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Discussion Starter · #1 ·
I have an old 1033 that, when the whistle switch is turned, causes the train to pick up speed instead of blow the whistle. In a few other threads on this and ctt site it was advised to swap out the old rectifier with a 5 amp diode. So, I went to RadioShack and bought a 6 amp rectifier diode (all they had). I replaced the rectifier with the diode but still no whistle and the train picks up speed.

Did I replace the diode incorrectly or is there another problem?

For whatever reason I'm unable to get the images showing from flicker so here are the links


Old rectifier

http://www.flickr.com/photos/[email protected]/7680170090/
Close up of rectifier



New diode
http://www.flickr.com/photos/[email protected]/7680170622/
 

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Remember +dc is for whistle -dc for horn if am I not wrong.
so try the other side of the diode.
Andre.
relay in tender. the coil responds to dc component on the ac line. the coil could be open. it is normal to see a slight increase in speed when the diode(s) are shorted out by pushing the horn/whistle button. normally its two diode junctions (total of 1.4 volts) that will pick up the relay coil.
 

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I cannot tell from your pictures how you have the diode wired up. The original rectifier was between the brass tab with the hole in it that you can see through the hole of the metal plate that the rectifier was mounted on. The new diode should be wired between the metal plate and the brass tab.

Start by putting the red and white wires back where they were. There is no need to move them.

If you get the diode in backwards, a whistle in a post war tender will still work OK. It is not polarity sensitive.

If the diode is in backwards, and you use a newer tender with a whistle and bell, the bell will operate and the whistle will not.
 

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SeaB,

Can you sketch out a wiring diagram of how you've wired the diode? It's hard to tell via your photo, per other comments, above.

TJ
 

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I look at a diagram first. Olsen The first page shows a diode with three connections . You made two, The third is that brass fitting supporting the disc. To the right in the second photo.I think it gos to coil point 5. See page two to compare. It may be backwards.

Check where the connection should be in theory then figure how to hook it up.

I never got around to doing one. Is 5 amps enough?
 

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5 amps should be enough. Remember, for half of the sine wave the diode is turned off, so if the loco draws 10 amps, the diode can carry the current. Now at 5 amps, the diode is dissipating about 3 watts which is quite a bit unless it is on a heat sink. However, most locos don't draw 5 amps, and when the whistle controller is in the second position, there is a low ohm resister (a piece of resistance wire) across the diode which greatly reduces the current through the diode.
 

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Discussion Starter · #9 · (Edited)
SeaB,

Can you sketch out a wiring diagram of how you've wired the diode? It's hard to tell via your photo, per other comments, above.

TJ
ALCON,
Thanks for the replies so far.

Based on this diagram PDF from Olsen's, I removed the rectifier leaving only the bar that held it. Then I took wire 6 and 7 (in the diagram) off that bar and soldered both wires, 6&7, to one end of the diode and soldered the other end of the diode to the lead that the bar is connected to.

http://pictures.olsenstoy.com/cd/transfmr/ps1032c.pdf

My 1033 7 wire was attached in the manner addressed in the NOTE at the bottom right of the PDF.

Does that help?
 

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In looking at the first-page wiring diagram in the link that T-Man gave, I think that 6 and 7 are wired to the cathode side of the diode (the banded side).

However, in your new-wired pic (from post 1), it looks like you've wired 6 & 7 to the anode side of the diode.

I'm no elec expert, though ...

TJ
 

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Discussion Starter · #11 ·
In looking at the first-page wiring diagram in the link that T-Man gave, I think that 6 and 7 are wired to the cathode side of the diode (the banded side).

However, in your new-wired pic (from post 1), it looks like you've wired 6 & 7 to the anode side of the diode.

I'm no elec expert, though ...

TJ
So you're saying the diode is backwards? But Servoguy said the direction doesn't matter. I'll give it a try though when I get back from New Hampshire Monday.

Go Gabby! USA USA USA
 

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For a post war whistle tender with a whistle relay or for a diesel loco with a horn relay, the polarity of the diode doesn't make any difference. The relay is not polarity sensitive.
 

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Discussion Starter · #14 ·
Well, I don't have any with a bell. I'll reverse the diode and see what happens. Whats the worst that could happen? Best case scenario, it works; worst case... myabe I invented a time machine...:sly: Mr. Wizard!!!! Noooooo!
 

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Discussion Starter · #17 ·
There's a resistor in line with one of those wires, right? Are you sure the resistor is still working OK?
Okay, I'm back to working on this transformer. To pick up where I left off, I had just replaced the rectifier with a 6a diode but was still having the same problem of speed increasing vice the whistle sounding when I tried to make the whistle start.

Link to diagram: http://pictures.olsenstoy.com/cd/transfmr/ps1032a.pdf

TJ had asked if I still had a resistor in line as per the diagrams on page one of the link above. The resistor is actually the wire itself, #1033-103. this is wire number 7.

Question,
I tested the resistance of the The wire, 1033-103, and there was no resistance. My ohm meter maxed out (it's auto set at rx 1k ohms). Could this assembly be the problem? If so, what type of resistor would I replace it with?
 

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The resistance wire is a very low resistance. Your meter will not measure it. You would need a micro ohmmeter with a Kelvin connection to measure the resistance. It is also in parallel with the diode and reduces the current through the diode when the whistle control is in the 2nd position (where the train speeds up).

Does the diode smoke when the tender is not on the track and you operate the whistle control? I had a problem some time ago where the pickup rollers on a tender would spark when I operated the whistle control. Some wire inside the tender had moved somehow and was shorting to the frame of the tender. This wire was not hot unless I tried to blow the whistle.
 

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Discussion Starter · #19 ·
Nope. No smoke, no smell. Everything works great, just the whistle. I guess maybe I have the wrong rectifier type diode. It was the only thing that said rectifier at radio shack.
 

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Okay, I'm back to working on this transformer. To pick up where I left off, I had just replaced the rectifier with a 6a diode but was still having the same problem of speed increasing vice the whistle sounding when I tried to make the whistle start.
It's normal for the engine to speed up if it's not the original PW tender with the AC motor. The voltage is boosted when you blow the horn to compensate for the current draw of the tender, which was basically like adding an engine on the tracks.

The wire resistor you mention is a 1.8 ohm resistor, so a standard hand-held meter won't measure it as Bruce states. I measured two of them on my bench meter, a new one was 1.8, and the old one taken out of a 1033 was 1.9.

If you're reading infinity on this part, that's saying it's defective. A 2 ohm 10W resistor is a valid replacement. Here's a 2 ohm 10W Resistor that would do just fine. If you really want to be exact, here's a 1.8 ohm 10W resistor for the same price.
 
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