TM 11-6625-2965-14&P
APPENDIX
D
MANUAL BACKDATING CHANGES
Manual backdating changes describe changes necessary to adapt this manual to earlier instruments. TO
adapt the manual to serial numbers prior to 7L2301 inspect the following table for your serial number and
then make the appropriate changes.
For serial numbers 7L4450 and up check for inclusion of change sheet.
CHANGE 1:
In the replaceable parts table, make the following
changes:
Delete Q10.
Delete R51.
Change R53 to fxd, comp 10 ±5% ½W, EB-1005,
01121, part No. 0686-1005.
Change R54 to fxd, ww 5.25 ±0.5% ½W, Type
E-30, 01686, Part No, 0811-1921.
Change R81 to var. ww 100 , Type 110-F4,
11236, Part No. 2100-0281.
On the schematic remove transistor Q10 in current
limit circuit and connect circuit as shown in
Figure B-1.
The circuit description Paragraph 4-19 should now
read as follows:
4-19 Current limiting occurs when diode CR16
becomes forward biased.
Its anode potential
is
determined by the voltage at the base of Q4.
The cathode potential of CR16 is determined by
the voltage drop acress resistors R53 and R81
Figure B-1.
which, in turn, are connected across the cur-
rent sampling resistor(s). The cathode poten-
tial of CR16 is a function of the output current.
A
S this current increases, the drop across the
sampling network increases, and CR16 will
start to conduct.
Conduction of this diode
clamps the base of Q4 to a potential which de-
creases the conduction of the series regulator,
thus limiting the output current,
Potentiometer
R81 permits the cathode potential of CR16 to be
varied and thus charges the current limiting
threshold.
Paragraph 5-52, Step (e) should read:
“Adjust R81 until differential voltmeter indicates
2.55 Vdc . . . .”
D-1
