Philips CD951 • A DAC7 (TDA1547) vs TDA1541A R1 vs SM5872 story

[Malefoda]

Need help, it's still faulty. It does the same as when I've tried it, after warm refuse or have hard times to read TOC or sometimes 1st track.
When I've changed the small cap at SAA7310 pin 29 (PLL circuit, what is that?) to a giant one the error was the same but always, even cold, maybe it's a clue. Then I've fitted back the old elcap 2.2µF.
When warm and do that a fast on/off from the main and here we go again. I'll try to change the Motor driving opamp's caps (they are still the old ones) and maybe -if I can find some infos if non polar is OK- a 2.2 film cap at pin 29 "PD/OC" of the SAA7310.
Any input weclome!

Matthieu

[Markuzz]

Originally Posted by Malefoda

I have the CD651 SM in paper, the CD950's one in pdf if needed.

So we have a dicrete circuit for the TDA1547 and have to find one for the TDA1541. I remember Simon used a (Nelson?) Pass I/V stage or something in his CD650?

What about this design from Lukasz?

Fet-ishizator

It looks interesting for the TDA1541A, only the absent of the analog filter might be a problem as I am playing in NOS mode.

[Malefoda]

Very promising,
but I'll keep this thread for the TDA1547 and will do a new one for the CD-40, you have to wait a while (Xmas if all is fine) to see it online
But I can say that's the kind of idea I was looking for, easy to built, all info provided and why not order some clean PCB for at least us?

Matthieu

[Markuzz]

Originally Posted by Malefoda

Very promising,
but I'll keep this thread for the TDA1547 and will do a new one for the CD-40, you have to wait a while (Xmas if all is fine) to see it online
But I can say that's the kind of idea I was looking for, easy to built, all info provided and why not order some clean PCB for at least us?

Matthieu

Sure thing Matthieu, when ordering PCB's count me in!

[Malefoda]

Originally Posted by Malefoda

Need help, it's still faulty. It does the same as when I've tried it, after warm refuse or have hard times to read TOC or sometimes 1st track.
When I've changed the small cap at SAA7310 pin 29 (PLL circuit, what is that?) to a giant one the error was the same but always, even cold, maybe it's a clue. Then I've fitted back the old elcap 2.2µF.
When warm and do that a fast on/off from the main and here we go again. I'll try to change the Motor driving opamp's caps (they are still the old ones) and maybe -if I can find some infos if non polar is OK- a 2.2 film cap at pin 29 "PD/OC" of the SAA7310.
Any input weclome!

Matthieu

Up!
I will try to find what can cause that, the film cap or newer ones at driver changed nothing. Defo too slow at accessing track 1 in best case, error in worst one and "loaded" message when it can't even access TOC.

[martin clark]

That PLL is fundamental to the decoder pulling the data off the disc cleanly. Perhaps see p.22 of the datasheet and try the values shown..:

http://www.acoustica.org.uk/misc/SAA7310.pdf

Non-polar or film types should be ok here; I would try a film though (no DC leakage)

If the disc reports as loaded, even if track 1 doesn't start properly, the laser is OK and it is something else failing - like the PLL lock. Making sure the disc motor circuit is performing well is a good idea, though.

[Malefoda]

Yep Martin I've checked this, but it seems to be more a random problem than this one. I did put the player in trouble but there is a real problem anyway. Like the disc motor does not spin fast enough to catch track 1 or even read the TOC sometimes, if I ask for tracks in the middle of the disc it's fine. I'll have to read the many threads about bearing, plates and such... dead CDM9 :'(
Sounds like "* Disc spins but at too slow a rate or is erratic or needs some help (weak
motor or dead spot). Reading of disc directory may be erratic. (Try
helping motor out by hand)."
I'm scared to damage the mech when having a look...

[martin clark]

The cdm9 is pretty robust IMO.

If it is the regular CDM9 (not CDM9pro with Hall-effect motor) it has a simple Mabuchi disc motor with brushes. You can unsolder the black and red wires on the bottom of it, apply 5-9v for a short moment to spin it up/clean the commutator and try again The merest drop of oil on its bearings may help.

[Malefoda]

Let me guess... some Naim stuff have CDM9
Yes it's a brush one. Nice tip for 5/9V and I will apply 9V (5 secs?) and a drop of... WD40 is nice? or Royal Purpule, it's good for rotary must be good for Mabuchi that's so annoying
Thanks for helping Sir!


I hope it is that, I hope it is that, I hope...

edit: have removed a RF-310T from old CDM12... not the same... stupid me!

[Malefoda]

I'm fishing:
CDM9 /65 problem, help needed!
If no answer in 7 days and no way to play my hundreds of CDR in normal condition I put it on eBay.
Anyway, I'll try the DOS in this weekend, just to see.

Matthieu