Leprecon LP-900 - Manual (Page 7)

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Leprecon/CAE, Inc. P.O. Box 430 Hamburg, Michigan 48139 810-231-9373
Leprecon®
Pro Lighting Equipment
REPAIRS AND MAINTENANCE
The most common repairs in Leprecon consoles will be replacing parts that are
physically damaged. Failure of opamps and LEDs is rare, and easy to diagnose
and repair.
The principal parts of a board subject to serious wear are the slide pots. They
are vulnerable to dirt and other contamination. The grease in a slider that gives it
a nice feel also traps dirt and dust. Unfortunately, there is no real way to remove
the dirt and leave the grease. Cleaning sprays remove dirt but also remove the
damping grease and will make the pots feel rough. Sliders should be spray
cleaned only as a last resort. Never use tuner or contact cleaners, which contain
abrasives on potentiometers! These are suitable for switches only. “BLUE
STUFF” contains abrasive – it’s good for switches and connectors – but do NOT
use it on potentiometers! “JIFI” (from Workman) and “WISSH” (from G.C.) are
good potentiometer and contact cleaners.
Leprecon consoles have a layer of fabric between the front panel and the slide
pots to keep dirt from falling into the pots. Keeping the board clean is the only
solution to prevent wear to the sliders. Ideally, the board should be kept covered
when not in use. Vacuuming the console out occasionally helps too.
Dust and dirt will make the sliders feel gritty and wear more quickly. Spilled soft
drinks leave a sticky caramel lacquer on matrix contacts and sliders. The main
attention a control board needs is keeping contamination out of the electro-
mechanical parts.
PLEASE consult with us before cleaning or lubricating the sliders.
Output circuits are not delicate, and can usually stand short circuits on outputs or
even ribbon cables plugged in backwards without damage. Power supply
regulators have current limiting and thermal shut-off, and will usually survive
shorts without damage.
Simple isolated problems, such as a single dead control channel or a short
between two channels, can usually be traced down quickly. Schematics include
opamp pin numbers. DC voltage test will quickly show what’s going on without
removing PC boards.
The most serious problems in a console are those that affect many circuits, such
as defects in the power supply, grand master and scene master or submaster.
Problems in these circuit boards will affect more than one module and must be
isolated to the single defective board.