Pioneer CLD-2950 Laserdisc player AC3 mod

Neutrik AC3-RF jackI did an AC3 mod on my (t)rusty old Pioneer CLD-2950 PAL/NTSC Laserdisc player some time ago. I derived the circuit from http://www.laaudiofile.com/ac3mod.html and put the prototype of circuit #2 into a small plastic housing. I attached the wires to the various points on the PCB and to the new RCA jack (Neutrik) :-) I fitted on the players rear panel. There you go: Dolby AC3-RF encoded 5.1 signal which I can decode with my Pioneer VSX-859RDS AV-reveiver.

The following instructions specific to the Pioneer CLD-2950 were located on Colin Hunter's AC-3 related website which I'll continue to provide here since the page has gone away.

The following instructions come courtesy of R Larsson. The Pioneer CLD-2950 is a dual-standard (NTSC/PAL) player for the European market, very popular and probably the best of its kind available.

Remove the top cover by loosening seven screws (two on each side and three on the back).

With the front of the player pointing towards you, remove the large board on the right side of the player by unscrewing four screws, and thereby “folding” the board out to the right, and placing it in the three slots designed to hold the board during service.

The narrow board you now see is the AFMB board (Analog FM sound board). The big chip on it is the “FM-demodulator and CX-decoding” HA12127ANT. Four of the five taps are done on this board, and you have to remove it completely from the player. Loosen two screws and one clip, then pull out the four jacks. You can now take the board out.

Now place the AFMB-board so you have three jacks on the right side, and one on the left side. You can install the home made AC-3/RF-board.

Solder the wire for +5V to jumper W187 on the left side of the AFMB-board. At the same place you'll find a marking for C175 which is not mounted. Place the wire for -5V in the hole for C175's negative pin (marked with a square), and solder it on the print side of the board. Similarly, solder the wire for GND to C175's positive pin. The wire for the AFM RF-signal (as short as possible!) is solded to jumper W355, on the right side of the board.

Fasten your home made board to the AFMB-board some way (double-sided sticky tabs should suffice).

Location of the Mute-signal On the edge of the main board (the one at the bottom of the player), above IC201, marked PULSEFLOW (D/A converter) you'll find a jumper marked W206 and MUTE. You'll need to solder the mute-signal wire to this jumper, but be careful not to touch any other wires with your iron during this operation.

Finally, mount the RCA jack, the coax, C2, and after putting the boards back in place you're ready to test you're glorious new creation.

Most of the pages that are linked on laserdisc diy pages have stopped working due to formerly being hosted as aol page, geocities page or something similar. Those services have been discontinued by the respective companies. The links below are the ones I've found are still working.

It's a good thing that web archives such as the wayback machine exist. Some of the interesting laserdisc sites that have been shut down can still be accessed through the archive.

Yep, that's all. I'll be updating this site to provide more info on the AC3 mod process whenever I happen to find something.

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