How to make correct adjustment of CDM4

[Tubeee]

Hi all pro,

There are two vars(potmeter) combo with CDM-4 laser pickup system (on the pcb beneath the CDM-4), 4K7 and 22K. As I know these VARs are for the adjustment of laserdiode output and focus.

Questions are:

How to make precisely adjustment. Does anyone has related service manual?

If I change a new CDM-4, do I need to re-adjust these var to a correct value? (I think my CDM4/19 is dying)

need your kindly help....

[Cobra2]

Having nothing better to do(?), I took the old laser out of my CD-16 (CMD4-d36) and swapped the internals(laser) from a new CDM4.19.
Only the platter-motor differs (exept the metal...)

And everything works well, playing now...

Arne K

[Tubeee]

Hello Rudolf Broertjes,

I just search your previous post:
http://www.diyaudio.com/forums/showt...456#post120456

I think that's what I want to know now:

I have the adjustement procedure for tracking & focus with the two test points (50mV and 400mV).

Where is these two test points: (or which registors?)
50mV is for tracking (laserdiode output)
400mV is for focus.

Is this done by using amp-volt meter to measure specific registor and check the amp cross it?

thanks

[zygibajt]

Hi,
Any one knows where the test points for this 50mA and 400mA are?

I got the CD-player where someone turned two trimming pots all the way up!

Bartek

[Cobra2]

I guess it will be on different location in different players...
What make & model?

Arne K

[zygibajt]

There are always 22K and 4,7K pots and all the chips are usually the same.

The model in question is Marantz CD 883 but I have a couple of other ,diffrent machines and with CDM4/19 laser/drive it's always the same.

In fact this Marantz CD 883 is identical inside to the Marantz CD 65MKII ,just the same main board.

I have similar procedure for CDM 2/10.It goes ..."measure acros this resistor near that chip...and so on"

I need similar procedure for CDM 4/19

Bartek

[Bricolo]

Is the procedure the same for all CDM4 based machines?

[zygibajt]

Is the procedure the same for all CDM4 based machines?

I suppose it is.Chips and topologies are the same.

If any one knows it please share it with me.

Bartek

[rbroer]

Here you are




Designators can/will differ between several versions.

Just look for similar valued resistors on the pcb;
Many old Philips players can be measured near top left of transport.

[zygibajt]

Many thanks Rudolf