Philips N4504/00/15 Serviceanleitung Seite 7

MECHANICAL ADJUSTMENTS AND CHECKS
N.8B.: Do not use magnetized screw drivers. Secure
screws and nuts adjusted with laquer,
code number 4822 395 30052.
Tools and measuring instruments required:
Caliper gauge
Set feeler gauge
Spring pressure meter 3-30 g 4822 395 80029
Spring pressure meter 50-500 g 4822 395 80023
Spring pressure meter 300-3000 g 4822 395 84009
Test tape 1 KHz - 13 kHz 4822 397 30014
3150 Hz, 4.75 cm/s 8222 305 11170
3150 Hz, 9.5 cm/s 8222 305 11190
3150 Hz, 19 cm/s 8222 305 11550
Multimeter
mV -meter
Double beam oscillograph
LF-generator
Wow and Flutter meter
TAPE THREADING ADJUSTMENTS
Reel disc (Fig. 6)
- The height of the reel disc should be such that the
distance between the top of the reel disc and the
mounting plate is 15,35 mm. To measure this, you
may lay a ruler with thickness A' flat on the ree!
disc. (When measuring, the reel disc spindle should
be pressed against the thrust bearing). Adjustments
to be made with screw D.
- The axial play of the reel disc (stretch C) should
lie between 0.1 and 0.2 mm. It can be adjusted
with ring B.
Pulley of the reel disc motor (Fig. 6)
- The height of the pulley should be such that it is
on the same level as the middle of the running
Surface of the belt of the reel disc. Adjustments
can be made by moving the pulley on the motor
spindle after loosening the screws E.
Tape tension controls (Fig. 7)
- The force on the pin of the tape tension feeler
should be 90-95 g just before the tape tension
feeler touches stop B. Adjustments can be made
by bending tag A.
- The time to come back to the rest position should
be 1-1.5 s. This time should be the same for both
tape tension feelers and can be adjusted by moving
ring C.
Tape guide (Fig. 8)
Check the height of the reel discs.
The erase head and the contacts for the automatic
switch-off should be fixed on the mounting plate
in the right way.
- Insert a tape and play it back
- The height of the tape guides A should be such
that the tape runs free from the guides.
The height can be adjusted with nut B.
Pressure roller (Fig. 9)
- The pressure roller should be parallel with the
capstan. Adjustments can be made by bending
the pressure roller bracket at point F.
- The axial play of the pressure roller should be
0.1-0.2 mm, to be adjusted by moving the circlip G.
CS55246
- With pressure roller magnet off, the distance
between capstan and pressure roller should be
12 mm, to be adjusted by bending tag E.
- With pressure roller magnet off, the pressure roller
should be kept from the capstan with a force of
25-30 g, to be adjusted by bending tag B.
- With pressure roller magnet pulled-on, the distance
between ring C and upper nut D should be 0.1-0.2 mm,
to be adjusted by turning the nuts D.
- With pressure roller magnet pulled-on, the pressure
roller force on the capstan should be 1,000 g + 50 g,
to be adjusted by turning the nuts A.
Capstan (Fig. 10)
- The force of the stop on the capstan should be
100-200 g, to be adjusted by bending spring C.
- The distance between oil-retaining ring B and
bearing should be 0.5-1 mm, to be adjusted by
moving the oil-retaining rings.
- The capstan bearing should be so adjusted that
the tape runs flat between capstan and pressure
roller (The tape guides should be well adjusted).
To adjust:
. Tighten screws A
. Insert a DP-tape
. Turn screw D until the tape runs through flat
between capstan and pressure roller.
. Tighten screw E to secure the adjustment.
Pressure felt (Fig. 9)
- Check the quality of the pressure felt. If it is
hard, it should be replaced. The felt is supplied
separately and should be glued on the bracket in
such a way that the gap is in the centre of the
felt.
Warning:
Take care that no glue remains on top of the felt.
The force of the felt against the recording head
should be 10: 7 g measured at the felt. Adjustments
are made by moving spring H in one of the
grooves K.
With pressure roller magnet off, the bracket of the
felt should be so far backward that the tape groove
is free.
HEADS
For optimal playback results and minimal wear of
the heads it is essential that recording and playback
heads are correctly adjusted. The tape running may
vary per recorder and also heads are manufactured
with certain tolerances. Tnis necessitates re-
adjustment of the heads on replacement.
The mechanical adjustment comprises four important
points (see Fig. 11).
a. Adjustment of the head inclination. Wrong
adjustment means that the head will wear on one
side and will also result in a poor tape-head
contact
b. Tangential adjustment. When adjusted wrongly,
the tape-head contact will be poor
c. Adjustment of the height of the head. Wrong
adjustment results in signal losses and possible
overlapping of two tracks
d. Azimuth adjustment (groove adjustment). Wrong
Azimuth adjustment means losses in the
higher frequencies