Denon DR-F7 - Mechanism Section Adjustments

ADJUSTING AND CHECKING ΤΗΕ MECHANISM SECTION
1. Replacing the Pinch Roller 31
Before replacing the pinch roller, clean the tape contact
surface of the pinch roller and the capstan shaft 30.
Most causes of poor tape transport can be traced to dirty
pinch rollers and capstan shafts.
By removing the pinch roller spring 33 and the 2.5E ring
139 , the pinch roller 31 can be taken out, along with
the pressure bracket. When assembling, always insert the
pressure bracket 32 shaft into the long hole of the con-
necting lever 11 on the back side of the mechanism
chassis 1.
After replacing, run a pad-less C-90 tape to check for tape
curls at the tape guide section of the head.
2. Checking the Pressure Force of the Pinch
Roller
In the playback mode, hook a dial tension meter (500 g)
onto the bracket at the center of the pinch roller. After
separating the pinch roller from the capstan shaft, allow
the pinch roller to contact the capstan shaft again. Check
to make sure the dial tension meter reads between 375-
475 g when the pinch roller starts to rotate. If it is not
within the normal range, replace the pinch roller spring.
Note: In the playback mode, check to make sure that there
is a gap of more than 0.5 mm between the pinch
roller bracket 31 and the pressure bracket 32.
0.5mm
|
pressure bracket |
pinch roller bracket
3. Replacing the Record/Playback Head
* Before replacing, remove the mechanism unit from the
chassis.
(1) How to remove the Β/Ρ HEAD.
1) When the R/P HEAD holding screw 102 is taken
out, be careful as the CORD CLAMPERS 49 and
47 as well as the 3T-LUG with the wire will come
off.
Next, take out the azimuth adjustment NUT 159
and the height adjustment ORDER SCREW 39
loosening them alternately.
If they are not lodsened alternately, the R/P
HEAD base may become warped.
D
order
Screw
(85)
ΒΡ
Head
N
^
ES
Dan
v
(E M2 x 6 crs
2) By unsoldering the HEAD WIRES on the circuit
board section of the R/P HEAD, the entire R/P
HEAD can be taken off the mechanism unit.
(2) How to assemble the R/P HEAD.
Reverse the above (1) procedures for removing the R/P
HEAD.
* Solder the HEAD WIRES according to the diagram
above.
* In replacing the R/P HEAD, whenever possible, do not
remove the WIRE CLAMPER, which holds the HEAD
WIRES to the CORD CLAMPER 77. It is adjusted so
that the HEAD WIRES do not become a load during
the HEAD PLATE operations.
If the WIRE CLAMPER must be removed, after replac-
ing the R/P HEAD, check to make sure that (1) the
HEAD WIRES do not contact the pinch roller spring
during the HEAD PLATE operations; (2) the HEAD
WIRES are not creating a load at the bottom plate and
that the HEAD PLATE lowers to the required position
at the STOP mode.
4. Adjusting the R/P HEAD
(1) Height adjustments (Use the head adjusting jig M-300)
Set the M-300 tool plate on the mechanism unit; turn
the height adjustment ORDER SCREW 39 and adjust
so that the 3.8 mm measure section of the M-300 (tool
grip) can pass without contacting the tape guide of
the R/P HEAD 35.
— 43ج