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Conversion of CD5500 (CDM2) to CDM4 - Completed

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Menahem Yachad
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Jerusalem, Israel
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Menahem Yachad Posted: Tue, May 7 2013 12:10 PM

Hi all,

Have any of you had any experience to convert from a Philips laser CDM2 to CDM4 -11?

I have a confirmed dead CDM2 laser, with a brand-new CDM4 replacement.

I know that B&O had a complete kit, once upon a time LOL.

I've gone through the paperwork on this conversion, as I understand it, basically as follows:

On the Servo PCB, ONE poti (laser current adj) only

C2109 120nF --> 270nF

C2134 100pF - remove

C2141 390nF --> 470nF

R3106 1K  --> 4.7K Poti

R3137 56K  --> 120K SMD 1206

R3141 100K  --> 160K SMD 1206

R3144 43K  --> 39K

R3163 82 Ohm --> 15 Ohm

R3200 remains at 120K

Diode 1N4148 - Anode to IC6102 Pin5, Cathode to Ground.

Has anyone got any pointers to add, from experience, before I jump into the deep end here?

Menahem

Menahem Yachad
Top 75 Contributor
Jerusalem, Israel
Posts 1,249
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Well, I jumped in the deep end, and purchased a brand-new CDM4 from Sebastian at Justone in Germany - he has a good stock of new units, expensive, but reliable.

Firstly, the CDM4 laser is NOT physically compatible with the original CDM2 tray, so the tray must be reamed out as shown, to allow the larger CDM4 counterweight to rotate freely all the way, and enough so that at the opposite end, the laser can reach the TOC.

Basically there are 2 notches on the wall which must be removed, and the wall thinned slightly.

Don't hacksaw off the CDM4's counterweight - it will fit, but the balance will be shot.

Menahem Yachad
Top 75 Contributor
Jerusalem, Israel
Posts 1,249
OFFLINE
Bronze Member

Here is the top side, showing the leaded component changes by yellow arrows.

At the right side, is the 7910 -10V regulator mod, with associated capacitors, which gives much more stable current to the focus circuitry.

Menahem Yachad
Top 75 Contributor
Jerusalem, Israel
Posts 1,249
OFFLINE
Bronze Member

Here is the SMD side, showing the new components. All components installed in this conversion are Vishay BC-Philips, in keeping with the original specs.

It's reading the CD's, and I am monitoring voltages and the HF "cat's eye" waveform to see that all is working OK.

At the right edge, is the blue and white wire connected to R3102, which is adjusted to 50 +/-5mV at poti R3106.

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