Alex White
New Member
My Lexicon MC-8 restoration journey
I bought this Lexicon MC-8 on eBay as “no power, for parts.” Surprisingly, when I plugged it in, it started normally. After several hours I turned it off, but later the power supply only made a repeating tick-tick sound, apparently going into protection.
One failed capacitor in the middle of the power supply caused the problem. My guess is that the very hot delivery weather temporarily helped the failing capacitor work, but after cooling down it would no longer start. I replaced that capacitor and the MC-8 worked again. Later, I replaced all electrolytic capacitors in the power supply for reliability. The original supply is the FYX600/87G-BEeb shown in the photo.
The original Itron CU20029ECPB-W1J display still worked, but had become extremely dim. I replaced it with a Noritake Itron CU20029-UW1J. The new display showed “LEXICON,” but the startup diagnostics stopped with a VFD memory error. The replacement display works visually, but apparently does not respond to the memory test exactly like the original.
New Noritake Itron CU20029-UW1J display installed and operating at 75% brightness.
The MC-8 sends diagnostic information through the second RS-232 port. I used a small passive Python script at 19200 baud, 8N1 to capture the startup messages. Holding MAIN TV and ZONE 2 TV together allowed the diagnostics to continue past the failed display test. After a cold restart, the unit became fully operational.
I also:
- Added a larger heatsink to the hot section of the main board, which measured about 131°F with the chassis open. I used 3M 8810SQ-15(10) thermal adhesive and zip ties for additional security.
- Replaced the IR receiver with a TSOP58438.
- Replaced the worn encoder with a PEC16-4225F-N0024.
- Replaced the memory battery with a Panasonic Energy BR-2325/HBN.
Previously, I used a HiFiBerry DAC2 Pro with a Raspberry Pi 5. The Lexicon sounds more natural and is easier to listen to for long periods. Was the original approximately $6,000 price justified? Considering the design, construction, processing, and sound quality, I think it was. As a music preamp and DAC today, it is still an excellent machine.
I will also attach the Python script used to capture the internal boot diagnostic messages.
Has anyone tried modifying the MC-8 firmware to skip the display-memory test at cold start? My new display works fine once I press MAIN TV + ZONE 2 TV to continue.