Marantz CD273-SE Mods

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#41
Hi Phil. I have managed to find another pic where you can see the full resistor.

The colours are Red, Red, Orange, Blue, Black.

I have found a few resistors the same as this on the board, so I removed one to measure it and my multimeter won't give me a reading! Its max is 2m.

Cheers,

I wonder why the player works with the original 5v AND the new 5v supplies connected (without that resistor) but when I remove the original 5v feed and use solely the new one, the disc motor spins out of control.

Lee.
 

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#45
Hi everyone, it's me again😀

I have removed the extra reg from the saa7220 and reconnected it to the original supply. The player now works again and the output from the reg has returned to 5v.

I have inserted 660k resistor into the place where the mystery resistor went, and the reg then started reading 4.5v output. I think that the value of this resistor is critical to the correct operation of the 7220. There are other resistors of the same value as the missing one connected from the 5v rail to ground, and this seems to make the thing work ok.

The grounding scheme in this player seems very complicated to me.

my.php


Lee.
 
#48
carawu said:
Sorry Lee,

part number 2322 is 22nF@25V .... 😉
You better throw away those old 47µF ´lytic (2323) and place a good 220µF cap here.

Carsten
Click to expand...


Hi, so it's not a resistor but a capacitor then? That would explain why I couldn't measure it.

I now have a copy of the cd273 service manual which is easier to read and the part number is in fact 2323. I think the two's positions are reversed on the board, but they both connect the 5v to ground.
It looks like it was just a simple bypass cap for the elelctrolytic, which I don't need anyway.

I have a Black Gate 220uF 16v in there. I have replaced all of the 'lytics on the board, plus the 33uF on the cdm2 board.

This still leaves the question:
Why won't it work with the extra reg, lol?

Lee.
 
#50
Hi

Just to put in my 2p worth to the discussion.

I have a couple of these in my 'workshop'.
Some were fitted with the TDA1541 S instead of standard versions and had more Cerafines.

The small board is to correct a uP problem.

Sorry, I can't post a pic. as I'm somewhat away from home at the moment !!

Andy
 
#51
Hi Andy, I bought mine thinking it would contain a tda1541 s, but as far as I can tell, it's just the standard chip.

I don't suppose you could shed any light on why I have trouble feeding the saa7220 from a separate reg could you please?

ps How cold is it up your way near Norway?

Lee.
 
#52
Unfortunately not.
I do have some notes at home gleaned from this forum.There has been quite some discussion re separate regs. You could try searching for chips in the same family, cd104 etc. if there is no joy with the SAA7220.

Have you read this thread ?

http://www.diyaudio.com/forums/showthread.php?s=&threadid=75973&highlight=


64N is cold and gloomy but the severe weather of the last 2 weeks has gone for a few days so at last we can do some work.


Andy
 
#53
Thanks Andy, but I'd already read that thread. I have given up on running the 7220 from a separate tx, and have instead just added another 5v reg and tapped the supply from the existing 5v supply. It works perfectly, so it must have been a grounding issue.

I will use the spare winding on the tx to power the dac -15v or maybe the servo section under the mech.

Cheers,

Lee.

ps Anyone know where I can get a 16pf 0805 ceramic cap from? It's for my clock so I can use it in this player. I need small quantities and farnell require £20 minimum order.
 
#54
Thomo said:
Anyone know where I can get a 16pf 0805 ceramic cap from? It's for my clock so I can use it in this player. I need small quantities and farnell require £20 minimum order.
Click to expand...


I have bags of small value silver mica and ceramic caps at home !!!!

Try Ebay. There is a seller in Widnes, Auntyant2, who does bags of caps and other useful stuff. reasonable prices.


Andy
 
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