Locomotive was working. I rebuilt the smoke unit. Now it does not move. It hums, light does not work, E unit clicks. Does it matter which spade connector is on which side. Wondering if I accidentally have connected to wrong sides of brushes.
There are several types of 302’s that were made. 302’s with diecast boiler shells use the 4 wire connection from the tender to the engine. It does not matter if the connectors are swapped on the brush tubes.
302’s with plastic boilers were made in 1952 and 1953 and use a 5 wire connection between the tender and boiler shell. While the brush tube connections can be swapped it is preferable to wire it per the factory wiring diagram.
Easy to follow color wiring diagrams for both engines are online at www.rfgco.com.
It is also worth asking, when you rebuilt the smoke unit, what way was it rebuilt? I learned that the 4 and 5 wire setups have different resistances for the smoke unit heater element- I believe 25 ohm for the 4 wire setup. 40 ohm for 5 wire locos.
It is possible to convert a 4 wire loco to 5 wire configuration or vice versa by re-wiring the model, and making sure the smoke unit has the right resistance for the setup.
-El
Thank you for the responses. Mine is the 1948, 4 wire, configuration. I pulled the engine from shell and wheels etc. move easily. So at this point start checking out the E unit. Although I did nothing to the tender other than disconnect it from the locomotive. Thanks again
I used a 27ohm resistor.
As you’ve noticed, I’m a newbie to this site and train repair. Tested the loco by itself. Forced me build a simple test stand. The loco runs good. Light is on, smokes, moves along smartly. So, off to the E unit. I’m sure you’ll hear from me again.
Appreciate the help.
Sounds like you isolated the problem. Gilbert reverse units are relatively easy to fix and parts are available.
If you purchase new fingers be aware that almost all the ones sold are too long, they must be bent back slightly to make proper contact with the copper sections on the drum. The only source I know of with the correct original fingers is www.ttender.com.
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How can I check the voltage coming out of the reverse unit’s jack plate pins?
The loco runs fine on test bench without tender. With tender, it ran for very very short time. Then a spark near the cow catcher and track and train essentially lost all power. I looked and nothing touching track except wheels and all wheels on track rails as they should be.
I would like to see what is coming from reverse unit to locomotive before I tear into reverse unit.
Thanks to all.
More clarification. I experienced this at two different places on track. Other trains run fine on track.
So don’t believe it’s a track issue.
Lets first address the spark near the front of the engine. That is most likely caused by a metal tire coming loose from the white plastic insulator. When it happens the result is sparking and a short. Check to see if all four metal tires are tight and fully outward on the white insulators. If not they are easy to repair. Push the loose tire back towards the chassis, put two drops of superglue on the white insulator surface, the pull the metal tire fully back on the insulator.