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AS42L COMPACT DIMMER 
 Revision 2.2 OWNER’S MANUAL 06/01/2022 
www.lightronics.com 
Lightronics Inc. 509 Central Drive, Virginia Beach, VA 23454 Tel: 757 486 3588 
 
DESCRIPTION 
 
The AS42L is a compact four channel light dimmer. 
It has a maximum capacity of 1200 Watts per 
channel and a maximum total load capacity of 4800 
Watts. It is supplied with two input power cord stubs 
which may be connected to two different 120 VAC 
power services. The AS42L is intended for INDOOR 
USE ONLY. The unit operates using the Lightronics 
LMX-128 multiplex protocol. The AS42L may be 
operated in a relay (non-dim) mode. The unit will 
also function as a chaser and has several preset 
chase patterns which may be used. 
 
AS42L END VIEW 
 
 
 
 
 
 
 
 
 
 
 
INSTALLATION 
 
LOCATION: Locate the unit vertically with control 
signal connectors on the bottom in a well ventilated 
area away from moisture and heat. Two ½” holes 
are provided on the dimmer top cover to install a 
lighting bar pipe clamp and suitable safety cables. 
 
POWER CONNECTIONS: Extending from the 
chassis are two 20 amp line cords for connection to 
two separate 120 VAC, 20 Amp grounded services. 
Total capacity of the AS42L is 4800 Watts. 
 
LOAD CONNECTIONS: There are four numbered 
duplex outlets on the top of the unit. Each provides 
two connections for each of the output channels. 
You can connect up to 1200 Watts of lighting to 
each channel. 
 
CONTROL SIGNAL CONNECTIONS: 
 
The male three pin XLR connector on the unit end 
panel connects to the control console. The female 
connector is for connection to additional dimmers. 
The AS42L dimmer is compatible with the 
Lightronics LMX-128 and NSI/Sunn three wire 
 
multiplexed protocol. If you have older Lightronics 
dimmers which run in the obsolete Lightronics mode 
only, contact Lightronics for information on changing 
the mode. When using multiple dimmers, ALL 
dimmers MUST be in the SAME mode. 
 
CONTROL SIGNAL WIRING: 
 
2 
Console Power 
(+15Volts DC) 
Applies to input and output connector 
 
OPERATION 
 
NORMAL MODE (Non-Chaser): 
 
A green LED in the end panel will indicate that a 
valid LMX-128 control signal is applied to the unit. A 
DIP switch block on the end panel selects the 
starting channel number of the dimmer. The seven 
right hand switches control this function. For 
example, if all switch positions are down - the 
dimmer will respond to channels 1-4. Raising the 
switch on the far right will set the dimmer to respond 
to channels 5-8. A complete table of channel 
assignments is provided in this manual. You can 
address up to 512 channels with multiplex control. 
 
RELAY MODE 
 
Pairs of channels (1/2 and/or 3/4) may be switched 
into the relay mode. In this mode the output of these 
channels will be either off or full on depending on the 
control console channel setting. The trip point for 
turn on is aprox. 50%. The two left hand switches on 
the DIP switch block control relay mode channel 
selection. The UP position of the switches invokes 
RELAY MODE. 
 
CHASER MODE: 
 
When operating in the chaser mode the AS42L 
becomes independent of the control console and 
other dimmers. The green LED indicator is OUT 
when in the chaser mode. Chaser mode is turned 
on and off by one of the DIP switches on the end of 
the unit. A diagram on the unit cover shows the 
switch settings for controlling chaser operation. 
 
Eight different chase patterns are available. A 
"bounce" condition may be imposed on several of 
the chase patterns by setting one of the DIP