Teac A-6010GSL - Overall Signal to Noise Ratio; Erase Efficiency Check

OVERALL SIGNAL TO NOISE RATIO
IMPORTANT: Clean and demagnetize the heads before proceeding.
It is extremely important that all tests described in the
proceeding paragraphs have been completed and that all controls
adjusted are left unaltered.
Thread a record test tape Scotch 203 on the unit.
. Remove the AF oscillator from the LINE IN jacks.
Place the unit in the RECORD mode with no signal applied.
NOTE: Noise readings, when taken while recording, may be
affected by the bias signal which could be leakings through.
It is therefore good practice to rewind the "no signal" rec-
coded section and take the noise reading during playback.
. Note the point on the index counter where recording begins.
Rewind the tape and play it back.
. The noise level as indicated on the test set level meter should
be listed in table.
NOTE: Bias, erase and playback amplifier noise are all included
in this measurement. All frequencies between 40 Hz and 20 kHz
are measured unweighted.
ERASE EFFICIENCY CHECK
NOTE: To measure erase efficiency, a 1 kHz band pass filter
(TEAC M204 CL filter) must be used.
Due to the high level of this signal, it is recommended that
only a short recording be made (approximately 20 seconds) to
prevent damage to the VU meter.
Apply a 1 kHz signal at 0 dB to the LINE IN jacks.
. Place the unit in record mode and record this signal.
Rewind the recording to the beginning and remove the AF oscil-
lator from the LINE IN jacks.
Place the unit in record mode and record over this portion of
tape again with no signal applied.
. Rewind the tape to the starting point. Connect the band pass
filter to the LINE OUT jacks. Connect the test set leads to
the filter.
. Play the erased portion of the tape.
. The level meter should indicate -60 dB or more on each channel.
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