Akai UCF 5 Service Manual

Page 2

STEREO CASSETTE DECK

MODELUC'F5

ALSO APPLICABLE TO BLACK PANEL MODEL

SECTION 1 SERVICE MANUAL ................... 3
SECTION 2 PARTS LIST ......................... 43
SECTION 3 SCHEMATIC DIAGRAM ................ 61

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2. DIGITAL COUNTER CIRCUITRY

OPERATION
2-1. Circuit Structure of 1C1 TC5054P oscillation circuit and a driver/decoder driving
TC5054P is an IC for a 4 digit, decade up/down the LEDs directly. The clock input is separate for
counter with a built-in 7 segment driver/decoder. down and up clocks and each input has a schmitt
On the inside, with the counter as base it is con- trigger for shaping the waveform.

structed of a 4 digit latch, multiplexer, scanning

1) Block Diagram

DIGIT SELECT SEGMENT DRIVE
T-RESET BLC a h c a
I 3

BCD-YO-I SEGMENT
SCAN IN DEDODER

R :xr

MULTIPLEXER

raAussER
I
l

TEST @- ' - -

l
5
mam

UP CLOCK

Down CLOCK

BORROW

MASTER
RESET

I
I
I
I
I. ___________________________________________________________________________________________ r

Fig. 5 TC5054P

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NOTES: 1. The Output Level Control should be at maximum.
2. Because each of these adjustments is vital to perfect Dolby NR circuit operation, ensure that they are
carried out with as few errors as possible.

. Except for Step 5 thru 7, 9 and 10, set Tape Selector to LN Position.
. Except for Step 12, set Dolby NR switch to OFF Position.
. Use the following cassette measuring tapes:

LN tape : TDK D 060 ,

LH tape : Maxell UD C~60

CrOz tape : TDK SA C-60

Metal tape : TDK MA-C C-60
. If it does not comply with the specifications, repeat Steps 4 to 8 and readjust.
. Adjust the oscfllators frequency to give a frequency counter reading of 19.00 kHz.
. Unless the core is moved unintentionally this adjustment is not necessary.

III-AL»

wflON

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-MEMO-

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