Resistor Notes; Install The Diode; Install U2, The To-92 Package 17.5 Volt Regulator; Figure 3-17.5 Volt Regulator Comes In To-92 Package - DYNACO SCA-80 Assembly Manual

Resistor Notes

 All the resistors are ¼ W, 1%, Metal Film
 K stands for 1000. Thus, 60K4 is a short-hand that means 60,400 Ohms. Some
people like to convert the K notation to a number by:
1. Replace the K by a decimal point.
2. Multiply the resulting number by 1000.
 Resistor orientation does not matter.
 Feel free to use a DMM (digital multi-meter) to confirm the resistor values before
installation.

Install the Diode

Be careful! Diodes have a polarity. Make sure the band on the diode aligns with
the banded end of the silk screen!
Designation Value
D1 1N4004
Here's what the 1N4004 diodes look like (not to scale). The package type is known as a
DO-41. The body is black, with a white stripe:

Install U2, the TO-92 Package 17.5 Volt Regulator

Although the package looks the same as typical transistors, the three integrated circuit
installed in this step is actually a voltage regulator. You may have to spread the outside
leads a bit to make it easier to insert it into the board.

Figure 3-17.5 volt regulator comes in TO-92 package

Orient the regulator so its body shape matches the silk-screen outline. Leave the top of
the regulator about ½" off the board! The lead length prevents stress on the body and
keeps the regulator safe from too much heat during the soldering operation.
Designation Type
U2 TL431
Don't use too much solder on the integrated circuit leads. This is one place where the
spacing is close enough that extra solder might cause short circuit between two leads on
the regulator.
Marking, type
4004, 400 PIV 1 Amp
Description
2.5 V adjustable shunt regulator
Page 7 of 15
Done()
Done? ()