Revox G 36, Service Manual

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1
Genera
l
The REVOX Series 36 has been constantly improved and kept up to date, since it was
first introduced in 1956. However, the present G still bears the same basic layout and
conception as did the original A recorder.
Compared with the preceding models, the following major innovations have been
incorporated in the REVOX G 36 recorder : Hysteresis-Synchronous Capstan motor,
VU-meters for record level control and a tape-tension switch to permit the use of all
reels from 7 inch up to 10 1/2 inch diameter.
The G 36 model is available in both 2 and 4 track versions. Identification is made by
the appropriate number being stamped on the head mounting plate, and on the upper
side of the lower chassis.
The recorder consists of an upper and lower chassis. These are joined at the rear by
means of the back panel which carries the input and output sockets, mains voltage
adjuster and fuse-holder, and at the front by means of the loudspeaker panel
mountings. The upper chassis carries the tape transport mechanism and the lower
chassis bears the power supply unit and the electronics.
All Audio Connections are led to standard phono sockets. To interconnect the
REVOX recorder with other Audio Equipment, a selection of adapter cables is
available.
2
Mechanical Description
The machine employs three motors. Two are identical and perform the wind and
tension functions. The third motor is large and drives the capstan. It is of the pole
switching variety and speed change is therefore effected electrically.
The wind motors are designed to provide pulse free torque. Back tension is applied
by electrical counter torque during the record and playback functions as well as
during wind.
The Capstan Motor is of the Hysteresis-Synchronous type, incorporating a special
design feature to prevent hunting. By switching to either the 6 or 12 pole stator
winding, the tape speed of 7 1/2 or 3 3/4 ips may be selected. The capstan drive, the
pinch roller assembly and the headblock with the tape guides are carried on one die-
cast frame. This ensures accurately parallel and permanent alignment of all major
transport elements. The coupling between motor and flywheel consists of special
silicone-rubber strips, with the whole assembly acting as a mechanical filter. A direct
slip free drive is thus achieved whilst maintaining negligible wow and flutter.
The pinch roller is held against the capstan during record and replay functions with
considerable pressure. This necessitates the use of a capstan bearing designed
specifically to withstand considerable side pressure for long periods. The pinch roller