Philips cd650, Mission PCM7000 differences ?

[ash_dac]

Hi,


Does anyone know what Mission did (if anything to the cd650) to make this player?

CD650:- Philips CD650

Mission:- see attached pic


(they both have a rear toaster)


Kind regards,


Ashley.

[guido]

Hi,

Think it is obvious from the pictures.
The mission has a new output stage. seems they did not mount the standard output circuits on the main pcb (the 650 has two outputs, one on the main and one 'additionally filtered' on the separate pcb on the right.

As for the other changes:
the pcb above the main pcb in the mission contains the decoder microprocessor and some additional logic. This is a bugfix which can also be found in the 650 (mine had one, replaced it with the single microprocessor because the old broke).

the small pcb in the front on the right in the mission is most probably the powersupply for the display. It is integrated on the filter pcb in the 650. Ive done the same in my 650: removed the filter pcb and put a small pcb in for the display powersupply.

The 650 in the picture is modified btw, the caps on the mainboard are like the mission.

Interesting, what chips are on the mission pcb?

http://www.diyaudio.com/forums/attac...amp=1060669577

[ash_dac]

Hi,


Thanks for the information.

The chips on the board are:-

4 X hef4051bp

4 X ne5532 signetics

1 X hef4094


hef4094 : 8-stage shift-and-store bus register?
hef4051: 8-channel analogue multiplexer/demultiplexer

Ne5532 (op amp)

I assume most of the chips relate to the display features since some connectors run to the display board, and volume functions (which I cannot access because i'm using a Marantz remote). The player does not work with the extra pcb disconnected.

The player uses the motorola controller rather than a SAA7210. What does the 'bugfix' pcb do ?

In the Mission the Saa7220/A, and TDA1541 were originally inside but i took the TDA1541 out and put in a tda1541A S1 since they had already provided sockets.


Did you add a low jitter clock to your CD650?


Kind regards,


Ashley.

[guido]

Hi,

The cmos chips will be there for the volumecontrol and maybe even deemphasis switching (i guess).

The smallest pcb is the display powersupply (ac) and +32V for the display driver/keyboard decoder chip. Which communicates with the other controllers (two more iirc).

Yeah, mine also has no 7210 but a M4... something. Never got more info on it. No datasheet But it seems to be pincompatible.

I'm (ab)using my 650 as testmachine. Busy with a dac (2 times 1541, D1 output stage) which also has it's own clock (Tent). See the pic. But currently working on the preamp, pcb on it's way..

Dont really get the fascination for the 650, it's plastic all over... When the dac is finished it's going into a CD80

Edit: can only guess why they had to add some hardware last minute. Just know the newer versions of the 650 dont have it, there is a single processor used. Got one of them because i killed the processor in my machine and it is pincompatible with the pcb.

[tubenut]

The HFE chips I am sure do volume on the mission PCB. What does perplex me is that the audio out from the main PCB goes to the mission PCB as well. Perhaps it just loops to their headphone out but that is volume controilled 2........

BTW, my wife likes this player (though I use a Theta mostly) for its large readable display and I like the fact you can switch off the display. I hjave no original remote either but the standby button on an arcam remote switches off the display.
The mission after better diodes and 627/637 and 2604 sounds really nice and is not a huge step back from the Theta drive and DAC I use. Did no cap upgrades, just put new fresh lytics in most places and a separate reg for the SAA7220 and one oscon on its 5 V supply.

A nice machine. Majke sure the RCA with the resistor is plugged into digital out. Makes a big difference......


G

[Franz G]

I got a CD650 today, did not try it up to now but opened it.

The enclosure is a bad and weak plastic thing, it does not convice me.

But the separate audio board calls to be replaced by a tube circuit

I like this flip top transports from Philips. Overall impression about the 650: a nice base for tweaking, I think.

Two questions:

- I dont have the terminator plug for the digital out RCA. What is the resistor in the original? 75 Ohm?

- A service manual available?

Kind regards
Franz

/Edit: I've just seen, that Elso Kwak offered some schematics in another thread. I've sent him a mail, to ask for the manual.

[guido]

Hi, some thoughts: yes, **** plastic. The separate pcb contains the displaycontroller's powersupply. You need to put that on a separate (small) pcb. look at the link in post 4, the small pcb is high up in the back.

transport is cdm2, works fine since '89.

yes, 75 ohm

got the manual, but only on paper. And it's in dutch..
But i also have the schematics zipped.

mmm, who is putting in the ****
I mean c-r-a-p

[Franz G]

Hi Guido

No problem: I can read dutch!

I spent many weeks in Netherlands, in the 80ies, working for DEC, Digital Equipment Corp.

This time, I read every day dutch newspapers. But I dont try to speak it, I will never be understood

In the meantime, I got the schematics for the CD650.

Many thanks!
Franz

[carlosfm]

Originally posted by guido
The 650 in the picture is modified btw, the caps on the mainboard are like the mission.

Right.
It's much much more modified by now.

[guido]

And the winner is .........

Mind you the stuff in the pic in post 4 is also still in there (somewhere)... someday i'll get thing sorted.

Guido