Akai 1800 L Service Manual

Page 1

SEBVIBE
t MANUAL

1, 1th mama

E *mflBOOL

Page 5

CROSSTALK (Crosstalk between the tracks)

(TAPE)

Tape direction

As shown in the figure. first record a LOOO Hz sure mum
on track No. 3 It +3 VU level Next. remove the
LO) H1 input signal and record under a ruin-Input
condition.

Then. playback the up: on track NIL J and No. I
(reversed wnditton of upcl through the LOGO HI B.l [-
tBand Pas Filtcr Sensitivity , , . |:|)and ohtatn a tuna
between the two from the following fnrmuta.

Err
E: El

( =20 log (db)
C =Deslred crosstalk ratru (dbl
En=l .000 Hz signal output level
b1: l .0) Hz crosstalk output level "I 3
Er =No«tnput stgnal record level

FREQUENCY RESPONSE

Andre 1800!.

Frequency =-=Line Input -\.T.V.M

Oscillator Line (lutput

Connect tlte measuring instrument as m the above
diagram. and measure the frequency response tn the
following sequence :

RECORD :

I) Give a sine wave at Low Hz to the Line Input of
the recorder to be tested. thrntrgh an attenuator
from an audio frequency genflalnt

2) Set the Record/Playback Knob rrt "Rec" posrttott
and adjust the line input volume so that the VU
meter needle indicates "0" VU.

it Under the eondttttm described In (2). lower the
Input level l0 dh by means of the attcrtuatort

4t Record the spur frequency In IlIL' range nt' 50 HI In
H.000 HI from the audio frequency generator.

ILAYBACK

5) Set the Record/Playback Knob tn "Play" pUSlltUlL

"l Connect a V.T.V.M. to the Line uutpuL

7) Flu) hack the tape prcvtously recorded.

M Adjust the output level to "0" dbm at Low Ht as
rndteutcd on the V T.V.M. hy the range selectut ol~ :t
V IXVM.

9t Phi) hack tlte recorded spot trequettcres wrth the
conditions "119) make a menu) lulllpul level and
plot the value on :t graph.