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2024-08-24: I'm going to be a little light on details on this one, but wanted to drop this here for others... Rush job repairing a couple DUAL-LITE DL-7-12V Emergency Lights... There was a bit more work involved here than expected, even if the fixes were fairly easy once identified. Hopefully this will help someone else.
This is one of the units found that required work. The others were in similar shape, just with newer batteries.
Label found on one of the units... Unfortunately, even with this information, I can find next to no information on these. Everyone wants to sell me batteries for them, but that is only half the problem.
Best image I have of the circuit board... I wasn't taking a lot of images while working on these. Black wires are charge lamp. White wires are normally closed test switch. Blue wire is positive 12VDC output. Red is positive side of battery. Yellow is 0VDC output / negative side of battery. Transformer inputs are White - Common, Black - 120VAC, Red - 277VAC.
Electrical schematic of the circuit boards. Clicking on this image will give you a PDF schematic.
Problems Found:
All had exploded/leaky batteries.
One board with short due to corrosion from battery acid.
One board with broken black input wire on transformer.
last board low resistance 33K ohm resistor and one PN2222A transistor shorted.