cheap sony cd player

[anatech]

Hi baggins,
The measurement is made from the chassis top to the top of the disc table. You can rough check by measuring between the dust cover of the head and the top of the disc table.

Just see how close it is to a regular Sony.

-Chris

[baggins]

Ive already done that in a sense by using the finger test ,If you let the end of your finger bump over the edge formed by 2 adjacent surfaces
you would be surprised how accurate your sense of touch is .
certainly you can feel .25 mm difference so in a sense it should be in the ball park . i am still not convinced its all there does anyone know if there should be an optical turning block immediately below the focus lens?

[anatech]

Hi baggins,
You are talking about a prism aren't you? It may just be glass or plastic on an angle.

The beam must go from the laser diode to the CD pit layer and back down. Somehow reaching the pick up photo diode array. Therefore there must be a beam spitter somewhere. The laser and pick up diodes can not share the same space.

-Chris

[baggins]

I used that term because I had read it somewhere in a CD maintenance site and i thought it was common terminology I would normally have used the term Dichroic mirror to describe the function
of passing and reflecting light rays on different polarities as i read happens in the normal CD optical system.
BUT i also read that some companies had refined the optics to reduce the lens/mirror count required . the trouble is I dont know if this Thomson pickup has a reduced optical set or not and therefore whether i am looking for something thats not supposed to be there anyway.Hence the wish for the service manual - IT might reveal ALL

[anatech]

Hi baggins,

IT might reveal ALL

So true ....

But not always. I like your term "Dichroic mirror". That I understand.

-Chris

[Nigel Goodwin]

Originally posted by baggins
the trouble is I dont know if this Thomson pickup has a reduced optical set or not and therefore whether i am looking for something thats not supposed to be there anyway.Hence the wish for the service manual - IT might reveal ALL

I'm afraid you have an extremely hopeful idea of what is provided in service manuals. As I mentioned earlier, the Sony manual merely shows the CD mech as a block, although there is a circuit diagram of it. In the probably impossible event of you obtaining a manual from whoever actually makes the mech (and to be honest Thompson doesn't sound likely!), I doubt it would tell you anything more.

[anatech]

After looking at the service manual, I see that this CD assembly is viewed as a foreign body by Sony. Not terribly surprising.

So measure the table height and then try and move it if it seems to be out of position.

-Chris

[dce]

chris

yes you are correct.
Try to measure the height.
let us know what will happen

[baggins]

Danny has kindly sent me the manual ,but it does not enlighten me ,as suspected by the cynics here . ha ha

The cd module is just a block and apart from -check the lasers working and seeking - thats about it !

I have set the platform to about 0.5 to 0.75mm above the plastic dust cover as this seems to be about the norm but i,m still getting
NO DISK on the display after the seek sequence is over.

I think it may have consigned itself to a receiver with tape cassette.
i cannot find any further info on google.

[anatech]

Hi baggins,
The good news is this.

If you find a mech cheap, you just have to install it (measure first). No adjustments.

-Chris