#piscineatokyo

[piscineatokyo]

Cleaning a (first generation and somewhat abused) LARC . Keys work erratically, sliders are more or less stiff, the main screen's red filter has taken off itself, and there is not A SINGLE 4-character display that's not cracked 😱 (but as the latter would require A LOT of work to replace, let alone the price of all 12 displays 😰 that will not be changed, by customer's request) . At least, let's get all those parts clean and working 😉 . #Lexicon #LexiconPro #LARC #LexiconLARC #LexiconAlphanumericRemoteControl #VintageDigitalReverb #VintageDigitalFXBox #VintageElectronicRepair #StudioPiscineATokyo #PiscineATokyo #TheGoodDoctorPrager

[distortiondunoir]

This one is back home ! Magnifique restauration du bon docteur Prager de @piscineatokyo, un veritable travail d’orfèvre...! Ce Revox Pr99 est revenu à la vie et servira aux prochaines compositions ! ♟♣️ https://www.instagram.com/p/B1_7gxMoYMY/?igshid=1grifdfgskfp4

[piscineatokyo]

SP-12 Turbo finally restored and ready to be picked up by its owner 😊 . #Emu #EmuSystems #EmuSystemsInc #SP12 #EmuSP12 #SP12Turbo #EmuSP12Turbo #Repair #Restoration #StudioPiscineATokyo #PiscineATokyo #TheGoodDoctorPrager #LeBonDocteurPrager

[piscineatokyo]

Definitely looks like Lexicon Day today!!!!!!!! 😁 . After having repaired a PCM70 and an M480L, am I about to fix a third Lex unit in a row?... . So, I really hope this time it's the right one. Unfortunately, as I don't have a Multibus I/IEEE-796 extender board to correctly test the SBC PCB of @nautilustudio 's Lex 224's , I'm left with my own intuition and wild guesses... 🤔 . This 224 was also waiting for a solution to a strange, unpredictable behavior of the (suspected) main CPU board, where it would suddenly blank out the remote head displays and freeze the whole machine... even a cold reset (not to mention a hot one!) would not restart the unit correctly. Had to wait for some time before I could power it back on and resume normal work. . Suspected a fault in the reset circuitry, precisely in this PN2222 NPN transistor on the main CPU card, and whch is responsible for switching the RESET input of the CPU high at start-up then back off after a short while. Since I replaced it, the 224 has been on for hours without a glitch!!! 😊😊😊 . Will leave it on for some more time to see if the problem comes back or not. Just hoping it's not the D8224 CPU timer chip (that's driving the above mentioned transistor's base) that's at fault... 🤞 . #Lexicon #LexiconPro #Model224 #LexiconModel224 #M224 #LexiconM224 #VintageDigitalReverb #DigitalReverberator #M224DigitalReverberator #Fix #Repair #Restoration #VintageElectronics #Nautilustudio #StudioNautilus #StudioPiscineATokyo #PiscineATokyo #TheGoodDoctorPrager

[piscineatokyo]

HURRAYYYY!!! 😊😊😊 . So glad I just found one of the last culprits in this historical DHM89B2 owned by the world-class studios of the Groupe de recherches musicales of the french Institut national de l'audiovisuel!!! . A faulty 4066 chip had some of its transmission gates letting signals pass even though their corresponding control inputs were low... causing extreme random switching of the op-amp that compares the DC values of each "Crosspoint" potentiometers... which in turn made the switch from forward- to reverse-playing (and back) of the digital audio samples (switching that is actually controlled by the position of these very pots) extremely noisy when both pots were at more or less precisely the same value! And that would in turn produce very harsh and loud digital noises... 😱 . Now that both the 4066 IC and the comparator (a classic TL064 op-amp used as such) have both been replaced, when the pots' values are very close, switching between forward- and reverse-playing occurs either instantaneously or very quickly 👌👍😊 . #Publison #PublisonSystems #DHM89 #DHM89B2 #PublisonDHM89B2 #VintageDigitalFXBox #VintageDigitalPitchShifter #InaGRM #Ina #InstitutNationalDeLAudiovisuel #GroupeDeRecherchesMusicales #Restoration #Repair #ChipMasterCompact #ABIChipMasterCompact #DigitalICTester #PiscineATokyo #StudioPiscineATokyo #TheGoodDoctorPrager #LeBonDocteurPrager

[piscineatokyo]

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A post shared by Jonathan Prager (@piscineatokyo)

Looks like @fabcostello 's H3000 is calling in... very sick!!! 😰😰😰 . After having restored the front panel, I may now turn over to fixing the core audio issues. According to the sounds that the unit generates on its own (no analog audio signal is input), these faults seem to be caused by very low level digital logic troubles... . Let's hope I'll eventually find out the culprits! 😉 . #Eventide #H3000 #EventideH3000 #H3000UltraHarmonizer #UltraHarmonizer #EventideH3000UltraHarmonizer #VintageDigitalFXBox #VintageDigitalOutboard #Repair #PlaneteSunStudio #PlaneteSun #PlaneteSunStudioPuteaux #StudioPlaneteSun #StudioPlaneteSunPuteaux #PlaneteSunPuteaux #StudioPiscineATokyo #PiscineATokyo #TheGoodDoctorPrager

[piscineatokyo]

. . Celebrating the arrival of the new tool: goodbye Weller, hello Pace! 😊 . Hopes are high, so let's bet I won't be dissapointed by this fine looking MBT350 multi-channel rework station... ☺️ . #Pace #PaceWorldwide #PaceInc #PaceSoldering #PaceDesoldering #PaceReworkStation #MBT350 #PaceMBT350 #TimeForAChange #VintageElectronicsRepair #VintageElectronicsRestoration #VintageProAudioRepair #PiscineATokyo #StudioPiscineATokyo #TheGoodDoctorPrager #LeBonDocteurPrager https://www.instagram.com/p/Bu8cJlElf01/?utm_source=ig_tumblr_share&igshid=1ryrb9lbccuff

[piscineatokyo]

. . I think I'll settle for this one. Will be time to say goodbye to my Weller rework station then. Ten years later... . #Pace #PaceWorldwide #PaceSoldering #PaceDesoldering #PaceReworkStations #MBT350 #PaceMBT350 #TimeForAChange #VintageElectronicsRepair #VintageElectronicsRestoration #VintageProAudioRepair #PiscineATokyo #StudioPiscineATokyo #TheGoodDoctorPrager #LeBonDocteurPrager https://www.instagram.com/p/Bu3TRIyFMs-/?utm_source=ig_tumblr_share&igshid=6ceb6rdn4wqr

[piscineatokyo]

. . Clearly looks like that, for now on, the Good Doctor Prager is "grounded" (pun intended... or not!)... 😥 . My trusty Weller rework station just failed me, this time once and for all! Meaning that I definitely have to suspend all repair jobs until I get a new rework station... 😰😰😰 And that happened just at the beginning of the new H910 restoration project 😪 . BTW, I was wondering if that could be the right time to switch to Pace or Hakko... any suggestions or advise? One thing is for sure, I don't want those cheap but crappy desoldering guns from the far east 👎 . #ReworkStation #Soldering #Desoldering #DesolderingPump #Weller #WellerTools #VintageElectronicsRepair #StudioPiscineATokyo #PiscineATokyo #TheGoodDoctorPrager #LeBonDocteurPrager (à Aubervilliers) https://www.instagram.com/p/BuzS6RzFa5t/?utm_source=ig_tumblr_share&igshid=1gqjn8ltek2di

[piscineatokyo]

. . 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

[piscineatokyo]

. . 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

[piscineatokyo]

. . 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

[piscineatokyo]

. . 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

[piscineatokyo]

. . 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

[piscineatokyo]

. . 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

[piscineatokyo]

. . 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