Technical data
    Chapter 8: Troubleshooting  
Series SPB Audio Boosters Manual, Revision A 
8-7
8.2.6 Procedure F 
If the green AC LED is “ON,” the yellow TROUBLE LED is “ON,” D78 EXP SHORT LED is 
“ON,” the supervision circuit is unable to read the 1/2W EOLR. This can be caused by: 
Expansion circuit is shortened. 
Perform the following: 
Check the wiring to EXP OUT and ensure there is no short. 
8.2.7 Procedure G 
If the green AC LED is “ON,” the yellow TROUBLE LED is “ON,” and D87 EXP OPEN LED is 
“ON,” the supervision circuit is unable to read the 1/2W EOLR: This can be caused by: 
Missing or Improper 1/2W EOLR.   
Open or loose wiring on the EXP OUT terminals. 
Open EXP OUT appliance circuit. 
Perform the following: 
1.  Check that 1/2W EOLR is in place and is UL Listed 10K Ohm, 1/2W resistor. 
2.  Check the wiring to EXP OUT terminals and ensure there is no open circuit. 
3.  Troubleshoot the expansion circuit for incorrect wiring. 
8.2.8 Procedure H 
If the green AC LED is “ON,” the yellow TROUBLE LED is “ON,” and D100, GF LED is 
“ON,” a ground fault condition exists on the output wiring. A GF trouble condition might be 
caused by: 
Appliance wiring touching conduit. 
Improper Installation of an appliance(s). 
Perform the following: 
1.  Disconnect appliances from the strobe and speaker connection on the motherboard. 
2.  Troubleshoot NAC circuits by checking for a resistance reading other than infinity 
between the appliance leads and the conduit. 
8.2.9 Procedure I 
If the green AC LED is “ON,” the yellow TROUBLE LED is “ON,” and D25 AUD1 SHORT 
LED is “ON,” the supervision circuit is unable to read the 1/2W EOLR: This can be caused by: 
Audio appliance connected is shorted. 
Shorted connection on the AUD1 OUT circuit. 
Circuit installed improperly. 
Perform the following: 










