MellotronHop
05-15-2010, 12:27 AM
hello everyone!
i recently acquired a second tascam 688. My favorite of the tascam line. however this particular unit seems to be suffering from an odd speed warble. its fairly consistent but during playback/record the unit will suddenly drop about a whole step before speeding back up to speed.
i gave it a new belt, new pinch roller AND a new a capstan motor. Im running out of places to examine for the problem, my last hope is perhaps changing a few caps on the motor board. Which brings me to my question...
anyone w any experience w a 688...what caps on the PCB are related to the speed control of the unit. I see a smaller PCB to the left of the transport that controls the vari speed, etc. however the leads to the capstan motor are coming from the main board.. and i just dont really seem to understand the layout of the circuit since i lack the service manual.
could it be the caps? the two attenuators? perhaps the ICs? What other possibilities am i looking at here? thank you very much!
i recently acquired a second tascam 688. My favorite of the tascam line. however this particular unit seems to be suffering from an odd speed warble. its fairly consistent but during playback/record the unit will suddenly drop about a whole step before speeding back up to speed.
i gave it a new belt, new pinch roller AND a new a capstan motor. Im running out of places to examine for the problem, my last hope is perhaps changing a few caps on the motor board. Which brings me to my question...
anyone w any experience w a 688...what caps on the PCB are related to the speed control of the unit. I see a smaller PCB to the left of the transport that controls the vari speed, etc. however the leads to the capstan motor are coming from the main board.. and i just dont really seem to understand the layout of the circuit since i lack the service manual.
could it be the caps? the two attenuators? perhaps the ICs? What other possibilities am i looking at here? thank you very much!