#digitalictester

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

Another SP1200 fixed! 😊 . This time, one of the two main binary counters in the master clock section was bad, making sampling new sounds corrupting sounds already in memory... yeah I know, it looks pretty pervert indeed! 😞 . That's actually the usual burden of digital logic issues: one small fault can (often indirectly!) give rise to what seems like complex problems to solve... think I'm getting used to that 😉 . #Emu #EmuInc #SP1200 #EmuSP1200 #VintageSamplingPercussionSystem #VintageDrumMachine #DigitalDrumMachine #Repair #ChipMasterCompact #ABIChipMasterCompact #DigitalICTester #StudioPiscineATokyo #PiscineATokyo #TheGoodDoctorPrager

Hard-To-Fix-Faulty-H910 #3: just found another bad guy: this time a malfunctioning 74C00 quad 2-input NAND gate... #Eventide #H910 #EventideH910 #Harmonizer #H910Harmonizer #EventideHarmonizer #VintageDigitalPitchShifter #VintageHarmonizer #VintageDigitalFXBox #EarlyDigital #Repair #StudioKadence #ABI #ChipMasterCompact #ABIChipMasterCompact #DigitalICTester #StudioPiscineATokyo #TheGoodDoctorPrager

Hard-To-Fix-Faulty-H910 #3: already found one 74C193 Synchronous 4-Bit Up/Down Binary Counter dead! #Eventide #H910 #EventideH910 #Harmonizer #H910Harmonizer #EventideHarmonizer #VintageDigitalPitchShifter #VintageHarmonizer #VintageDigitalFXBox #EarlyDigital #Repair #StudioKadence #ABI #ChipMasterCompact #ABIChipMasterCompact #DigitalICTester #StudioPiscineATokyo #TheGoodDoctorPrager