Tascam DA-98HR Service Manual

Also see for DA-98HR: Setup guide Owner's manual

Tascam DA-98HR Service Manual Manual pdf 37 page image

375-5. Offset adjustment in the VCO free-runningfrequency automatic compensation circuit1. DTRS mode1) Play the MTT-88101 or MTT-88102 test tape.2) Short-circuit P401's 1 and 2 on the SYS PCB (A-HEADplaced in test condition).3) Connect an oscilloscope to TP422 on the SYS PCB, andadjust the scope range to 1V DC, 0.5 μsec.4) Adjust R439 (A-HEAD) on the SYS PCB for 2.5 V DC atTP422.5) In a similar way, short-circuit P401's 2 and 3 (B-HEADplaced in test condition), then adjust R440 (B-HEAD) for2.5 V DC at TP457.6) After adjustment is complete, release P401.Note)In 4) and 5), even if a positive-going or negative-going slightglitch is observed as shown in Fig. 5-2, it should be accept-able. However, perform adjustment to alleviate glitches asmuch as possible.2. HR mode1) Play a tape recorded in HR mode.2) Short-circuit P401's 1 and 2 on the SYS PCB (A-HEADplaced in test condition).3) Connect an oscilloscope to TP422 on the SYS PCB, andadjust the scope range to 1V DC, 0.5 μsec.4) Adjust R437 (A-HEAD) on the SYS PCB for 2.5 V DC atTP422.5) In a similar way, short-circuit P401's 2 and 3 (B-HEADplaced in test condition), then adjust R438 (B-HEAD) for2.5 V DC at TP457.6) After adjustment is complete, release P401.2.5 V0 V