Author Topic: Vintage CD player repair : Philips CDC 486 6 disc changer.  (Read 10690 times)

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Offline shakalnokturn

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Re: Vintage CD player repair : Philips CDC 486 6 disc changer.
« Reply #25 on: December 14, 2020, 04:21:54 pm »
I second Gyro on the lasers used, I've seen bad ones on CDM 0 or CDM 1, near to no failiures on CDM 2 or CDM 4.

Start with stated capacitor, see if it behaves any better.

I'd give the spindle motor a test just in case, I've seen so many flaky ones...
My method is to tie the motor to the component tester on a Hameg scope, turn the motor very slowly by hand and check that all 3 windings are showing similar curves, finish check on a lab PSU.
Worn motors will sometimes start only if helped, or even start by themselves or not depending on the position they stopped in.
 

Offline VinceTopic starter

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Re: Vintage CD player repair : Philips CDC 486 6 disc changer.
« Reply #26 on: December 14, 2020, 06:28:59 pm »
Yep will replace that 33uF disgrace of a cap no worries. Just don't have one handy. Thousands of electrolytics in stock but... salvaged 30 years ago when I was a kid. So they must be 50 year old or so I guess... I guess I should just scrap them all, but I can resort to doing that, as I spent so many hours back in the day patiently desoldering them. They are part of my memories so I want to keep them !  ;D 

As far as brand new caps, will see what I have left over from past orders. Might have a few 10uF ones, 3 of them in parallel should do it. Else I will just go to my local shop tomorow after work, and get one. Downside is that it would be crap ones of course, no Nichicon at your small local shop of course. But for diagnostics purposes it should do it I guess.

As far as IR goes, no iPhone here, not exactly an Apple fan since the late '90s. Why wouldn't it work with my regular camera ? Who needs a smartphone anyway.


As for the spindle motor, called "turntable motor" in the manual, doesn't look like it has 3 windings ? According to the schematic (poster previously) it's a simple 2 wire motor. One pin goes to ground and the other is driven by a totem pole output, +10V at the top and -12V at the bottom. Not sure why you would need a negative voltage given that you only want to spin it in one direction ?
Maybe they apply negative voltage as a "brake", to achieve a quick stop ?
So basically it runs on 10V that's all, so should be easy to test it with the lab power supply, varying the voltage slowly up to 10V to see how easily it gets moving...

Laser-wise, there is one thing I am a bit baffled about : on the schematic, it shows that the output of the  laser is monitors by a photodiode. It's a close loop. Therefore the chip driving the Laser knows how much light the laser diode is emitting, so if it's weak or just plain dead, it would see it, and if it does, why would it try to read a disc in the first place ? Why doesn't it spit out an error code indicating a low laser output ? Maybe I am asking too much from these old drives ?.........

Got my full set of schematics printed in A3, I can work on the thing now... let's check that laser circuitry...


Oh, also : I don't have a "real" Audio CD at hand to test the drive with. So to get me going yesterday what I did is burn an audio CD on my computer, but I understand that home made CD can give mixed results depending on many factors... maybe it would be best to get hold of a real / proper audio CD before going any further... I mean, simply cleaning the lens made a difference in behaviour, so who knows what a proper audio CD might do. I would hate to spend weeks on this drive to finally come to the conclusion that it worked just fine once the lens had been clean, and that all subsequent reading problems were just due to that old drive not being happy with modern home made CD's on a 15 year old cheap super market 700MB CD, to be precise...


 

Offline Gyro

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Re: Vintage CD player repair : Philips CDC 486 6 disc changer.
« Reply #27 on: December 14, 2020, 09:04:31 pm »
There's nothing special about the spec of that cap - it doesn't need to be a low ESR one, 'ordinary' (or a good 50 year old one) should be fine.

You should stop off at a charity shop and pick up a genuine audio CD too. CDRs aren't as reflective as Aluminium pressed ones so, while the player will probably play it, the signal amplitudes won't match the values in the manual. The proper calibration CD behaves like a normal audio CD but with specially included drop-outs, pinholes and calibrated fingerprints. The player will automatically mute a data CD, whether it also spits it out in disgust depends on the specific microcontroller firmware.


P.S. Yes, later transports went from custom brushless spindle motors to ordinary brushed ones.
« Last Edit: December 14, 2020, 09:11:07 pm by Gyro »
Best Regards, Chris
 

Offline shakalnokturn

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Re: Vintage CD player repair : Philips CDC 486 6 disc changer.
« Reply #28 on: December 14, 2020, 09:59:06 pm »
I don't know about the laser monitor photodiode input, the TDA8808 datasheet doesn't give much extra information on that.

When I mentioned 3 windings on the motor, it's true there are 2 wires to supply it but usually internally on these there are 2 poles on the permanent magnet stator and 3 poles with 3 windings in a ∆ configuration on the rotor.
https://youtu.be/u_9bbW3prls

Turning the motor on the component tester you can get a comparative view of the condition of each winding and catch
unclean contacts on the commutator.
 

Offline Circlotron

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Re: Vintage CD player repair : Philips CDC 486 6 disc changer.
« Reply #29 on: December 14, 2020, 10:35:51 pm »
P.S. Yes, later transports went from custom brushless spindle motors to ordinary brushed ones.
I was about to scream "planned obsolescence!" but then I thought, would the laser wear out before the motor brushes?
 

Offline Gyro

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Re: Vintage CD player repair : Philips CDC 486 6 disc changer.
« Reply #30 on: December 15, 2020, 10:23:10 am »
Ha, my bet would be on the laser outlasting the motor. Those brushed CD motors are commodity items, used by 99% of players (DVD too) - even the high-end ones. Luckily it's easy to pull the CD hub/turntable off the shaft and push fit onto a new generic one.

There were very few of the swoing arm mechanisms that used brushless, strangely, some of them budget. My favourites are the Philips CD371 / 372 / 471 / 472 (but not 373 or 473) which used CDM2 or CDM4 transports in the brushless variant (most of the other CDM2 / CDM4 variants are brushed).

Sorry, trainspotter information!
« Last Edit: December 15, 2020, 12:23:24 pm by Gyro »
Best Regards, Chris
 

Offline shakalnokturn

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Re: Vintage CD player repair : Philips CDC 486 6 disc changer.
« Reply #31 on: December 15, 2020, 04:58:21 pm »
Same addiction here Gyro: Brushless CDM2 with TDA1541 DACs, but I'll keep a brushed CDM4 if it's free  ;D
The construction of the CDM0 and CDM1 was plastic free which of course inspires greater quality the only problem is if you do have to disassemble the swing arm for some reason, you loose your sanity in realignment.
 

Offline Gyro

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Re: Vintage CD player repair : Philips CDC 486 6 disc changer.
« Reply #32 on: December 15, 2020, 05:07:21 pm »
Glad I already stocked up on ebay!  ;D
Best Regards, Chris
 

Offline VinceTopic starter

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Re: Vintage CD player repair : Philips CDC 486 6 disc changer.
« Reply #33 on: December 15, 2020, 10:07:26 pm »
OK, just done working a few hours on the thing....

1)

Checked the +10V rail that feeds all the motors and the laser... read 15V and 700mV pk-pk of ripple ?!
Looked at the PSU schematic... the 10V rail is not regulated at all, actually it taps directly the main filter cap right after the full bridge rectifier ! So voltage level is dependent on the transformer only, and ripple is... well it is what is given the load from all the circuitry. So I guess whatever voltage level I see, is "normal"... so that means Philips calls 10V... and 15V rail. Go figure...
As for ripple, I guess it doesn't matter much for the motors, though I though it would not be wonderful for the stability of the current in the laser LED ?!... but what do I know.
Replaced the cap, 6000uF 16V.... yes, 16V cap for 15V rail... are they kidding ?  :o
In situ, the original cap read... open circuit. So replaced it. Had an almost exact replacement in my collection of 50 year old cap. It read spot on, I charged it, hold a charge very well... so I soldered it on. Absolutely no change, not even in ripple.
Tested the original cap (Nichicon...), and oh... now it does register something, and reads spot on ! Bummer...

So, red herring I guess. Still, Thumbs down to  Philips for putting a 16V filter cap on a 15V rail, and labeling in the schematics, the rail as being 10V....
That, or... the secondary winding of the transformer is partially shorted, less effective turns so higher voltage ?! I am not really in my comfort zone here, so might be talking BS sorry...
However I have to say that there is another rail that also reads quite a bit higher than its name suggests : the  " -13.. -15V " rail reads more like 18V !

So if there is indeed a defective transformer and the rial is really supposed to be 10V... then I guess a 16V rated filter cap is fine.

Hmmm.... need your view on this ! Faulty transformer or not ? :-/



2)

Tested all the components of the Laser circuitry, all fine, resistors spot on, NPN transistor tests OK (though it might be tired/weak, who knows). The pesky 33uF reads just fine at 37uF. No it's not a blue philips axial, it's a "normal" cap, a Nichicon. On the decoder/servo board there are 20 caps or so. Only 3 blue Philips, but at the other end of the board, near the bit ICs. The 17 remaining caps, in the analog part of the board we are most interested in, are all Nichicon.



3)

Spent a lot of time on the circuitry that drives the turntable motor. Fired up the scope to check waveforms all over the place, while the player was trying to load discs. I think in the last 4 hours I have ejected and loaded the cassette more times than I have in the years I used the player back in the day !  :-DD

I first tested the motor, feeding it directly with my lab power supply. I of course manually inserted a CD into the drive, from the bottom of the unit, so that the motor is loaded, in case it weak and might spin without a load but not with a load.
At the nominal 10V (assuming it is indeed 10V not 15...), motor/disc starts on the button, and after 2 or 3 seconds it has reached its full speed. at 15V it's... very strong to say the least...
So, I don't think the motor is at fault, nor a stiff spindle or any mechanical stuff.

So I then moved on to the driving circuitry. Started backwards : from the totem pole final driver then upstream.
Right there, it's fishy : the two transistors of the totem pole... both of them... their emitter-collector is shorted !  :o
Also, there collector is not directly connected to the positive and negative rails. They connect via small resistors, 4,7ohms .... and.... trouble here again !  these resistor read almost open circuit, half a meg for one, several Megs for the other !  :wtf:
Given the schematic, it should be possible to measure them in situ reliably, no ? Plus, even if not, any parasitic circuitry would cause the reading to be LOWER then nominal, can't possibly make it read HIGHER ! Never mind Megaohms !
So... doesn't look good !  Will desolder these trannies and resistors to measure them properly anyway, to be 100% sure, but I can't see how it would be any different.

Then I probed the rest of that circuitry, to see what was going on, see if the player was at least trying to spin the motor or not.

Hard to say... because it's not easy to understand how it all works, it turns out !  :-\

As you can see (see schematics posted earlier), aside from the final drive / totem pole, there is a dual op-amp, and two control signals, TC and TCMP, and some circuitry between the two op-amps. TC signal is coming from the left, issued from the decoder chip. TCMP comes from a micro. TC, appears to be a "clock" signal... well, I mean it's TTL level, periodic, 50% duty-cycle... looks like a clock. It is present at ALL times, even when the drives is idling, doing nothing at all. Frequency is about 88kHz...hmm... interesting number....could that be related to the 44kHz sampling rate of CDs ?! .....

Then this signal is turned into DC voltage via a low-pass filter, then it feed the first op-amp, set up as comparator with some hysteresis, if I am not mistaken. Then it goes through  that block of discrete components, diodes, resistors, caps... whose role escapes me 100%. The TCMP signal is mixed with that blob of component, again in some mysterious way. Then that goes to the second-op amp, set up as... an integrator or something ?!

So I probed all that area at lenght. The output of the comparator does show activity during the 2 seconds where the read head is trying to focus/ jiggles. during that same time, TCMP signal shows two nice solid 1 second long pulses, corresponding to the two movements of the head. So that's promising. At first I though it was strange to drive the motor for such short pulses, since one second, from my experiments above, is not enough to get the motor up to speed. But then I figured that the drive might not have to care : if the disc is not at the correct speed it's not a problem. As long as it's moving, it should be enough for the read head to sense a bit stream. bit stream that would make zero sense but it's not the point : if there is ANY bit stream, then it means a disc is present or else the photo-diodes would just read a constant/flat signal. Then, once the the player sees that there is a disc, it can give the motor more time to stabilize at the correct speed, and actually try to make sense of the data, and try to retrieve the TOC. So, just to say that maybe what I am seeing on the scope actually could make sense and be encouraging....

THE PROBLEM : TCMP signal output of the first op-amp looks promising, but... this results in... no signal on the input of the second op-amp ! Zero volt, constant.  So, also nada at the output of the op-amp, so totem pole is not being driven (assuming it were not blown from to bottom that is ! ).

So I think maybe there is a bad component in that bloc of analog goodness between the two op-amps. I don't understand at all what it does exactly, how it works, doesn't help really... so I guess I will have to use brute force and just check every one of these components one by one, hoping to find a faulty one.  Also, I guess it's possible that the op-amp itself is faulty ? Maybe it's input is defective, and shorted to ground ? .. though I guess this is unlikely since the op-amp in this case doesn't even know what "ground" is, doesn't mean anything to it, since it's powered by symmetrical supply.



4)

Laser power adjustment : I noticed that the trimmer (wired as an adjustable resistor, not a pot) that adjusts the laser output, is set pretty much all the way to one end : reads 400ohms for a 4,7k track. I don't know which around it works, so either it is set to maximum power, or to minimum... if set to minimum that might explain why the spot appears so weak to my eyes ?!
I will ask my dad if if he messed with the laser and focus trimmers....

5)

I got hold of a "proper" audio CD in place of my home made CDR ... didn't make any change, player still reacts 100% the same.


Anyway, next : will reconstruct the totem pole driver and check the bunch of components sitting between the two-op-amps.




 

Offline shakalnokturn

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Re: Vintage CD player repair : Philips CDC 486 6 disc changer.
« Reply #34 on: December 15, 2020, 11:19:49 pm »
1:
All rails do seem a little high and they were optimistic on the 6mF 16v cap, but hey after all those years it's still good!
The default mains wiring is 220V, these days in France we're often between 230 and 240V, you should be able to rewire for >220V by sending mains to pins 4/6 on transformer instead of 4/5 that should reduce secondary a little.

Transformers do short, sometimes partially, usually that results in a hot transformer with low voltages that soon self destructs. To get higher voltages on the secondary, you'd need a partial short on primary and for the shorted portion to go open circuit leaving a shorter winding, may be possible...? I doubt it.

2:
Good news!

3:
The motors never run at full rated voltage in the CD player, they're PLL'ed so the rotation speed will give the appropriate bitrate while reading, that's why a CD will spin faster on the first tracks (inner) than on the last ones (outer).
Running at lower voltages also means less torque, although I don't know how much initial voltage is allowed to get the disk moving.
These motors will run with a shorted winding, on a lab supply you'll not notice unless you know the normal current draw or monitor the current on a scope to spot the peak when defective winding is being fed.

The totem-pole output could have self-destructed through old age, PS being closer to VCEOmax, weak solders and heat... At the risk of being repetitive seeing that destroyed I'd go straight to the motor, if you're sure enough of the motor with the lab supply test, replace the totem pole and fuse resistors and I'm confident you'll be playing again for years.
Just make sure you do plenty of play/stop cycles, if once in a while you get an error and no spin you know where to double check  ;D

4:
Good idea to check with your dad.
In doubt I'll usually readjust laser power down to the minimum required to get no skipping on a used CD-R. (When a player will tolerate them, most do.)

5:
If anything else was destroyed it would be the OP-AMP itself, I doubt it though.
« Last Edit: December 15, 2020, 11:22:26 pm by shakalnokturn »
 

Offline VinceTopic starter

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Re: Vintage CD player repair : Philips CDC 486 6 disc changer.
« Reply #35 on: December 16, 2020, 10:08:46 pm »
Hey Chacal, don't be afraid to repeat yourself if you feel I have not paid sufficient attention to some of your points !

1)

So, I dug out my old Hameg scope, which is a bit broken (vertical position knob on CH1 is broken, and it's such a pain to fix that I just can't find the motivation...). Never used the component tester on this thing, so had to read the manual, don't laugh please  :-[

It could not be easier... except it's too easy to be useful : when I connect the motor to it, all I get is a vertical line, no ellipse. Well looing up close you can "imagine" there is an ellipse there, but squeezed so much on the X axis that it looks like a vertical line.
Test works though, I tried it with a few caps. Manual says taht it outputs a 8.5V sine wave in serie with 4,7K ohms.
Problem is that the X axis sensitivity is fixed, there are no scale adjustment in CT mode.

So I guess next thing is to build my own tester and use the XY mode on a scope. This way I can fine tune the sensitivity on X and Y axis to suit the motor. This way hopefully I should be able to display nice ellipses and will be able to easily spot any mismatch in the 3 ellipses/ windings. Stay tuned....


2)

I rewired the main transformer for 240V. As expected the 10V rails is now about 10% lower. Now 13,65V instead of 15V or so.
Under load, when the motors are working to swap discs, it drops to a bit below 13V.

At least it's below the 16V rating of the filter cap so it can only be a good thing.
I am still concerned about the huge ripple voltage though ! 0.7Vpp for a 13V rail, feeding the laser diode that I though (from what you all said), required accurate  closed loop current regulation... one would have though that you would want a stable voltage supply for starters...


3)

I desoldered the totem pole section : the pair of transistors, and the two 4,7ohms series resistors that go in their collectors.
Now I can be 100% sure of my measurements. They confirm what I measured in situ earlier :

- The resistors are a solid open circuit.
- Both transistor read fine as far as Base to Emitter and Base to Collector junctions are concerned, but somehow Collector to Emitter are a dead short, both of them. I wish I had some acid to dissolve their plastic package and investigate the die under a microscope... too curious you say ? Anyway, no acid nor microscope here, just day dreaming...

The resistors are tiny 1/4W thingies, might replace them with 1/2W ....
The transistors, BC 328 / 338. Just downloaded their datasheet, 25V 800mA, tiny plastic T092 package. Have a few brand new small transistors in stock, will have to check part numbers see if one of them might meet or exceed these specs.
Oh no, wait a minute ! Just checked my local shop's catalogue, they do have BC 328/338 in stock ! How lucky. And dirt cheap too : was 25 cents, now discounted at 6 cents for one and 13 cents for the other !  19 cents for the pair ! Will take a few of them just in case something goes wrong. A few 4,7ohms resistors as well, and I should be back in business !  :)


So tomorrow : build a custom CT to check the motor windings properly, trip to the shop and rebuilding of the totem pole driver.

Stay tuned...


 

Offline VinceTopic starter

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Re: Vintage CD player repair : Philips CDC 486 6 disc changer.
« Reply #36 on: December 16, 2020, 10:25:11 pm »
Daddy just replied to me : said, swore, that he did NOT touch ANYTHING, didn't mess around.

So, whatever the position of the focus and laser trimmer, they are as they were when left the factory.  8)

 

Offline VinceTopic starter

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Re: Vintage CD player repair : Philips CDC 486 6 disc changer.
« Reply #37 on: December 16, 2020, 10:27:48 pm »
Oh dear me..... looking at the picture I just posted above, I just realized I tested the wrong motor : cassette related motor instead of the turntable motor !  |O 

 

Offline shakalnokturn

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Re: Vintage CD player repair : Philips CDC 486 6 disc changer.
« Reply #38 on: December 16, 2020, 10:31:01 pm »
For the Hameg's component tester try the X mag. X10 you should see the the elipse well enough to not need to build anything.
The whole point is that the check is simple and efficient. Don't forget to very slowly rotate the motor while you do the test.

On rebuilding the driving stage:
Go for transistors with more beef if you must although it shouldn't be necessary.
I wouldn't recommend using larger resistors, Philips made extensive use of fusible resistors (the parallel lines and exclamation marks next to them on the schematic indicate the importance), upping their power is likely to prevent them from fusing, brings risk that they'll overheat in case the transistors fail short again, there's no other dedicated fuse upstream so that situation could also cook the transformer.

Edit:
Added photos of a random brushed DC motor I had around, the windings are good on this one, anyway it gives you a general idea of what to expect, you can see the resistance (N-E slant) and inductance elipse.
If 120° of rotation show a lot less resistance and inductance than the rest consider the motor bad.

Second photo shows poor contact on the commutator, most of the time a good spraying with contact stuff through the holes at the back of the motor and immediate exercise will solve that problem.
« Last Edit: December 16, 2020, 11:44:27 pm by shakalnokturn »
 

Offline algorithm

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Re: Vintage CD player repair : Philips CDC 486 6 disc changer.
« Reply #39 on: December 16, 2020, 11:03:11 pm »
I repaired a 6 CD changer similar to this machine a year or 2 ago. I took it apart expecting it to be something electrical, but it was all mechanical. I cleaned the lens, disassembled to where I could access all the gears, I cleaned any old dry grease I could, greased every gear. Then on the disc spindle I barely sprayed lithium grease. After that it worked. I wasnt able to read every post but if this hasnt been tried it might be worth it. Best of luck.
 

Offline Circlotron

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Re: Vintage CD player repair : Philips CDC 486 6 disc changer.
« Reply #40 on: December 17, 2020, 12:20:16 am »
To test the motor I'd just run it off a low voltage DC supply with a resistor in series, say 10 ohms, and put a scope across the resistor to see if the current ripple is reasonably consistent as each commutator segment goes by. Maybe compare it with a similar good motor as a guide to what to expect.
 

Offline shakalnokturn

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Re: Vintage CD player repair : Philips CDC 486 6 disc changer.
« Reply #41 on: December 17, 2020, 12:31:00 am »
To test the motor I'd just run it off a low voltage DC supply with a resistor in series, say 10 ohms, and put a scope across the resistor to see if the current ripple is reasonably consistent as each commutator segment goes by. Maybe compare it with a similar good motor as a guide to what to expect.

I vaguely suggested that too, but I knowing he has an old Hameg scope around I thought it was a good excuse to use it.
We all have different habits...
 
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Offline VinceTopic starter

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Re: Vintage CD player repair : Philips CDC 486 6 disc changer.
« Reply #42 on: December 17, 2020, 06:49:14 pm »
Thanks for all the info ShakalNokturn, Gyro and others...

Fusible resistors : so THAT's what they meant in the schematics with this funny notation ! I could not figure out what it meant, and failed to find the answer in the manual (maybe I am blind).

Component tester : x10 works super, thanks for the tip ! It's not even documented in the user manual ! You are better than a user manual, Hameg should hire you, well, Rodhe&Schwarz nowadays !

Now I can see the ellipse properly, yay !  8)
See pictures below. I don't see any difference whatsoever when I turn the motor to switch from one winding to the next. Yes, I was turning it veeeery slowly, but still, all ellipses look 100% identical, you just can't tell when you are switching winding.

However I do get some "crap" on the waveform, but only at the very tips / ends of the ellipse, top and bottom, and it's perfectly stable, doesn't look like random noise at all. So I poured a good dose of contact cleaner into the thing anyway, exercised it, but that didn't get rid of the crap in the slightest. I figured then that it was "normal" behaviour, at least for now, and therefore moved on and proceeded to rebuild the totem pole driver. Put the same model transistors since my local shop had them and they had been working fine for the past 30 years...

However for the fusible resistors, he didn't have much choice. The ones he had in stock were 1/2W not 1/4W, and would only go up to 2 ohms. 4,7ohms is already too high. Did Philips actually use real fusible resistors (which are wire wound from what the guy said at the shop), or did Philips use regular resistors and just labeled them as "fusible" resistor because that is their function/role in the circuit, but actually used regular carbon resistors to implement that functionality ?

Anyway, not much choice so I just bought a few 4,7ohms regular/normal carbon 1/4W resistors. At the least, it would be good enough to get me going in my diagnostic adventure.

So I replaced the transistors and "fusible" resistors.

Yes..... IT WORKS now !!!!   :-+

SUCCESS !!!   :box:

Everything works just fine, like new I am telling you !  8)

The disc starts on the button, and stops very quickly as well.
Switching from one track to the next, is fast no worries, just one second, no more no less. Just the time to quickly count "12345- 12345" and the next track is already playing, sounds good to me, it's a mechanical device after all...

Fast forward and rewind work well too.

Overall it's very responsive, no glitch no skipping no delay no nothing, it works perfectly !  :)

I then tried with my home made CDR... it works just as well as a "real" audio CD. Reliable and responsive, absolutely no difference.

So I got lucky then, it was a cheap and easy fix ! No faulty complex IC, no tired laser, no focusing problem... the stars were aligned  ;D

Thank you all for your help and advise, learned quite a bit about CD players, my first one !
If I have to fix another one day, at least I will have some rudiments about these things, I won't feel as clueless and overwhelmed as I was when I started this repair...

So happy I could fix the CD player of my childhood, and also happy to have fixed what I understand is a "special" player that the connoisseurs appreciate  :)  I know what a "swing arm" is now  ;D

Happy Vince, happy !  :D
« Last Edit: December 17, 2020, 09:11:20 pm by Vince »
 
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Offline DrG

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Re: Vintage CD player repair : Philips CDC 486 6 disc changer.
« Reply #43 on: December 17, 2020, 07:40:52 pm »
...been following this...good deal!
- Invest in science - it pays big dividends. -
 

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Re: Vintage CD player repair : Philips CDC 486 6 disc changer.
« Reply #44 on: December 18, 2020, 12:29:05 am »
 :clap:  :-+
I always enjoy your threads Vince.
Congrats mate, pop will be pleased.
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Offline shakalnokturn

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Re: Vintage CD player repair : Philips CDC 486 6 disc changer.
« Reply #45 on: December 18, 2020, 12:34:31 am »
Pleased to hear you got it back on track.

I don't know that much about fusible resistors myself, I did learn in school that they exist and know they usually stand out on schematics with an exclamation mark.
It's funny that the service manual has no specific note for this...
I think Philips used metal film fusible resistors, designed to fuse cleanly not just a random resistor with specific power and resistance rating. I suspect they have a weak point in the middle, I've always seen them blow with a small hot spot in the middle.

A couple of topics on the subject:
https://www.eevblog.com/forum/beginners/what-is-a-fuse-resistor/
https://www.eevblog.com/forum/beginners/are-metal-film-resistors-fusible-resistors/


These swing arm transports are known for being fast on track search.
On a typical CD transport you have a motor and gears for the coarse tracking which makes large track skips slowish. The fine tracking is done by slightly moving the lens horizontally (same idea as focus servo, different axis).
On the swing arm setup the arm does all the tracking action, fine and coarse, the only limitation to speed when skipping tracks is the inertia/current thrown into the coil.

Now because I was looking for a motor to illustrate the Hameg test I've dug out a Philips 70CD555/30 vintage boombox picked from the dumpster a few months ago, unfortunately  it uses a brushless motor (no, I'm actually happy about that...) so was no use for the purpose.
Tape isn't working, CD shows laser and spins during detection but no play, the lens spring seems to have taken some bashing, so there's time to spend when I find some for that.
Apparently there are fans: http://70cd555.com/
It would make a nice Li-Ion / MP3/ Bluetooth upgrade project too. Nah, I'll never ever have time for that!

Vince, you would have learnt so much more with an awkward fault  ;D

« Last Edit: December 18, 2020, 12:36:30 am by shakalnokturn »
 

Offline Gyro

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Re: Vintage CD player repair : Philips CDC 486 6 disc changer.
« Reply #46 on: December 18, 2020, 08:07:15 pm »
Congratulations Vince :-+

I should have thought to mention fusible resistors. Phillips players of that generation and earlier are full of them - one per digital IC in the series I mentioned!
Best Regards, Chris
 

Offline VinceTopic starter

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Re: Vintage CD player repair : Philips CDC 486 6 disc changer.
« Reply #47 on: December 19, 2020, 10:02:52 am »
:clap:  :-+
I always enjoy your threads Vince.
Congrats mate, pop will be pleased.


Hi Tautech !  8)

Yes the old man was very happy it turns out, even said I could KEEP the player !  :D
I was supposed to get it only after his death, but he said that since it meant so much to me, I could have it right now.
Too bad he lost the remote control, a piece of that player is gone for good now  :(  Guess I could find a replacement one but it's not the point, it would not be "my" remote control, then one I played with  back in the day. Yes I know, I am too sentimental...

Anyway, he has already replaced the Philips it with a crappy modern Sony (single) CD player he was given.

Now my living room is still a cluster fuck due to the house not being quite finished/habitable yet... so I packed all my belongings into the living room. So no space for CD player... or maybe... maybe I could put it on the top shelf of my lab along with my instruments, there is some free space available. This way I could use it to play music while I spend hours working on fixing stuff.
Just need an amplifier and some speakers, of which I know nothing. Want some decent but cheap stuff of course,no money here. Did Philips make amplifiers "matching" these swing arm CD players ? Something with the same look/industrial design ?
If not will just get some old Japanese amp, some Yamaha from the same period as the Philips. Last I looked a few years ago, these cost 50 Euros or so...

As for speakers, will try to find something local so I can hopefully test them before buying, in case some moron would dare to ship defective speakers....

« Last Edit: December 19, 2020, 10:34:32 am by Vince »
 

Offline VinceTopic starter

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Re: Vintage CD player repair : Philips CDC 486 6 disc changer.
« Reply #48 on: December 19, 2020, 10:29:26 am »
[..]  I've dug out a Philips 70CD555/30 vintage boombox picked from the dumpster a few months ago,
Tape isn't working, CD shows laser and spins during detection but no play, the lens spring seems to have taken some bashing, so there's time to spend when I find some for that.
Apparently there are fans: http://70cd555.com/

FanSSS I am not sure, but at least ONE fan and you found him!  ;D
And looks like he has just as much trouble with his unit as you do with yours ! Everything involving mechanical parts is broken !


Quote
Vince, you would have learnt so much more with an awkward fault  ;D

Yeah sure ! But it was my first dive into a CD player, learning a new type of device is hard enough, I needed an easy fix to get me started ! ;D  Next repair I would be willing to take a more complicated problem... might be sooner than I thought in fact : old man said he has another Philips unit to fix !  No not a swing arm, but a cheapo combination unit he bought in 2000, so made in China this one, not in Belgium like the old swing arms.. It combines a tape player, radio/tuner, amplifier and a.... CD player of course !  ;D  He said the CD player no longer works so I could have a go at it if I wanted to ! No particular sentimental value in this one.
However it's a got a cool 4 disc carousel changer system. This allows daddy to listen to music uninterrupted for hours, which he likes. So it would still be cool to be able to fix it so dad can enjoy a changer again.
Being a "modern" china made thing, I doubt there is a service manual for this thing, so might be difficult to fix regardless of the fault it has...
 

Offline shakalnokturn

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Re: Vintage CD player repair : Philips CDC 486 6 disc changer.
« Reply #49 on: December 19, 2020, 02:35:34 pm »
If you're looking for a small Philips amp. the FA443 seems to match quite well for looks.
Then there's a few models in the FA 400 through to FA 800 series, and some PA series.
If it was me I'd just pick the first dirt-cheap quality looking broken amplifier, they're easy and fun to repair most of the time, finding replacement potentiometers can be a bit of a headache. Maybe avoid the JVC Super-A models.

You're absolutely right for the speakers: Must listen to them before buying.
Philips made some decent cabinets, their speakers were also fitted on other brands like Bang & Olufsen.
You should be able to find a decent working pair for less than 50€, I'd advise on getting 3 way rather than 2 way.
I like the French Davis Acoustics speakers usually very efficient, anything with Audax, Seas/Vifa drivers is worth it too IMHO. There's also Magnat that are not so well known and have some nice models, there's too much around too choose from really...
 


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