I'm in a weird situation. I'm trying to reverse engineer a circuit in order to duplicate it. It's all analog and wire wrapped, but I can't figure out what one of the chips is (qty 2), as far as a part number is concerned.
The parts (2) in question are transistor arrays, but 24 pin wide DIP packages.
I've built later versions of the same circuit, but in that instance, three ULN2004s were used instead of two of the larger chip.
Both the older circuit I am trying to replicate and the one I've already built are driving 6V incandescent lamps. If it matters, there are 22ohm 1/2W carbon composition resistors in the unknown circuit, one for each lamp, but I don't know if they are being used as a sink on the transistor, or for current limiting on the lamps themselves.
Any suggestions are welcome. Please remember that I realize I can make this circuit with modern components, but that's not what I am attempting to do.
The parts (2) in question are transistor arrays, but 24 pin wide DIP packages.
I've built later versions of the same circuit, but in that instance, three ULN2004s were used instead of two of the larger chip.
Both the older circuit I am trying to replicate and the one I've already built are driving 6V incandescent lamps. If it matters, there are 22ohm 1/2W carbon composition resistors in the unknown circuit, one for each lamp, but I don't know if they are being used as a sink on the transistor, or for current limiting on the lamps themselves.
Any suggestions are welcome. Please remember that I realize I can make this circuit with modern components, but that's not what I am attempting to do.