#chipmastercompact

. . Emergency case for @sodasound studios' #LexiconPro #M200 (cont') . After having replaced the corroded resistors and the "NMI CAL" trimmer, and after having soldered the correct battery for the job DIRECTLY onto the PCB (Lexicon even provided the board with different footprint patterns for different battery form factors! 👍), the unit finally starts up fine each time and does not randomly reboot on itself anymore 😊😊😊👌👌👌👍👍👍 . While I was at it, I checked the Z80 CPU. As it failed to pass the tests of my trusty #ChipMasterCompact #ICTester, I decided to replace it, as well as its old socket 😉 . Also took two pictures of the newly soldered components from the underside of the board... so you might just have a peek at my solder job ☺️ . #LexiconInc #LexiconM200 #Model200 #LexiconModel200 #DigitalReverberator #VintageDigitalReverb #EarlyDigital #Repair #VintageElectronicsRepair #VintageProAudioEquipment #StudiosSodasoundParis #SodasoundParis #SodasoundStudios #SodasoundStudiosParis #StudioPiscineATokyo #PiscineATokyo #TheGoodDoctorPrager #LeBonDocteurPrager https://www.instagram.com/p/BtsxOgYlfTp/?utm_source=ig_tumblr_share&igshid=1wyf1n8e6d88f

. . And the series continue... . Still working on the same #Eventide #H949 #Harmonizer (from the @melodiumstudio in Montreuil): just found a faulty 74C08 (CMOS) AND gate that was clearly damaging the clock signal going to the DA converter section of the Main output... causing a slight but hearable harmonic distortion on this output when switching to the harmonizing function, necessarily the most used one on these machines! 😨 . Upper left picture shows the two clock signals (one for each digital audio fragment needed for the pitch-shifting effect): yellow trace is the B part, blue trace is the A part. They should have been identical, except in phase (they must only alternate in time)... Upper mid picture shows the analog waveform resulting from the sample&hold process, after DA conversion (that is, a 1 kHz sine, but jagged because unfiltered): blue trace is clearly not as clean as the yellow one... 😥 Upper right picture shows the output of the op-amp that mixes both waveforms into one: no wonder that the audio output was distorted! . After replacement of the offending chip (that my trusty #ABI #ChipMasterCompact #ICTester found faulty too, see center left pic), the clocks' waveforms now look perfectly clean, and so do the the individual analog A & B outputs, as well as the blending of the two! 👌😊 . [center right pic shows the original, Harris-made MM74C08N chip, replaced with a NOS National one from 1987] . @eventideaudio @eventidefrance . #EventideInc #EventideAudio #H949Harmonizer #EventideH949 #EventideHarmonizer #EventideH949Harmonizer #VintageDigitalPitchShifter #VintageHarmonizer #VintageDigitalFXBox #EarlyDigital #Repair #Fix #ElectronicsRepair #VintageElectronicsRepair #ABIChipMasterCompact #DigitalICTester #StudioMelodium #MelodiumStudio #StudioMelodiumMontreuil #MelodiumMontreuil #StudioPiscineATokyo #PiscineATokyo #LeBonDocteurPrager #TheGoodDoctorPrager https://www.instagram.com/p/BspnW9IlM9_/?utm_source=ig_tumblr_share&igshid=19pwvhnrkjixe

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

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

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

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

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

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