Norlin Prodigy Modification

Page 2

SECTION 6
MODIFICATIONS

6.1 GENERAL INFORMATION

This section provides updating information on
the first 11,000 Prodigys produced and also presents
various ways to modify the synthesizer for inter-
facing. Instruments below serial number 4160 are
very difficult to modify and require skillful and
delicate use of a soldering iron as described below.
Instruments above serial number 4160 are easier to
modify and have a newer printed circuit board which
accommodates the appropriate interfacing pads. In
addition, the modifications described Drovide addi-
tional interfacing ideas for use with sequencers and
other accessory devices not found in standard produco
tion Prodigys.

6.1.1 SOLDERING TECHNIQUES

CAUTION

A low wattage soldering iron of less than
40 watts, such as Radio Shack 64-206,
MUST be used to avoid damage to printed
circuit board traces. The excessive heat
of higher power irons or soldering guns"
destroys boards by lifting the fragile copper
traces.

To solder a lead to a trace, scrape approximately
1/4 inch of insulation from the trace with a knife and
tin the trace and component lead(s) BEFORE attach-
ing them. After tinning, hold the component lead
against the trace and heat both until the iron just re-
flows" the solder. Failure to do this may result in
severe trace damage. Use only a high grade ROSIN
CORE solder such as Radio Shack 64-002 but not
any type of ACID CORE solder.

When it is necessary to cut a trace, use a sharp
knife to remove approximately 1/16 inch of the trace,
so that solder bridges do not result.

When unsoldering components, use a desoldering
tool such as Radio Shack 62-2085.

22

If IC sockets are added or replaced, use a high
quality nylon type such as those made by AMP. The
use of Molex sockets is not recommended. The high
impedance circuits of synthesizers require the best
possible insulation resistance and very low contact
resistance.

Resistors added to the component side of the
board must be glued to the board with a silicon
adhesive to eliminate any possible movement.

CAUTION

After necesary soldering is completed,
ALL FLUX MUST BE REMOVED from
the board with a flux remover such as
Radio Shack 64-2324. If the flux deposits
are not removed, pitch instability problems
may result.

8.1.2 COMPONENT GUIDELINES

Components required for modification are as
follows:

a. All resistors are 5%, 1/4 watt unless otherwise
noted.

b. All resistors specified as 1% are RN55D type
1%, 1/4 or 1/8 watt, metal film resistors.

c. All signal diodes are 1N41485.

d. All wire is 24 gauge, stranded.

For connector repair and replacement, refer to
the following paragraphs and illustrations.

The connectors are the OLE. (Commercial Inter-
connection System) crimp socket type made by AMP
which have 0.1 inch (2.5mm) mounting centers. This
is a reliable connection system which can easily be
replaced if necessary. The portion of the connector
attached to the printed circuit board (header) is re-
placed by simply solderinga new one in place. Headers
of 5, 6 or more pins can easily be cut using wire
cutters to replace 1, 2, 3 or 4 pin versions. Simply