Help requested with reading Marantz service manual

[sanjeev]

I am trying to mod my Marantz 6000 OSE CD player and am trying to add a new regulated power supply for the SAA7372 chip. I am having trouble figuring out all the places where the 5V supply is coming to this chip. What are the signals +5A, +5B etc.?

The manual is on http://members.quicknet.nl/ra.vdsteen/index_en.html


Also, I would also like to replace the VAM1201 mechanism while I am at it. Is this easy? There is an exploded parts diagram in the manual but it is not too easy to figure out whether there is some difficult alignment issue that I might inadvertently mess up.

Thanks for any help.

[anatech]

Hi sanjeev,

What are the signals +5A, +5B etc.?

The source appears to be the +D +5 VDC. Look in A5 through A7 on that schematic. You can see they are a filtered version of +5D.

Also, I would also like to replace the VAM1201 mechanism while I am at it. Is this easy?

Wouldn't we all? No, it's not really easy to do. I recommend strongly against trying to do this.

Even if you get another transport in, you still have to figure out the gains for all the servos, plus signal filtering. Then there is the APC for the laser diode. One small error and you need a new head. There are some other issues, but suffice to say that a CDM change also means a servo board change. Then you have to make it "talk" to the system controller or it will all just sit there.

-Chris

[sanjeev]

Thanks for your reply. So should I just connect the new 5V supply at 5D, by lifting one leg of the resistor to disconnect the old supply?

By replacing VAM1201 I meant replacing it with a brand new OEM part. Would I need to replace the electronics as well?

[anatech]

Hi sanjeev,

So should I just connect the new 5V supply at 5D, by lifting one leg of the resistor to disconnect the old supply?

That would work fine. Just be careful to connect the new supply in the correct places.

By replacing VAM1201 I meant replacing it with a brand new OEM part.

Just swap it out then. There are no adjustments that can be made (not a good thing). Make sure you find the RF test point and look at that signal before and after. These Philips transports are not very good, or consistent. I have had bad new ones. Make sure the RF (or eye) pattern is as clear and steady (small jitter) with an amplitude that is also steady and as high as the original one at the very least.

The procedure is pretty straight forward. Just make sure you work cleanly. Watch out for debris, grease where it shouldn't be and possible plastic bits. The lens must be kept clean. Also, clean the surfaces of the CD clamping system. I would check the original transport for these defects before you exchange them.

-Chris