Lexicon M224X

A Lexicon rack processor whose parts documentation survives in better shape than its published story. The 224X is real, and the paper trail proves it.

Overview

The Lexicon M224X is hard to write about honestly, because the paper trail is lopsided. The service and parts documentation is unusually complete: parts lists, assembly drawings, retrofit instructions, shipping kits. The published record, at least in the sources available here, is close to silent. No production run, no original price, no independent measurements. What follows is what the documents establish.

The documentation shows the M224X was a distinct, supported product in Lexicon's line, treated as a sibling to the M224 and not a footnote. The parts lists are explicit. A 50-foot control cable, part 680-02055, is picked and added to one of two different finishing kits depending on whether the unit is an M224X (#022-03700) or an M224 (#022-03061). The same branching shows up in the 25-foot cable option, where part 680-02045 goes into kit #024-03700 for the M224X or #022-03061 for the M224. Lexicon kept separate kit numbers for each model, which is the kind of administrative detail a manufacturer only bothers with when both are in the field.

The retrofit documentation is where the M224X gets interesting. A software update to V8.1 was issued for the M224X specifically, shipped as customer literature part 070-03261, and the parts list describes it as including updated sections of the owner's manual. An owner receiving that retrofit got new firmware and a revised manual to match. That suggests the M224X was supported long enough, and by enough users, to justify the paperwork. A separate LARC retrofit instruction (070-03739) and a LARC panel-mount instruction (070-03759) appear in the LARC shipping kit alongside a 224XL owner's manual (070-03695). The M224X's remote-control ecosystem was documented as its own thing, not folded into the XL's.

The LARC shipping kit shows how these units left the factory. It includes a warranty card, a 50-foot LURCH cable (680-03525), a cassette interface cable (680-03690), a 3AG slo-blo 3-amp 250-volt fuse (440-01624), a 5×20mm slo-blo 1.6-amp fuse (440-01876), two fiber washers, two non-insulated spacers, an IC extractor (780-01925), and a clear 3×5 bag stapled to the panel-mount instruction. An IC extractor in a shipping kit says Lexicon expected a field-service-minded owner or dealer to open the lid, not a casual buyer.

The 115-volt fuse option covers the electrical side. The M224X takes the same 3AG slo-blo 3-amp 250-volt fuse as the M224 and M224XL, part 440-01624, added to chassis cage kit #023-03706 for the M224X (versus #023-03021 for the M224XL and #023-03028 for the M224). Three amps of slo-blo at 115 volts is a lot of headroom for an audio processor. The LARC kit also ships a 1.6-amp 5×20mm slo-blo for the 230-volt side, so the M224X was built for both mains standards.

The assembly drawings add a few more details. A revision dated 12-1-82 removed a fuse and added a jumper on the transition board assembly. Another revision, dated 12-2-83 under ECO 224-011982, revised the drawing. A note on one drawing says the D-type connector should be spaced 1/16 inch off the board when soldering, so the distance from the mounting flange to the PC board is 1/4 inch. Another note says that on bluelines of the drawing, a print machine setting of 5.746 should be used. These put the M224X's active documentation period in the early-to-mid 1980s.

One more piece. The timing and control board parts list identifies PC board 710-02482 as the "PC BD, HST&C, M224X." The M224X had its own timing and control board, distinct from the M224's. That is a hardware-level difference, not the same board with a different sticker.

None of this documentation says what the M224X sounded like, what it cost, how many were made, or how it was received. No period review is available in the sources consulted here, and the fact sheet is explicit that the model name does not appear in the general Lexicon company history that covers the 224, 224XL, 480L, PCM series, and 960L. So the M224X is a documented product with a thin published record. For collectors, that usually means it was built in modest numbers, or it was sold into a niche the trade press didn't follow. The documentation can't say which.

For anyone hunting one, the M224X should be judged on its own paperwork. The LARC remote, the 50-foot control cable, and the cassette interface cable are all part of the factory configuration and are the pieces most likely to go missing. The V8.1 software retrofit and its updated manual sections are worth asking about, since a unit that received the update will have documentation the earlier version didn't.

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