I do I will be able to check those caps. If bad I will see how much it would cost to replace them with quality audio graded caps but I fear they would only be available from some audiophool website that ells them at 10 Euros a piece, so that would be a no-no. I am not a milk cow...

Plenty of clean socks I don't use over here, don't know what to do with them, now I know !  :-DD

WIll keep all the Boston parts in one place and label them so I don't forget what they are in the future, when I will stumble pin them...
However designing a new cabinet to go with these parts, is an art and science in itself which I obviously don't possess. Today at the electronics shop, while waiting for over an hour, I noticed an old, thick book solely dedicated to cabinet/speaker design... just skimmed the surface and it made my head hurt...

Would still potentially like to build my own cabinet / speakers one day, as I like fine wood working, another hobby of mine, and have any kind of particle board in disgust. So would like a cabinet in plain wood using a species that I like the color and look/pattern of. Unfortunately, from old memory, I seem to remember reading that particle board, though disgusting and cheap/crap for the wood enthusiast like me... is actually much better for cabinet design than plain wood, to its better mechanical characteristics. An perfectly even material, with known specs, that's perfectly even/homogeneous material, etc etc... I can understand that, but it sucks   :(  Covering it with a fake plastic film imitating the look of wood is just adding insult to injury !  :--

So I don't know....

One thing is for sure and you seem to agree with it... is that I need to get a better / decent amp !  Again I guess it's gonna have to be (?) something from the late '80s early '90's ?  Open to suggestions...
Woud like something with lots of stuff in it. A big toroïdal transformer because I love looking at them, and lots of discrete power transistors   ;D Want a quality front panel too. MY Sony amp has really crap looking/feeling plastics, horrible. Ideally would want a machine black painted or anodized thick aluminium sheet as the front panel, and aluminium knobs to suit. It's the complaint I have with the old CD players... nice electronics but crappy bottom of the barrel plastic front panel. It's not impossible to make plastic front panel look with a decent quality factor, look and feel... but it's more effort and money and I guess CD players were not sold for enough money to make such an effort a viable option... I guess they though nobody would want to pay more for a better quality front panel...


See you later....  :=\

 


Offline Gyro

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #73 on: April 23, 2021, 11:39:06 am »
WIll keep all the Boston parts in one place and label them so I don't forget what they are in the future, when I will stumble pin them...
However designing a new cabinet to go with these parts, is an art and science in itself which I obviously don't possess. Today at the electronics shop, while waiting for over an hour, I noticed an old, thick book solely dedicated to cabinet/speaker design... just skimmed the surface and it made my head hurt...

Would still potentially like to build my own cabinet / speakers one day, as I like fine wood working, another hobby of mine, and have any kind of particle board in disgust. So would like a cabinet in plain wood using a species that I like the color and look/pattern of. Unfortunately, from old memory, I seem to remember reading that particle board, though disgusting and cheap/crap for the wood enthusiast like me... is actually much better for cabinet design than plain wood, to its better mechanical characteristics. An perfectly even material, with known specs, that's perfectly even/homogeneous material, etc etc... I can understand that, but it sucks   :(  Covering it with a fake plastic film imitating the look of wood is just adding insult to injury !  :--

You might look at the details of some of the smaller speakers in the same range - eg.the HD7 (I didn't look extensively) to see if they use the same drivers - only the bass driver is relevant when it comes to the cabinet details. The smaller ones all seem to be sealed enclosure rather than reflex (or ABR), so you wouldn't need to worry about port tuning, just the overall volume and add some fibre filling. 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.

Then you can try designing and building some serious speakers...  :D


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. You could always make 'composite' cabinets with MDF lining and real wood exterior though. The best of both worlds.
« Last Edit: April 23, 2021, 11:45:41 am by Gyro »
Chris

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Offline Vince

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #74 on: April 23, 2021, 02:12:43 pm »
https://uk.farnell.com/webapp/wcs/stores/servlet/Search?catalogId=15001&storeId=10151&langId=44&categoryId=700000100508&st=non%20polarized%20electrolytic&beginIndex=3&showResults=true

Yep but these are generic ones. All the audio boy keeps yelling that the wrong choice of cap makes of breas and amp or speaker, that's why they use fancy expensive "audio grade" caps, some brands specialize i audio caps and make nothing but that...
Not knowing where the facts end, and where audiphoolery begins... it's hard to say, being clueless.

At the very least, to be safe, I would need to find the exact same brand and model/series of cap. Or at least find the datasheet for them and try to find a suitable replacement.

 


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