Continuing to test my loop I ran my 2025, when I hit the whistle button it stalls out as the whistle sounds. It's about a 10x12 loop using a postwar ZW. Any thoughts would be greatly appreciated as I will now go pout in defeat yet again. Thanks again for any thoughts.
Sounds like the current draw of the whistle is overloading something. Hard to imagine the ZW being overloaded, does the headlight go dim or out when you hit the whistle? Did you try the other handle on the ZW?
Thanks sir, I checked the other side and it seems good. Now I have a problem with the right side of the ZW?
The ZW has a circuit to increase the voltage to the track when the whistle is activated to compensate for the current draw of the whistle motor. That is why many engines actually speed up when the whistle is activated. It sounds like that circuit may not be working on one side of your ZW.
Earl
I'm guessing the whistle switch in the ZW is not making contact on the second side, or the resistor has gone bad. Would a ZW Maintenance Manual help you check it out?
Have you lubed both bearing of the whistle motor? If not, the whistle motor will draw excess current and slow down the loco. Also, is the loco pulling any cars? More cars will increase the voltage from the transformer and make the whistle work better.
There are two positions for the whistle controller. The first position provides a DC offset to pull in the whistle relay. The second position raises the AC voltage and reduces the DC voltage to keep the engine from slowing down. If your whistle control doesn't act like this, it may have something wrong with it. You have two whistle controls on the ZW. Try both of them to see if the work the same.
BB
Yes the left side is fine. What are some ways to test and zero in on the problem, what to look for exactly? It completely brings the loco to a stop while the whistle blows.
You are going to need a drawing of the circuit for the ZW and probably a meter. Best price for a meter is Harbor Freight. The whistle switch could be bad, or the resistor (looks like a piece of wire) that is across the copper oxide rectifier with the switch in the 2nd position could be bad or disconnected.
The symptoms sound like the resistor to me. The rectifier gives him the shot of DC, but he doesn't get the voltage boost. It could be the second contact as well.
It sounds like the reversing/whistle switch is not making contact to bring in the compensating winding. You will need to pull the switch out and clean and check the contacts.
Larry
I pulled the cover off, are you referring to the two contacts the whistle switch go over when you push it forward? They are making contact, all the wires seem soldered. Next step, clean the two contacts I mentioned?
Yes, clean the contacts and give a little rub on them with some fine emery cloth. If that still does not work, possibly the resistor may be bad. Find the resistor from the other side, and swap it out as a test.
Bare with me a second. I see the two screws to pull the whistle assembly but how do you get the pin (switch rivet?) out to get the spring off so i can get to the contacts?
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