#model224

. . Fixing an old #LexiconPro #Model224 which does not start-up anymore (con't) . So, now's the time has finally come to power on the restored M224... Watch out folks! Are you ready? This is the final countdown: 5, 4, 3, 2... 1!!! . AND IT'S WORKING, AGAIN!!!!! HURRAY!!!!!! 😍😍😍😍😍☺️☺️☺️☺️☺️ . I should even add that it's working like a charm, isn't it? 😊👌👌👌❤️ So, it definitely looks like the M224 is fixed ❤️ . And the connoisseurs will have recognized the Voice (and sound examples) of the Master of Sound and Musical Research: the Great Pierre Schaeffer (1910-1995), in his quintessential, seminal recording "Solfège de l'objet sonore" (1967) ❤️ . #Lexicon #M224 #LexiconM224 #Lexicon224 #Lexicon224DigitalReverberator #DigitalReverberator #VintageDigitalReverb #EarlyDigital #Repair #VintageElectronicsRepair #VintageProAudioEquipment #StudioPiscineATokyo #PiscineATokyo #TheGoodDoctorPrager #LeBonDocteurPrager https://www.instagram.com/p/Bus-Orao9EE/?utm_source=ig_tumblr_share&igshid=zg57c6va1dac

. . Fixing an old #LexiconPro #Model224 which does not start-up anymore (con't) . While I was dusting the boards and cleaning their edge connectors (which were dirty like hell!), I decided to check all of the linear ICs on both the Analog Inputs and Analog Outputs PCBs... . Found out that the FOUR LF356 single op-amps that are at the very end of the audio signal path (right before the output transformers) were ALL toasted!!! Not surprisingly though, as not only this particular model of IC frequently goes bad when it's over 20-30 years of age, but also because, in the M224 signal path, these very ones are responsible for boosting the current of the analog output in a push-pull circuit (with the aid of two complementary, medium power transistors)... . Next and LAST step, for sure: powering the whole system on and testing it with audio signals 😉 . #Lexicon #M224 #LexiconM224 #Lexicon224 #Lexicon224DigitalReverberator #DigitalReverberator #VintageDigitalReverb #EarlyDigital #Repair #VintageElectronicsRepair #VintageProAudioEquipment #StudioPiscineATokyo #PiscineATokyo #TheGoodDoctorPrager #LeBonDocteurPrager https://www.instagram.com/p/Bus5MMfl2cT/?utm_source=ig_tumblr_share&igshid=16u436murgzgq

. . Fixing an old #LexiconPro #Model224 which does not start-up anymore (con't) . Before reconnecting the remote head and testing it, there are still three things to do... . Thrird (and last), cleaning of the Remote Head itself was required, prior to reconnecting it to the mainframe. And in case you doubt that, just compare the first picture (after cleaning) to the second one (taken before)! 😉👍👌😊😍☺️ . So, the whole system is now completely ready for being fired up all at once... and see if it eventually boots up fine, or not! 😨😊 . Stay tuned... 😉 . #Lexicon #M224 #LexiconM224 #Lexicon224 #Lexicon224DigitalReverberator #DigitalReverberator #VintageDigitalReverb #EarlyDigital #Repair #VintageElectronicsRepair #VintageProAudioEquipment #StudioPiscineATokyo #PiscineATokyo #TheGoodDoctorPrager #LeBonDocteurPrager https://www.instagram.com/p/BusgVbul6Vd/?utm_source=ig_tumblr_share&igshid=ivzj6l8ajyit

. . Fixing an old #LexiconPro #Model224 which does not start-up anymore (con't) . Before reconnecting the remote head and testing it, there are still three things to do... . Second, refurbishment of the original, simple PSU section (rectifying of the 10Vac from the power transformer and on-board +5V regulation) on the lower board of the Remote Head. . Second picture shows obvious signs of tired diodes because of overheating; brown part of the left-hand, big axial cap says the same; and most of the thermal paste of the 7805 had dried 😪 . First picture was taken after replacement of the critical components of this circuit 👌😊 . #Lexicon #M224 #LexiconM224 #Lexicon224 #Lexicon224DigitalReverberator #DigitalReverberator #VintageDigitalReverb #EarlyDigital #Repair #VintageElectronicsRepair #VintageProAudioEquipment #StudioPiscineATokyo #PiscineATokyo #TheGoodDoctorPrager #LeBonDocteurPrager https://www.instagram.com/p/Bur-TLfFkuv/?utm_source=ig_tumblr_share&igshid=1n6ik6elidep5

. . Fixing an old #LexiconPro #Model224 which does not start-up anymore (con't) . Before reconnecting the remote head and testing it, there are still three things to do... . First, replacement of the very old, leaking original batteries on the NVRAM Board with a moden Varta MemPac 😉👍 . #Lexicon #M224 #LexiconM224 #Lexicon224 #Lexicon224DigitalReverberator #DigitalReverberator #VintageDigitalReverb #EarlyDigital #Repair #VintageElectronicsRepair #VintageProAudioEquipment #StudioPiscineATokyo #PiscineATokyo #TheGoodDoctorPrager #LeBonDocteurPrager https://www.instagram.com/p/Bur8l-KldY4/?utm_source=ig_tumblr_share&igshid=jk6dylflw124

. . Fixing an old #LexiconPro #Model224 which does not start-up anymore (con't) . Restoring the PSU section, step five (last but not least!): testing the restored and refurbished entire PSU. . Part two (the last one): 224 powered on, still no remote connected but all boards now plugged in: each of the six main supply rails registers within spec, and DC waveform is steady as can be! 👍👍👍😍😍😍😊😊😊 . +5V is at +4.96V / -5V is at -5.07V / +12V is at +12.0V / -12V is at -12.2V / +15V is at +15.3V / and -15V is at -15.3V. All fine, then! 👌 . Guess now's the time to reconnect the remote head and see if the CPU finally starts up fine... which I hope it will!!!! 🙏🙏🙏 . #Lexicon #M224 #LexiconM224 #Lexicon224 #Lexicon224DigitalReverberator #DigitalReverberator #VintageDigitalReverb #EarlyDigital #Repair #VintageElectronicsRepair #VintageProAudioEquipment #StudioPiscineATokyo #PiscineATokyo #TheGoodDoctorPrager #LeBonDocteurPrager https://www.instagram.com/p/BurDx9qFs3H/?utm_source=ig_tumblr_share&igshid=xl95dihnsd23

. . Fixing an old #LexiconPro #Model224 which does not start-up anymore (con't) . Last views of the reinstalled PSU before closing the lid. . Even the plexi window protecting the P.S.#1 Board from the user has been cleaned 😉 . ...but the question still remains: will the unit boot up properly, now the PSU has been wholly refurbished? 🤔🤔🤔🤔🤔 . #Lexicon #M224 #LexiconM224 #Lexicon224 #Lexicon224DigitalReverberator #DigitalReverberator #VintageDigitalReverb #EarlyDigital #Repair #VintageElectronicsRepair #VintageProAudioEquipment #StudioPiscineATokyo #PiscineATokyo #TheGoodDoctorPrager #LeBonDocteurPrager https://www.instagram.com/p/BuqvpUolH87/?utm_source=ig_tumblr_share&igshid=mm0y1jqek0dt

. . Fixing an old #LexiconPro #Model224 which does not start-up anymore (con't) . No wonder the PSU section had issues: just a look at the underside of the top lid clearly shows that this very unit had (perharps often) heated too much, if not overheated sometimes... 😱😱😱 . Second picture is the same top lid after thorough cleaning ☺️👌 . #Lexicon #M224 #LexiconM224 #Lexicon224 #Lexicon224DigitalReverberator #DigitalReverberator #VintageDigitalReverb #EarlyDigital #Repair #VintageElectronicsRepair #VintageProAudioEquipment #StudioPiscineATokyo #PiscineATokyo #TheGoodDoctorPrager #LeBonDocteurPrager https://www.instagram.com/p/BuqZ6gIFr2P/?utm_source=ig_tumblr_share&igshid=q1fiahz6i4st