1033 Transformer... again

Again I yield to your expertise gentlemen, remembering that I am trying to clean up\ fix up this old train\transformer for a friend. I am very handy with rebuilding model airplane engines, and I have built a couple of bowser HO models with valve gear and all, but I have little knowledge of lionel, old whistle transformers, etc except for the 10-20 hours I have spent reading on the internet and tinkering. So.....

If I understand correctly, lionel usually has the ground on the outside rails and power to the center rail as far as the DC component for the whistle and the 1033 is usually wired such that the U terminal goes to the center rail. This would tell me that the positive side of the DC should go to the U terminal right? So, if I look at the schematic for the 1033 in the Lionel service manual it shows the rectifier facing such that the U terminal would have the negative side of the DC. So which is it? Should the cathode on the diode I am installing go toward the copper contact or toward the metal plate contact (where the red lead and the nichrome resistor wire meet)? I chose a 50V 6A diode. Does that sound sufficient? The biggest that Radio Shack sells these days. Sorry for all of the questions, I would just like to get this done and done right so my friend is still my friend in the end. Thank you again.

Steve

Reply to
seware
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Correct, an anomaly unique to this series of transformers.

Not necessarily. Postwar horn & whistle relays didn't care if it was + or - DC imposed on the track.

The way the schematic shows is correct. To check, try a modern loco or tender, w/ U wired to center rail. If the whistle/horn blows, it's right. If the bell sounds, it's wrong.

Plenty. Much of the current is shunted around the rectifier anyway after the "pick-up" phase of the activation is swept-through with the control lever.

Rob

Reply to
trainfan1

Which brings up another question. The nichrome shunt wire is not in that great of shape. Should it be replaced with a modern 1.5ohm resistor? My reading of the service manual indicates that this may have been mainly to save stress on the rectifier disk, that is, not holding the full voltage once the whistle tender relay initially opens. So, is it really necessary when using a modern diode? I would think that the diode would survive just fine if the whistle tender can sustain the full voltage. Just a thought. I better stop thinking or I'll have spent a lot of time putting new parts in an old tender. Thanks.

Reply to
seware

Oops. Old transformer that is. Must go to bed.

Reply to
seware

Leave it alone. Your E-units will be quieter with the shunt retained.

Rob

Reply to
trainfan1

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