8 9710 VCA
000216
Transistors
Install the transistors by inserting their three leads
through the holes provided for them in the circuit board.
Note that the transistors are polarized by the flat side
of the case. When the transistors are properly
installed this flat will align with the corresponding mark
on the circuit board legending.
Notice that two different types of transistors (2N3904 and 2N3906)
are used. The type will be written on the body of the part.
Two of the transistors have been specially selected to have
matching characteristics and will be packed together.
Keeping this pair together is important for optimum circuit
performance. Since they are matched, it makes no difference
which transistor is used for which designation.
DESIGNATION
TYPE
( ) Q3/Q4
2N3904 NPN Si Transistor Matched Pair
One transistor has been selected for use as a noise
source and has one of its leads cut short.
( ) Q5
2N3906 Selected for noise.
Install the remaining transistors as follows:
listed below:
2N3906 PNP Silicon Transistor
( ) Q1
( ) Q2
( ) Q6
( ) Q7
( ) Q13
listed below:
2N3904 NPN Silicon Transistor
( ) Q8
( ) Q9
( ) Q10
( ) Q11
( ) Q12
( ) Q14
( ) Q15
Trimmer Potentiometers
The two trimmer potentiometers surface mount to the
board rather than having their leads pass through it.
First "tin" the trimmer mounting pads on the circuit boar
by melting a little solder onto them. Solder the trimmer
to the board by holding the pins against the tinned pads
and remelting the solder.
The straight line of the pc
graphic symbol corresponds
to the flat face of the
transistor case.
Note flat
Q5 has one lead removed
Trimmer potentiometers surface
mount by tinning the mounting
pads and remelting the solder to
the component pins
Note cut-off
lead
