EIP 545A - Page 62

CONNECT A SPECTRUM
ANALYZER TO
A106J3. AS THE
COUNTER FINDS THE INCOMING
SIGNAL AN I.F. OF
125 MHz
f 20 MHz SHOULD BE
GENERATED-THEN THE I.F.
SHOULD BE CORRECTED TO
125 MHz EXACTLY.
FREQUENCY INPUT OUTSIDE
FREQUENCY
LIMITS OR SIGNAL
SELECTOR ON A106 BAD.
NO I.F.
-
I.F. MORE THAN 20 MHz FROM
125 MHz, OR CORRECTED TO
THE WRONG FREQUENCY.
.
VCO POWER AMP BAD.
DOES NOT
CORRECT I.F.
-
PERFORM CONVERTER
CALIBRATION
{SECTION 7). IF 1 yEsdl
PROBLEM IS NOT FIXED, PRESS:
VCO
0 LOCK CIRCUITRY
TEST.
0. 6. WITH A SENSITIVE
ON A108 BAD.
I.F. THRESHOLD BAD.
SCOPE .LOOK AT A100J7 PIN 2.
I CHECK THE RAMP FOR ANY 1 -
- . . - - . . . . . - . . . . . . . . . - . . . . . . .
I LARGE STEPS OR NON-
LINEARITY. IS THE RAMP O.K.?
I
Figure 6-17. Band 3, continued
N 0
r
A108 FREQUENCY CONTROL
DAC BAD.
Scans by ArtekMedia © 2007