Version: 13. Sepe,mer 2004
12
Measure at test point, 47 = 10V +/- 5%
Measure at test point U2 = 6V +/- 5% (Track from c129 field B1 to the
left)
Measure at test point U3 = 5V +/- 5% Track from C21 field A6/7 up
When the measurements are OK, remove the power supply and the shorts,
and turn to the next section.
Section 2 T/R Switching
We begin with the trimming potentiometer P12, as mounting this is easier,
when no other parts ar present. PT6 lying means a 6 mm diameter compo-
nent. The value is printed sideways on the casing, and often difficult to
read. The mounting position is given by the three leads, placed in an equi-
lateral triangle.
[ ]P12 100K PT6 lying A/B5
Now the capacitors. After the electrolytic capacitors comes for the first
time a multilayer capacitor. It has a marking of 104, meaning 100 nF.
As examples of this type of marking, we present a few values:
101 100 pF 0,1nF 0,0001uF
102 1000 pF 1,0nF 0,001uF
103 10000 pF 10nF 0,01uF
104 100000pF 100nF 0,1uF
221 220pF 0,22nF 0,00022uF
222 2200pF 2,2nF 0,0022uF
223 22000pF 22nF 0,022uF
224 220000Pf 220nF 0,22uF
Note that the last figure marks the number of zeros. This type of capacitor,
type X7R, is often used to bypass RF. There Q isn’t very his, making them
unusable for resonant circuits. You will find more on capacitors in the FI
Workbench Book.
[ ]C126 100nF 104 A6
Now follows a film capacitor. WIMA film capacitors are nonpolarized, ma-
king the mounting direction unimportant. Good practice though is to
mount them, so the marking can be read. They are used at AF because of
their high Q. RM5 means raster measure 5 mm, most parts of the kit has a
raster measure of RM2,5 equalling 2,5 mm.
[ ]C127 0,22µF Film RM 5mm B5/6
Now follows a new component, the tantalum capacitor. These are
polarized as electrolytic capacitors. You will usually find their value
as text on the drop shaped body, and a small plus sign at one lead.
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