Author Topic: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371  (Read 6955 times)

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Offline Vince

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #100 on: May 05, 2021, 05:44:28 pm »
Hmmmm... I don't even want to check prices for these things, I have no intention to spend money I don't even have, for a nice cabinet, I am happy neough with my plasticky Radiola and Toshiba....

OK, trying to order from Farnell.... looks like the bastards have changed their policy ! No free shipping anymore above 15 Euros... there is now no minimum order, but a fixed 10,68 Euros "fee" that applies no matter what.

TME has no fee but a fla shipping charge of 9,48 Euros...


So, all in all... TME and Farnell now have similar policies, and I will be lose 10 Euros no matter where I order from and no matter how large the order is. Sucks !

So I checked, just for fun, a local / small electronics shop, in the next big town 40 miles away. They have a website I order there from time to time. I am stunned : they DO carry this bloody MM5450 shift register !!!

http://www.e44.com/composants/composants-actifs/circuits-integres/circuits-analogiques-mixtes/drivers-led/nmos-ic-led-display-driver-dip40-MM5450N.html

Of course more expensive than Farnell, but not by all that much : 9,50 Euros vs 7,40 for Farnell. Shipping is only 3,50 Euros, not 10,68 !!!  And free pickup if you can get to their shop. It's 40 miles away does not make economical sense in my case.

So... fuck Farnell !!!!

Too bad for the Electrolube SPG, will have to  find some elsewhere, in smaller  and cheaper quantities...or another brand. Looks like Molykote makes some plastic grease too. Many flavours at that, hard to chose :

https://www.lubricantspecialty.com/categories/application/plastic-lubrication

 

Offline Gyro

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #101 on: May 05, 2021, 06:39:35 pm »
That's a shame, I think many of the suppliers are sneaking in delivery charge changes again. Gone are the days when RS used to have free delivery on all orders for instance.

I'm sure a Molykote plastic grease would be fine too, I think I've seen it specified for some linear pickup systems. The only real requirements are to stick well to slippery plastics, not migrate, and of course, not have chemicals that degrade sensitive plastics (that one can take about 20 years to find out!).
Chris

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Offline Vince

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #102 on: May 07, 2021, 07:30:43 pm »
OK I am losing it... when I read Farnell's terms and conditions, I understood you got the 10,68 Euros fee no matter what. Now, I put all the bits I wanted in the shopping cart just to see, and when it states clearly at the top of the shopping cart that the 10,68 Euros fee goes away for orders above 30 Euros (before tax, so 36 Euros or so incl VAT). Indeed, tehy did not charge me anything..... so I ended up ordering from them in the end, so the Electrolube SPG plastic grease will be here soon, yeah... can't wait to taste the stuff ! Given how expensive it is, it HAS to taste delicious, HAS TO !  :P

I am now officially 54,14 Euros poorer. 40% of that just for the grease, ahem....
Well at least I have a life long supply of the stuff, handy, and a large 100x160 proto board that can alwyas be reused for lots of things, and of course I bought all the bits I needed for the little design project I am doing for a friend.  So not so bad in the end...

Wanted to buy some 63/37 0.8mm solder, but looks like it's defunct. 60/40 rules the market. Even then, cost bloody 25 Euros for a small 100gram spool ! This has to be a joke... so did not buy any. Maybe COVID is an alround excuse across the vendors to doubles prices.... will wait for COVID to go away and the economy to recover, before checking prices again...

Can't wait to receive my order and to wire up that shift register see what I can come up with !  :box:

They did warn me that shipping times were affected by COVID, but I doubt it would delay my order by more than a couple days over normal. We shall see...

Anyway, stay tuned, some action soon !  8)

 

Offline Vince

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #103 on: May 09, 2021, 04:34:45 pm »
Hmmm... that's a weird one. Maybe you people can enlighten me...

I just managed to fix another player in the stack. Have a couple twin brothers : a Sony CDP-C335 and a C365. Both have a damaged plastic gear, but not the same one. So I can make one good player out of the two. Which one gets to live and which one gets to be the donor, was obvious : the 365 was damaged during transport, big crack in the bottom left corner of the front panel. Also, the Sony logo at the front is missing, somehow. Plus, it's lesser spec than the 335 : 335 has head phone jack at the front, with volume control. 365 has no jack.  So, I fixed the 335. Works like a charm, been playing music for a couple hours at least now, flawlessly. However of course I wanted to check the amplitude of the eye pattern to see where it's at.

My problem is that when I connect the scope to the RF output to check the eye... the player somehow all of a sudden fails to detect the discs ! If I disconnect the scope, start playing music, then while it's playing I connect the probe to the scope... a couple seconds later, the player can't read the disc anymore (time counter stops) and the player stops the disc !  :o

Oh dear...

I thought maybe a ground issue, but precisely to avoid that, I powered the CD player from my isolation transformer. Plus, I shouldn't even need to do that, since the player has no ground connection, and linear power supply so the transformer already isolates the player.

So I thought, maybe the RF signal is very weak, and the scope probe in x1 mode is too much of a load,  weakens the signal just enough to make the signal too small for the player to maintain operation.
Fair enough.. at a time base of 500ns I should not be using x1 anyway, I guess... so I switched to x10 to increase the impedance of the probe.... still no luck, no change.

The RF is checked directly at the output of the pickup, as per the manual, rather than at the output of the Rf amplifier.. probably because looking at the schematic, teh RF amplifier is not accessible, looks to be embedded inside the main decoder chip. Still, even then, the manual says that I should be getting a strong signal, 1,2V or something... so there is some kind of amplification going on in the pickup itself ?!...


Anyway, I don't understand what's going on... I fear I might have to sell this player without being able to know the amplitude of the eye, and that makes me feel uncomfortable.... don't want the player to "magically" stop working once the buyer gets it. Well, assuming someone wants to buy it of course !  :-DD

Any similar experience or ideas on the subject ?!....  :-//

« Last Edit: May 09, 2021, 04:47:47 pm by Vince »
 

Offline Gyro

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #104 on: May 09, 2021, 05:28:26 pm »
I certainly wouldn't expect it to work with the probe on X1, too much loading.

With X10 it really depends how much loading the signal will take - It could be that the 10M input resistance is upsetting the DC bias point of the signal for instance. It should work with the scope set as specified in the service manual though.

Sorry, Sonys aren't my area!  ;)
Chris

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Offline Vince

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #105 on: May 09, 2021, 05:51:10 pm »
Yeah my problem with teh loading hypothesis, is that well, the manual tells you to scope on that particular test point, so should not be any problem.
They don't even tell you to use x10. They even states to set the scope attenuator to 200mV/DIV, which implies the probe is set to x1 not x10...

I am not CD player racist  :-DD  If I were, I would never have bought a little Radiola and Toshiba, and would have missed on the best stuff !  :scared:

Maybe Shakal will have an idea...

 

Offline shakalnokturn

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #106 on: May 09, 2021, 07:34:23 pm »
I've run into the problem before not being able to scope the eye pattern at x1 and having to switch to x10 to not disturb the player.
Probe and scope input capacitances are worth considering as well as any close source of interference that may be injected by hooking the probe.

What amplitudes if any were you able to measure probing at x1 and x10?
What model is the pickup?
How picky is the player on dirty/scratched CD-R discs?
 

Offline Vince

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #107 on: May 09, 2021, 08:15:32 pm »
Probe and scope input capacitances are worth considering as well as any close source of interference that may be injected by hooking the probe.

Hmmm.... if it's that sensitive a thing, then I am thinking the problem might come from the fact that it's not possible to scope the RF directly (unless I put the scope vertically on its side.. doubt it would operate happily this way....  :-\ )  .. so I did what I always do : I solder two long wires to the test points (RF and ground), so that I can put the player in its normal position, and have the wire coming out on the sides.. then I can hook the probe to the end of these wires. Wires are quite long as a consequence... I don't know, 40 or 50cm maybe.
I could try using some coax cable instead of mod wires, or solder tiny wires on the board, only 3 or 5cm or so, just enough to be able to grab them with the scope probe.. but then the probe would be sitting under the player... so I would need to raise the player feet by a few centimeters so that the probe can lay underneath it without being squeezed or shorting anything on the PCB...   
Yeah, I will try that.... tomorrow. Too late and tired this evening.

Quote
What amplitudes if any were you able to measure probing at x1 and x10?

Could not measure anything, not enough time, the player fails way too quickly once I connect the probe to the scope....  >:(
Seems to fails equally fast whether I use x1 or x10 though.

Quote
What model is the pickup?

It's a common Sony KSS-140A.

Quote
How picky is the player on dirty/scratched CD-R discs?

Have not tried any CDR, would need to make one. Don't even know if I have blank CDRs left.... will search in my boxes of stuff see what I can find....

 

Offline shakalnokturn

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #108 on: May 09, 2021, 08:54:47 pm »
I'd definitely review the probing method, above 1MHz the loose wires are going to give you unpredictable results.
AFAIK the KSS-140A has no integrated amplification, only diodes.

As a side note and I think I mentioned it on one of your other topics: If the player uses a small double-sided PCB attached directly under the transport it is usually worth checking (in most cases replacing) the 3 SMD electrolytics on the hidden side. This involves desoldering the motor terminals. I'll usually make the most of it to clean the position switch contacts too.
« Last Edit: May 10, 2021, 08:46:09 am by shakalnokturn »
 

Online tautech

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #109 on: May 10, 2021, 02:29:19 pm »
It may be an idea to get a low input capacitance 100x probe as typically they're down ~6pF ....that's if you have sufficient scope input sensitivity for LV work.
The additional voltage rating may also be useful when you come to fix that stack of CRO's you have Vince.
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Offline Vince

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #110 on: May 10, 2021, 05:59:38 pm »
I'd definitely review the probing method, above 1MHz the loose wires are going to give you unpredictable results.

Yep that was it indeed, problem fixed !  8)
I measured my wires.. were 40cm long, so 80cm total to pick up noise and crap (and add parasitic capacitance).
I trimmed the ground wire (not really ground actually, if you look at the schematic) to the bare minimu, 4 or 5cm, just so I have enough to grab it with the alligator ground clip of the probe. Then the wire for the RF signal, I disposed of entirely, and probed the test point directly with the tip of the probe. Was kinda doable if I tilted the player 30°... at that angle apparently it can still play CD's just fine, and it gives me just about enough clearance to see what I am doing, and gently aim the probe where I want it to go.  You must no shake or all hells are loose.. but it's doable. Given that you fully know what to expect on the scope, it's already set as required to be able to se the waveform, so you don't need to fiddle with the controls. I just lift the player with noe hand and hold the probe underneath the player with the other hand, and look at the scope at the same time... no shaking allowed...

Doing that, it worked perfectly. I could see the eye pattern just fine, even in x1 not x10, and the player was playing perfectly fine, reliably.

So lesson learned... long wires to check the eye do (can, at least), matter to the point of sometimes keeping the player from reading the disc.

Oh yeah, forgot the most important... the amplitude of the eye is 1.0Volt, well withing spec (0,8V to 1,4V), so I won't be touching anything, works fine. I can button it up and put it up for sale....
Well OK, will try and burn a CDR to see what it does, if just out of curiosity, though one is not supposed to read a CDR on an old player so a potential customer can't possibly complain if CDRs don't work well, or even at all.



Quote
AFAIK the KSS-140A has no integrated amplification, only diodes.

Yeah I am a bit baffled that the pickup can output a strong signal, I must be misreading the schematic.... but it looks quite straightforward  :-\

[quote}As a side note and I think I mentioned it on one of your other topics: If the player uses a small double-sided PCB attached directly under the transport it is usually worth checking (in most cases replacing) the 3 SMD electrolytics on the hidden side. This involves desoldering the motor terminals.

I don't recall you mentioning that, but my memory is very lousy so...
I of course do remember though, you and Gyro mentioning the blue axial Philips on the laser drive. But that's about it.
Yep there is a board stuck under the mechanism. Sony always calls it the " BD " board, whatever they mean by that....
In this player I see if pretty much integrated the entire player .. servo/motor driver, decoder, and even the DAC, featuring built-in digital filtering/processing. So the transport actually outputs directly analog L/R audio signals ! Only thing that's left on the main board is a chip that amplifies both channels at the same time (no discrete / individual op-amps) and that's about it...
« Last Edit: May 10, 2021, 06:15:14 pm by Vince »
 

Offline Vince

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #111 on: May 10, 2021, 06:29:31 pm »
It may be an idea to get a low input capacitance 100x probe as typically they're down ~6pF ....that's if you have sufficient scope input sensitivity for LV work.

Yep, sensitivity is key. Most scopes are 5MV, some 2mV, but the noise floor is high so in practice it's hard to measure with decent accuracy, or get an exploitable / clean /stable enough waveform for signal below 10mVpp, I find.  Of course in storage mode I can apply some averaging to help, but the eye pattern looks crap, unusable in storage mode. Only analog mode can represent it properly. YMMV.. but my old Fluke/Philips combiscope just can't make a good job of it in storage mode.

Quote
The additional voltage rating may also be useful when you come to fix that stack of CRO's you have Vince.

Well regular probes are given for 600Vpp IIRC, so plenty good enough no ? Voltages in the old Tek scopes is about 500V max depending on model.
But that's DC, and for DC I have my 10kV HV probe that I can hook up to my DMM anyway, so that takes care of it. I bought it when I restored my first old Tek, the little type 317. It had CRT HV problem, HV was dying as it warmed up, so I bought the probe so I can take measurement to help with troubleshooting, and then let me calibrate the anode voltage properly.

But yeah, generally speaking I would love to have lots of special purpose probes for the scope.
A mini current clamp for my DMM, to check device consumption. AC current probe for the scope to check switching supplies, or check noise on power rails or what have you.
Then a HV diff probe like the one Dave sells, so I can probe on the primary side of an SMPS when I work on whatever device... or to check HV in my old Tek scope as you said, when not referenced to ground. Or just as precaution to avoid blowing my scope(s)....

But it all costs money. Other problem is that I heard of someone down under in New Zealand who buys ALL probes for sale worldwide, so the supply is running dry because of him !  Can't remember his name. I think he sells Siglent stuff over there, maybe you know him ?! :P

I think an HV Diff probe would be my next probe purchase, when money permits.
Then a current clamp, both for the DMM and the scope.

« Last Edit: May 10, 2021, 06:33:17 pm by Vince »
 

Offline Vince

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #112 on: May 10, 2021, 08:40:06 pm »
Found the few CDR discs I have left, burned one, filled it completely with a random selection of my favorite songs.

Improved my probing technique... now safer and hands free : raised the four corners of the polayers with boxes of screws. They are all the same size and are large enough for the player to be stable, but small enough to free enough space on the sides for the probe to stick out. Then sat the probe on a spool of solder to support its weight and bring level with the player.... then I could play all I wanted with the player while playing with the scope.

So, this 30 years old player reads CDR just fine thank you very much !!!! Who said they couldn't...
And my CDRs are 15 year old (if not more) and I bough the cheapest crap I could find that day at the supermarket, IIRC...
Yet, works just fine !  :-+

I burned the disc at the slowest speed the software would allow, which is x8. Still quite fast if you ask me. Seems like yesterday when a x4 CD player was a state of the art ultra fast piece of gear for your computer...

I noticed that the eye pattern as expected, decreased a bit in amplitude, at shy under 800mV, which is the minimum the service manual calls for (was 1.0 with anormal/pressed  disc). Also noticed somehow, and I don't have an explanation for that one, that the closer you get to the outer of the disc... the weaker the signal becomes. Not by much of course, but enough that it caught my eye. The inner / first track is almost 800mV as I just said, and the last track at the end of the disc, is more like 600mV.  So that is below spec. Still, even that last track plays just fine, never misses a beat, and fast forward/rewind work perfectly, fast and smooth.

So basically  even with a slightly weak signal, it can read a CDR perfectly reliably, still snappy, perfectly responsive.

So I can sell that one with total peace of mind... will even be able to advertise its CDR capabilities despite its old age.

 

Offline shakalnokturn

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #113 on: May 11, 2021, 06:27:28 am »
As a side note and I think I mentioned it on one of your other topics: If the player uses a small double-sided PCB attached directly under the transport it is usually worth checking (in most cases replacing) the 3 SMD electrolytics on the hidden side. This involves desoldering the motor terminals.

I don't recall you mentioning that, but my memory is very lousy so...
I of course do remember though, you and Gyro mentioning the blue axial Philips on the laser drive. But that's about it.
Yep there is a board stuck under the mechanism. Sony always calls it the " BD " board, whatever they mean by that....
In this player I see if pretty much integrated the entire player .. servo/motor driver, decoder, and even the DAC, featuring built-in digital filtering/processing. So the transport actually outputs directly analog L/R audio signals ! Only thing that's left on the main board is a chip that amplifies both channels at the same time (no discrete / individual op-amps) and that's about it...

Yes BD board it is, attached you a couple of stolen photos, see the less populated side having SMD Nichicons?

It was here, maybe not emphased enough though:
https://www.eevblog.com/forum/repair/vintage-cd-player-repair-sony-cdp-291-with-transport-issues/msg3531316/#msg3531316

 

Offline Vince

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #114 on: May 11, 2021, 06:32:48 pm »
Yes BD board it is, attached you a couple of stolen photos, see the less populated side having SMD Nichicons?

Ah yes, I seeeeee !  ;D

The dreaded SMD caps...

Just looked on my poayer, see below. None of these caps. Instead they used more modern Tantalum/polymer caps ? The small axial black packages...

Have 4 of them. 3 on the visible/accessible side of the PCB (6,8uF 10V), and one on the hidden side (4,7uF 10V).

According to the schematic, they all decouple the +5V rail for the digital stuff (DAC and decoder) only. Not meant for the servo/motor driver IC. That one uses only the +7FV rails and it does not feature any electrolytic.

Oh, about the pickup... I said it was a KSS-240A.. was a bit quick. Now that I took a close look while removing the BD board... turns out it uses a KSS-390A instead.  Schematic says that the player can be supplied with either pickup.



 

Online ebastler

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #115 on: May 11, 2021, 07:14:13 pm »
You should start looking for a Studer / Revox CD player.
You're not going to like the price though...

Studer/Revox made great tape recorders, for a hefty price.
But aren't their CD players just rebadged Philips players (for a hefty price)?
Philips CDM drives, same TDA1541s, same op-amps, ...?
 

Offline Vince

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #116 on: May 11, 2021, 08:12:41 pm »
Yep maybe, I don't know... the point of this old message you dug out was not about their technical merits (if they are old Philips inside then that's rather good ! ), but only about the overall build quality and quality feel of their cabinets/chassis/ front panels.

 

Offline Gyro

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #117 on: May 11, 2021, 08:30:53 pm »
Yes, their I/V and audio filter stages are stock Philips circuits. They are probably better in terms of PCB routing, grounding, supply rail noise etc. Pretty subtle stuff though.


Edit: Sticking my head above the parapet again now shakalnokturn has done a good job on the Sony.  :)
« Last Edit: May 11, 2021, 08:33:50 pm by Gyro »
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Online ebastler

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #118 on: May 11, 2021, 08:53:45 pm »
... the point of this old message you dug out ...

Hey! What's six days in the fast-paced world of vintage CD players?  ;)

I dunno... I feel that Revox realized that they had not much to add to this new game of digital audio (except for a loyal customer base willing to pay a premium price for well-designed mechanisms). It does not look like they actually tried to make their versions of the CD players perform better than the Philips originals. They could at least have given them different analog stages if they had wanted to.

When it comes to build quality of the chassis and front panel, nothing beats a Philips CD 100 in my view: Massive die-cast chassis, and a one-piece top and front panel which looks and feels like it is milled from a solid block of aluminium. (It probably isn't...) The Philips engineers probably wanted to play it safe in their first CD player, and they did a very nice job.
 

Offline Vince

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #119 on: May 12, 2021, 05:30:59 pm »
Excellent timing : just received my Farnell order.  Just before bank holiday Thursday, and the week-end (I work on Friday).

So I have both the bits, and some time... some action real soon  8)

Protoboard and shift register for the CD371, Electrolube SPG to pamper the CD824 before I put it up for sale, and other bits for my other little design project.

Life is good  :)

« Last Edit: May 12, 2021, 05:32:31 pm by Vince »
 

Offline Vince

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #120 on: May 13, 2021, 04:11:12 pm »
Can't beliece it, that CDP-C335 is ALREADY sold ?! I have not even had time to advertise it yet !  :-//

... Remember the CDP-C305 I sold a days back for 40 Euros, no questions asked ? Was a miracle in its own right... a new miracle happened. I forgot to remove the ad. Was long lost in the abyss of the search results of course, yet somehow last night someone left me a message asking when it would be possible to drop by to test AND buy the player ?!  I said sorry already sold, but have his big brother ready for sale if you like, CDP-C335.
Guy showed up an hour ago, and did buy it, again 40 Euros, not even trying it discuss the price !

Said his own CD player, also a Sony 5 disc changer, packed up just yesterday, his daughter was very sad about this, so daddy rushed online to see what he could find locally... was so happy to find a nearly identical player, tested and "warrantied"...

He even brought his old broken player for me to have a look at ! Guy stayed 20 minutes while I was having a look at the thing, in case it was something obvious. Couldn't fix it on the spot, so he said I can keep it !  :D

It's a Sony CDP-CE375.  Similar but 10 years newer than the CDP-C335 I just sold him.

So here I go, hoping to fix it for cheap and make a quick buck from it.

Symptoms : drawer does not open, and the player makes a continuous motor noise, never stops.

First checked the carousel motor. Its belt was very loose. Replace it with what I could find in my donor drives... a belt that's way too tight, but at least it "works".   Good enough for diagnostics purposes.

Drawer still would not open, and still that horrible motor noise... found it was the other motor, the one that drives the big "loading" gear as Sony calls it. Easy diagnosis : it's belt was so tired/loose that it flew off of the wheels ! Found the belt laying at the bottom of the chassis...
Replaced it with yet another belt from yet another donor drive... belt is much more "fresh", but sadly too long. Still kinda works : the drawer can now be opened and closed. So, Two belts that need replacing, but temporary replacements are good enough to carry on troubleshooting.... because, no, it STILL does not work... this puppy is sicker than your average drive, yet it's 10 years younger hmmmm.... :--

Remaining symptoms : the player just will not stop rotating the carousel ! Looking at what's going on on the VFD display while looking at what the carousel is doing... it looks like the player fails to detect the presence of discs : it just spins endlessly trying to reach, say, slot number #3 of the carousel, but it never can't find it !
I also notice that it does pause, very briefly, a split second, at each disc.. which is normal. What is not normal I find, is that whenever it pauses to try and (fail to) detect a disc, the carousel is NOT lined up with the CD transport ! Nope, it stops right in between two slots.

So that might be a clue ?! Maybe the carousel can't be placed in just any location ? Might need to "synchronized" to the tray, somehow ? I never had this typt of problem with previous carousel changer, so I am not sure this is it...
There is a infra-red detector inside the tray, so might want to look at that. Also a switch protruding from the mechanism, into the bottom side of the tray. Might be worth checking that one too.

Sorry Gyro, I know you don't love Sony's all that much, but this one is saleable I think so I will try to fix it.. will pay for the part to fix the CD371, see it that way, a necessary evil !   ;)

Will try and download the service manual, see how it works exactly.

At least there is something I recognized straight away : it sports the usual ' BD' board ! Looks like they used that one for 20 years !  :-DD

Any suggestion on where I might go to buy an assortment of rubber belts of various sizes ?!
 

Offline Gyro

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #121 on: May 13, 2021, 04:39:08 pm »
Sorry Gyro, I know you don't love Sony's all that much, but this one is saleable I think so I will try to fix it.. will pay for the part to fix the CD371, see it that way, a necessary evil !   ;)
...
Any suggestion on where I might go to buy an assortment of rubber belts of various sizes ?!

As long as you keep getting rid of them, I'm happy.  :)

No real suggestions on the belts. the local UK CPC arm of Farnell (a company acquisition) sells them but not as assortments and probably not useful for France... https://cpc.farnell.com/w/c/audio-visual/av-spares/prl/results?st=belt
Chris

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Offline Vince

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #122 on: May 13, 2021, 05:11:42 pm »
Thanks for the link, at least it shows what's available and at what kind of price.

Most of them are noted as "UNBRANDED", which mean that copany buys them for 5 pennies a piece from China and sells them for 50  pence or a pound, in the UK. So might as well get them straight fro China for much less., if I can find a seller.

Price on that site are still reasonable though, would make a repair economically viable (depending on how much they charge for shipping...), ASSUMING one ca know for sure what lenght he needs, so that he doesn't have to buy half a dozen of them of various size, hoping one of them would fit.

So that's my next question : how do you determine what lenght you need ? Measuring the old belt might not be reliable as it's tired and stretched, eh ?
Measuring the inside lengh of the belt, by wrapping a piece of string around the two wheels ?  But then, say, you measure 100mm. You would need a belt that's a bit SHORTER than 100mm, so that it makes good contact, has some springiness/elasticity, does not slip etc... no ?

So, is there a rule of thumb to determine that ? Like, I don't know... buy a belt that's 10 or 20% shorter than the measured length ?

Point is, how to be 100% sure what length you need... so that you know that if you pay shipping for one single belt... at least you are guaranteed that the money is well spent and the belt will work well.

Shakal may have a French / local seller in Frog land ? Or an address on the interweb other than the UK so we don't have to pay import taxes and god knows what taxes now apply ?!

Found the service manual, let's see how the carousel and disc detection work...

 

Offline Gyro

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Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #123 on: May 13, 2021, 05:49:54 pm »
Ha yes, belt length is a tricky one. There are all sorts of calculators for V-belts (the power transmission kind where the belt runs on the inner sides of the pulleys rather than the bottom of the groove), these usually have tensioners too.

I found a lot of hits for 'belt length', most of them as the above, but there are others from spares suppliers, eg. https://www.turntableneedles.com/How_to_measure_find_right_turntable_tape_player_rubber_drive_belt

With relatively low loads and stretchy belts there probably a reasonable amount of leeway. The link above mentions 3-5% shorter than the belt path. Maybe use cotton rather than string to ensure that you get to the bottom of the groove.  If too tight, it might cause additional wear and friction but probably not failure. I don't know if, or how quickly, a tight belt might stretch to a more comfortable fit.


P.S. Belt kits do seem to be available on ebay: eg. (obviously a UK one) https://www.ebay.co.uk/itm/402580537942.
« Last Edit: May 13, 2021, 06:01:55 pm 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 #124 on: May 13, 2021, 06:00:46 pm »
Already making progress !  8)

Service manual pretends that if you short some test point on the main board, to ground, it forces the unit to play a CD.  Does not say whether that requires the tray to be present and connected up, though....

So what the heck, let's give it a try !  I removed the tray, disconnected its cable altogether. 100% out of the way.
Grabbed a test lead, connected that test point to ground, well, the chassis.

Shoved a CD inside the CDM, clamped it by hand, turning the loading gear manually.

Then I powered up the beast and crossed fingers and toes... SUCCESS !!!

The player indeed plays the CD, not bothered in the slightest by the absence of the changer mechanism !
Plays just fine, no skipping, detects the CD promptly, can change tracks no problem.
This player works just fine !

So that's great. Now I am 100% sure that the problem lies 100% in the changer mechanism, not the player per se. So I can rule out the player core, it works like a charm.
That means it also worth trying to fix this carousel issue, because I now know that once fixed, there won't be more troubles down the line.

Me happy   :)

So let's see what's wrong with this changer...


« Last Edit: May 13, 2021, 06:15:31 pm by Vince »
 


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