Philiips cd230 - grounding of TCA0372 Laser/focus driver

[tbklbl]

Recently acquired a philips cd230 player which is using Mitsubishi MN50423FP processor working with tda1543. What suprise me is that this processor should be using the japanese i2s format(tda1543a). Hav not listen to it thu cause the CDM4/19 and the tray gear is not working.

Anyway the problem is when tracing the ground path, found that the laser and focus op-amp driver takes the ground directly from the prcocessor. My plan was to take the driver ground and make a star connection via a ferrite bead(fb) to the full-wave rectifier. Is it the correct way to treat the ground via fb? Jean Paul??

The same +/- 12 or 15?? supplies was fed to the laser/focus driver and the analog cd demphasis opamp(LM833) as shown in this thread:
analog CD de-emphasis

My plan is to :
a)non-os for the tda1543 with separate 6V regulator
b) remove all the demphasis ccts
c) add LM317 as pre-regulator for the onboard lm7805
d) add k7 clock with separate regulator
e) change all the ecap. BTW what are the shell life for those polyester cap?

Is there any other suggestion? do u guys do any thing on the resonator for the u-controller?

[Elso Kwak]

Hi tbklbl,
It does not surprise me the Japanese chip outputs Japanese format. So you have to use the TDA1543A.
In a cheap player like this supplies and ground are shared.
I would use the TDA1543A with the triple Darligton supply I posted here
http://www.diyaudio.com/forums/showt...882#post181882
and connect the KC-7 to the raw supply as it has its own regulators on board. I wouldn't use the ferrite bead as you suggested.
The resonator at the microprocessor does not influence the sound.

[guido]

Better check that Mitsu chip. If it is a decoder/filter in one, it could be impossible to go to non-os.

Greetings,

GuidoB

[Elso Kwak]

Originally posted by guido
Better check that Mitsu chip. If it is a decoder/filter in one, it could be impossible to go to non-os.

Greetings,

GuidoB

Hi Guido,
Yes you are right, digital filter on chip! I overlooked that (so many questions).

[martijn]

I know this circuit from the Philips cd604 & 614 (with remote),
but I haven't found a datasheet for this Mitsubishi chip.
Still,there are lots of 604's on the market........
Anyone out there with a datasheet?

Martijn

[jean-paul]

My plan was to take the driver ground and make a star connection via a ferrite bead(fb) to the full-wave rectifier. Is it the correct way to treat the ground via fb? Jean Paul??

Do so but leave the bead out. Beware that most circuits that use MN50423FP also make use of the internal oscillator. There is a possibility of connecting a low jitter clock instead of using the internal one. 8,4672 MHz is the one you'll need in most cases. I am looking at a Philips cdplayer now that's different from yours so please check frequency first.

In case you need the datasheet, I have it. I can mail it to you if you want it.

[tbklbl]

>It does not surprise me the Japanese chip outputs Japanese format. So you have to use the TDA1543A.

That why it's suprised u see. It was original mounted with tda1543 instead of the japanese format.

>Do so but leave the bead out. Beware that most circuits that use MN50423FP also make use of the internal oscillator. There is a possibility of connecting a low jitter clock instead of using the internal one. 8,4672 MHz is the one you'll need in most cases

There was a 8.4672MHz crystal onboard. So i presume it used a external clk.

I had tried it on a AK601 with the same Mitsubishi chip. It can output a LRclk of 44.1kHz by changing the DASEL0-3 with different pull up/down, hence it meant non-os. The only thing that bother me is that it have 2 mode that operate LRClk @ 44.1kz. From the datasheet"
1) One of the them says bypass interpolation of uncorrectable data design for non-audio application such as CD-ROM or CD-I.

2) The other is digital filter pass mode with intepolation is used external precision digital filter applications"

[martijn]

Jean-Paul,

I found a Philips 604 and a 614 this weekend.
I'm itching to try the non os mod.
Would you mail me the sheet on it's decoder/filter from Mitsubishi?
Thanks a lot! Martijn