NOTES:
 

1. The "target" back-tension in PLAY is 8 cm/gms, not to exceed 10 cm/gms.  Using the longest DTRS tape possible, set the tension spring to minimum, then adjust the tension arm to be in the designated region at the head of the tape.  Some tapes have uneven tension, so it is important to pay close attention as the tension arm swings back and forth. If the Tension Arm approaches the Impedance Roller, do not let it go beyond the designated region. After acheiving this goal, the arm may swing away from the Impedance Roller and beyond the designated area, in which case it is acceptable.  Only after meeting these requirements is it ok to go back to the tension tape and simply observe the values.  If the supply tension is above 8 cm/gms, replace the back tension felt.  Repeat the proceedure.  It the tension exceeds 8 cm/gms then stretch three or four coils of the back tension spring. New heads need only minimal tension (8 cm/gms).  Older heads may need more (10 cm/gms).  Running a worn head at minimal tension will give a clue as to home much life remains, especially at the beginning and end of a tape (the first and last 5 minutes as observed via the RF envelope).
2. Forward (Play) Tension has a wide tolerance (as shown), but the most important parameter is "smoothness," as the capstan servo does not tolerate irregularity well.  To achieve this goal may require trying several reel tables because they are not at all consistent.
3. In all modes, put your ear to the loading port and listend for a "wacka-wacka," washing mashine sound.  This indicates friction in the clutches, causing poor servo lock in Play mode and excess tension across the heads in reverse shuttle mode.  The latter can be double or more, the most potentialy damaging problem causing premature head failure. Monitor tension often.

It is always recommended to check the RF envelope using both the TEAC test tape as well as the Sony test tape.  The latter is only possible on a DA-88.  Getting a machine to agree with both tapes may be a challenge.  Lower tension settings reveal more problems and it is my belief that higher settings from the factory were used to "fix" problems and in some cases, cause premature head failure.

Once satisfied with the alignment, make tapes in all machines.  Be sure to include the machine's serial number on each tape.  Try each tape in all the other machines.  At minimum, check the error rate using the machine's internal "display" as per meters #1 and #2.  To be really certain of compatiblity, always check the RF envelope as well checking Error Rate via the external counter.

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