Fisher CR-5125 - Page 9

ELECTRICAL ADJUSTMENTS
REQUIRED EQUIPMENT
VTVM
Frequency Counter
Audio Signal Generator
Attenuator
Dummy Load (47 k-ohm)
Dual-phenomenon Synchroscope
Test Tapes
* 3kHz test tape (Example: TEAC MTT-111) for Tape
Speed Adjustment
* 10kHz test tape (Example: TEAC MTT-114) for Head.
Azimuth Adjustment
* Test Tape for Dolby Level Calibration (Example: TEAC
MTT-150) in Playback Gain Adjustment
® Test Tapes for recording and playback operations
* Norma! Tape (Example: BASF TP-18LHS T308S)
Ferrichrome Tape (Example: SONY DUAD C-60)
* Chromium Dioxide Tape (Example: BASF TP-18CrO2
C401R)
@ Test Tapes for Tape Running Condition Adjustment
* TDK SA C-90
* MAXELL UDXLII C-90
@ Alignment Tool
Prior to the Electrical Adjustments, set the unit and the
measuring instruments as follows:
*
Dolby FM Switch .......... 0.0.00. 00 00 eee OFF
* Dolby NR Switch ......02..2... 02.00.0000 ee OFF
* Bias Switch. ...........200000- ee ee LOW
* Equalizer Switch ..............00000ee NORMAL
* Input Select Switch 2... ..... 0.00000 eee LINE
* Monitor Switch... 0.0.0... 00. cee ee ee ee TAPE
* Audio Signal Generator............. 1kHz0dB,1V
NOTE:
The Electrical Adjustments should be performed in the
order as below.
TAPE SPEED ADJUSTMENT
1. Remove the Cover from the unit and connect a frequency
counter to the left or right channel:-LINE OUT as illustrated.
LINE OUT
PLAY BACK
Frequency Counter
3 kHz (+5 Hz)
2. Play back a 3kHz test tape (Example: TEAC MTT-111).
Then, adjust the potentiometer inside capstan motor by
turning it while the test tape is being played back until the
frequency counter reading becomes 3 kHz (+5 Hz).
Em
HEAD AZIMUTH & TAPE RUNNING CONDITION
ADJUSTMENT
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Prepare for the two test tapes as described below for the
Tape Running Condition Adjustment.
We recommend “TDK SA C-90 and MAXELL UDXLII C-90
cassette tapes’’ for this adjustment.
Cassette
Connect a dualtrace synchroscope to both Left and Right
channels of LINE OUT as illustrated. Then, set the
synchroscope as follows:
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* “SOURCE 42... woh owe as INT (internal), CH1 or CH2
* SWEEP’ MODE® 3 <: ceed cs eae os AUTO (automatic)
Synchroscope
Dummy Load
LINE OUT
PLAY BACK
NOTE:
Adjust the field on the synchroscope with the VOLT. ADJ.
and TIME ADJ.
Remove the Head Cover from the unit. Then, remove the
Pinch Roller of the supply side by unscrewing the adjusting
nut.