7· 1 . INTRODUCTION
SECTION VII
BACKDATING
This manual section contains information on instruments which are older than the in
struments documented in other manual sections. These backdating changes are referenced
throughout the manual by a numbered delta (d#) . The number indicates the number of the
corresponding backdating change.
7 ·2 . .:l 1 -90MHz FILTER CIRCUIT
7·3. Applicable Serial Numbers
•
Information not available at this time.
7·4. Affected Manual Areas
•
Conversion Section Adjustments, Paragraph 5-43 tt/xx.
•
1 750A 00230 and below.
•
SO A2-Conversion Section, Schematic A-2.
•
Replaceable Parts, Table 6-3 .
7·5. Description of Change
Models with serial numbers listed above have no adjustments for the 2nd Mixer Board (A-4),
90MHz Filter Circuit . Schematic Drawing 7-1 and Replaceable Parts Table 7-1 show the cir
cuit and part differences respectively. Schematics and parts tables are located at the end of
this manual section.
7 ·6 . .:l2-IF FILTER CIRCUITS
7·7. Applicable Serial Numbers
•
and below.
7·8. Affected Manual Areas
•
IF Filter Adjustments, Paragraphs 5-29/5-40.
•
16 dB Amplifier Adjustments, Paragraph 5-41 .
•
SO A3-Final IF Section, Schematics A-3a/b/c.
•
Replaceable Parts , Table 6-3 .
7 ·9. Description of Change
Models with serial numbers listed above use an A- l I , A-12, and A- 1 3 Board as the IF circuit
instead of the A-17, A- 1 8, and A-1 9 Boards. The differences in these boards do not affect
the IF adjustment principles; however, some of the adjusting components have changed.
Scans by ARTEK MEDIA =>
7- 1