Harry,
Also make sure you watch out for the total amp draw. For example a lot of older packs had maybe 2 or so amps for a total of maybe 24 "volt amps" or watts for example (12 volts x 2 amps). If you've got 10 items each wanting 0.2 amps at 12 volts you should be OK. The amperage or wattage is sometimes listed on each device. If not available or you're not sure about it, just make sure the electrical connections/lines, etc don't get too hot.
Richard
Batteries used for things like this are almost always 1.5 volts DC. So, depending on how the batteries are arranged, the actual voltage applied will a some multiple of 1.5 - 3.0, 4.5, 6.0 and so on. So, the first thing to do is determine the total voltage going into the accessory. It's not a firm rule, but I'd say 99% of the time it will be the number of batteries x 1.5 volts.
If you have a variable DC power supply, all you need to do is set the dial so the right voltage comes out and you're all set. The best thing to do, of course, is use a meter, and if you don't have a meter, the best thing to do is go get one. You can get one at a place like Harbor Freight for under $10, and it will be of great help in many ways after this project is done.
What you don't want to do, though, is apply either AC voltage or the wrong DC voltage.
It takes an iron man to play with a toy iron horse.
I am new to Model Railroading and just know enough about electric to get in trouble. I have several Dept. 56 & Lemax accessories that are battery operated, I know I can buy power supplies and plug them in, I was wondering if I could instead run them off of my CW80 tranformer instead? How would it be done, would I clip the battery pack off and just wire direct or is there something else I need to do?
Thanks
Harry