Philips CD304 MK2 help please

[tubee]

Hi all

I modified 304 mk2:

*Kwak 7 (in Xin of saa7210 AND 7220), divider to 1541, dem-reclock
*better coupling caps
*OPA2132opamps (thanks ECdesigns!)
*removed muting transistors
*new solid RCA chassisconnectors
*replaced allmost all lytics
*some beads in PS, Byv diodes
*47 ohm stopping resistors here and there between 7210 and 7220.
*Spdif 74ls74 removed, i want there a RS422 transmitter as dig-out driver with SVHS connector(thanks again EC!)

Now when i start it up(play) the cd is reading, and then stops. Dispaly says nothing then, no track info. Only open-close works of drawer.
u processors are checked, all connections, voltages/regulators are allright.

In service loop "B" the disc can be played, music hearable on output and headphone. Track selection is done by moving laser arm itself. Sounds good, did mods not for nothing. Replacing original cristal and so on doesn't change problem. A lot of control-frequencies seems allright on scope.

My thinking is that the subcode data is readed, but doesn't get a feedback to servo micro processor. Anyone here a clue where i have to search? Thanks.

pict. shows added kwak in middle of player(sorry for slight defocus, no opt. zoom)

[tubee]

Dispite 49 views no-one responded. Doesn't matter, fixed it myself this time.

Spdif 74ls74 removed

This was the reason: one 1/2 of this Flip flop regulates the subcode data to uprocessor back again!
This ignorant thinking of me! But glad it works again.

[a333bt]

Originally posted by tubee
Hi all

I modified 304 mk2:

*Kwak 7 (in Xin of saa7210 AND 7220), divider to 1541, dem-reclock
*better coupling caps
*OPA2132opamps (thanks ECdesigns!)
*removed muting transistors
*new solid RCA chassisconnectors
*replaced allmost all lytics
*some beads in PS, Byv diodes
*47 ohm stopping resistors here and there between 7210 and 7220.
*Spdif 74ls74 removed, i want there a RS422 transmitter as dig-out driver with SVHS connector(thanks again EC!)

Now when i start it up(play) the cd is reading, and then stops. Dispaly says nothing then, no track info. Only open-close works of drawer.
u processors are checked, all connections, voltages/regulators are allright.

In service loop "B" the disc can be played, music hearable on output and headphone. Track selection is done by moving laser arm itself. Sounds good, did mods not for nothing. Replacing original cristal and so on doesn't change problem. A lot of control-frequencies seems allright on scope.

My thinking is that the subcode data is readed, but doesn't get a feedback to servo micro processor. Anyone here a clue where i have to search? Thanks.

pict. shows added kwak in middle of player(sorry for slight defocus, no opt. zoom)

Hi Tubee,

i am glad you make it working.

I also bought Philips CD304 MK2.
I didnt make yet any modifications. Already sound very good.
My opinion that Philips CD304 MK2 is better performer than CD PRO2. Some said CDM1 is still best transport.
I bought CD304 MK2 for comming octal DI DAC from John (EC).

Before that i plan to make modifications like you did.
I mod i dont know what is it: divider to 1541.

Can you little explain? Is it like I2S leveler?
Did you change also 14 caps around TDA1541A?

regards, Bostjan

[tubee]

Hi Borstjan

Yes i like the CDM1 too.

The main socket is replaced too by a big 3 pole one too for cord swapping. Don't connect Gnd btw.

2 X 7 caps replaced in 100N Mkt's, for MSB in 0.47uF. Soldered direct on pcb, glued them toghether with hard plastic glue.

After the kwak is a /2 divider, done with a 74HC(T)163, this divided signal goes to Clock of 1541. When you remove SAA7220 it has to be divided by 4.

The opamp has best price/sound quality. Tried a AD823 and anothe, not sure what type. They sounded less spatial, more distorted with close recorded voices, and seemed to clip slightly.

Good luck, and beware for the brittle pcb's

[tubee]

Oh and don't pull on the wires when you remove connectors, but on the connector itself, after lifting the clip a little, otherwise a loose connection can occur. (experienced that by CD640/660 cdp's)

The Spdif from 7220 is buffered by a DS8922 is on a separate small pcb and a SVHS connector on back. Didn't listen to it yet.
I2S buffered output is better for a separate dac, and will be done in future.

If you want schematic for divider let me know.

[tubee]

Devider:

http://www.ee.latrobe.edu.au/~gt/ele...ning%20mode%22

QA = /2
QB /4
QC /8
QD /16 is ideal for dem reclock, when you add another 163 in /4 after it, then you get 176 khz for dem.

We posted at the same time!

[a333bt]

Originally posted by tubee
Oh and don't pull on the wires when you remove connectors, but on the connector itself, after lifting the clip a little, otherwise a loose connection can occur. (experienced that by CD640/660 cdp's)

The Spdif from 7220 is buffered by a DS8922 is on a separate small pcb and a SVHS connector on back. Didn't listen to it yet.
I2S buffered output is better for a separate dac, and will be done in future.

If you want schematic for divider let me know.

Hi Tubee,
thank you for kind reply.

If you have schematic for divider, yes, please.

I have also to find service manual or schematic for CD304 MKII.

regards, Bostjan

[tubee]

I have been searching for serv manual too. The SM of 14 bit 304 is more easy to get, and allmost similar besides the decoder pcb.

The divider is the diagram of 163 in "free running mode"
If you prefer a 74/74 flipflop, it could be done too, but only /2 per chip then.

regards

[beamnet]

It allways seems such a waste, buying a mk2 and then bypassing it's wonderful DAC.

As i am perfectly OK with this DAC, i started wondering: could the CD 304 mk2 be fit with a digital IN? Allso i have sevaral loose mk2 DAC boards laying around. Could these be made into a standalone DAC?

I have a USB-> I2S converter. The onboard DAC sucks, so i would love to use the mk2 DAC.

Any hints where to start?

Bas

[tubee]

When you want Nonos all you have to do is feeding the I2S data, clock (11.2896/2) and WS from the usb/i2s into the 1541 dac chip. When you want to keep SAA7220 FIR OS filter feed I2S in with 11.2896/4 clock to SAA7220. A service manual for a 1541 based player can do wonders for understanding of connections, look for example CD640 or 660. Www has a lot of schematics to offer too, read around Bas.