Uher 22 hi fi Special Service Manual

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22 Hi-Fi Special
24 Hi-Fi Special

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22 Hi-Fi Special
24 Hi-Fi Special

l/003/865

Contents
Page
1. Transport Mechanism ......................... l
2. Clutches ................................ 1
2.1 Checking the Clutches .................. 2
2.2 Adjusting the Heighht of the Clutches ........... 2
2.3 Checking and Adjusting the Clutch in the Drive Wheel . . . 2
2,31 Checking the take-up Pull of the right-hand Clutch ..... 2
2,82 Checking and Adjusting the Pressure between the
Drive Wheel and the Lower Section of the Clutch ..... 2
3. Brakes ................................ 3
3.1 Checking and Adjusting the Clutch Brakes ......... 3
3.2V Checking and Adjusting the Brakes of the Braking Discs . . 3
4. Tape Feed ............................... 3
4.1 Measuring the Feed Pull 3
4.2 Adjusting the Pressure of the Pressure Roller
against the Capstan .................... 4
5. Tape Tension Control ......................... 4
5.1 Checking the Tape Tension Control ............ 4
5.2 Adjusting the Height of the Tape Tension Control ..... 4
6. Electrical Pause Control ........................ 5
6.1 Testing .......................... 5
6.2 Adjustment ........................ 5
7. Fast Forward and Rewind Operation ................. 5
8. Speed Selector ............................ 6
8,1 Testing .......................... 6
8.2 Adjusting the Friction Wheel ................ 6
83 Changing the Friction Wheel ............... 6
8.4 Equalization Selector ................... 6
9. Automatic Tape Stop .......................... 7
9.1 Testing .......................... 7
9.2 Adjusting ......................... 7
10- Tape Guides .............................. 7
11. Sound Heads ............................. 7-8
12. Lubrication and Servicing ....................... 8
12.1 Lubrication ........................ 8
12.2 Servicing ......................... 8

The proper performance of service operations on UHER tape recorders requires the
following items in addition to the usual workshop equipment:

vacuum tube voltmeter UHEFl alignment tape
audio-frequency oscillator UHER test tape

oscilloscope circlip pliers

wow and flutter meter Spring balance, range 1,0009
demagnetizer spring balance, range 50 g

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The brakes that act upon the clutch have different functions and should therefore be checked and 22Hi-FiSpecial
adjusted separately. 24Hi-Fi Special

3.1 Checking and Adjusting the Clutch Brakes (see Fig. 6)
The clutch brakes act upon the lower section of the clutches which form a single assembly along
with upper section and flat springs.

Left-hand brake: Press start and pause control keys: brake (A) should press against the lower clutch
section. Release pause control key: brake (A) should move away from the lower clutch section.
If necessary, the clearance can be adjusted by bending the lug (B).

A BL MK C

Right-hand brake: Press start key: brake (C) should move away from the lower clutch section Press
Stop key: brake (C) should press against the lower clutch section, The brake may be adjusted by
bending the lug (K). When the recorder is switched to FORWARD or FlEWlND operation. the left-hand
and right-hand brakes should move away from the lower clutch sections. They may be adjusted by
bending the lug (L) or (M). as the case may be,

3.2 Checking and Adjusting the Brakes of the Braking Discs (see Fig. 6)
The brakes at the braking discs affect the payout pull of the clutches and are controlled by way
of the FORWARD/REWIND switch.

Left-hand brake: Switch recorder to REWIND: brake (D) should move away from the braking disc (E) of
left-hand clutch. Switch recorder to STOP: brake (D) should block the braking disc (E) of the clutch.

Right-hand brake: Switch recorder to STOP: brake (F) should move away from the braking disc (G) of
the right-hand clutch. Switch recorder to REWIND brake (F) should block the braking disc (G) of the
clutch. The clearence can be adjusted after loosening the nut (H) or (I), as the case may be.

sums- ,

4. Tape Feed

4.1 Measuring the Feed Pull (see Fig. 7)

Before the next test. all the parts that serve for feed-
ing the tape should be cleaned with benzene. Place the
reel with a short tape on the turntable of the right-hand
clutch, thread the tape through the tape guides, and
suspend the spring balance in the free end of the tape
and hold in the hand. The spring balance must not be
pulled. Press start key and the spring balance will indi-
cate the feed pull. 1» Fig 7

Nominal value 400 gm t 50 gm 3

he?

A a: