Electrical Adjustments; Sensor Check; Tape Path Fine Adjustments; Torque Check - Sony DTC-670 Service Manual

I. ELECTRICALADJUSTMENTS
d Sensor Check
form the following adjustment when the holderhas been removed
lan ofthe mechanism deck section replaced.
eck Procedure:
Connect an oscilloscope to the test land SE (in the S side) and TE
(in the T side) of the main board.
Actuate the testmode (main. servo), mountan end sensorcassette
and effect the STOP (l) mode.
Check that p-p values ofwaveform ofthe oscilloscope sarisfy the
following.
ûD Torque Check
reck Procedure:
hrt the set into the test mode (main. servo) and load the F1ilD
torque meter T'W-71 3l (8-909-708-7 U,
Put the set inûo the PLAY (>) mode.
Confirm ttrat the FWD torqrrc value (ake-up side rcwinding
torque) is between l0 - 20 g.cm (0. t4 - 0.æ oz.inch).
Confirm thatthe value indicatedby the orque meteris maintained
for one ftrll cycle.
VD BadrTonsion Chedr and Adiçtment
rcck prccrdure:
Put thc set into ûre æst mode (main . sewo) and load the FWD
torque meær TW-71 3 I (8-909-708-71)
hrt the set into the PLAY (>) mode.
Confirm ttrat the back ænsion (supply side) is bctween 5 - 6 g.cm
(0.07 -O.09 oz-inch).
If this is not satisfre4 adjust back tension by rotating the FWD
back ænsion adjustnett screw equipped on the side surface of the
mechanical deck After completion of adjusting, be sure to apply
screw lock.
Conlirm that value indicated by the torque meter is maintained for
one full cycle.
b tighten (clockwise) - back tension becomes larger'
b loosen (counterclockwise) -
back tension becomes smaller.
Tape Path Fine Adfustrnents {x 1.5 FWD Mode}
Perform the following adjusunent when the dnrm has been replaced.
Adjustment Procedure :
l. Connect ur oscilloscope CH-l to 1P (PBRD and CH-2 ro TP
(StilP) on the main board.
2. Put the set into the test mode (main . servo) and load test tape TY-
72s2 (8-909-822-û).
3. Press the AMS (DD{) key.
Each part of switches on Test Mode.
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4. With the REC MODE switch set to STANDARD (ATF: OFD
and the TIMER switch set to PLAY or REC (OFFSET: + or -),
frne adjustthe Sl and Tl guides so that the oscilloscope RF signal
waveform rçmains the same whcn highJow is rcpeaæd.
* Finish the adjustment by screwing in.
5. Check the RF signal wavcform with the REC MODE switch set
to LONG (ATF: ON) and the TIMER switch set to PLAY orREC
(OFFSET: + or-).
OK
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6. Check the RF signal waveform with the REC MODE switch set
to LONG (ATF: ON) and the TIMER switch set to PLAY or REC
(OFFSET:0).
(l) Confrm theat the RF signal Ùaveform peak value (B) is 60
mV or more,
: Æ l ,
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7