Diode Conversion For Lionel 1033

awesome tutorial!.....can you provide info on the diode itself? where to get it? what type it is?......thanks for the tips!

Just complete the same upgrade with a 16 amp stud diode.  Found after removing the old rectifier there was insufficient clearance for the stud and nut when attached to the original mounting plate.  My bracket was difficult to bend so I decided to mount the diode parallel to the mount plate using a 2" x 1/2" right angle from the hardware store.  Shortened the side attached to the mounting plate to 1" and the other side to about 3/4", short enough to clear the transformer cover.  Used a machine screw, washer and nut to attach the new bracket to the mounting place with a few drops of thread locker to keep the nut tight.   Hardest part was finding the correct size machine screw in my parts bin.  Replaced the missing resistor wire with a new 10 watt 1.8 ohm resistor.  

Also, the rivet holding the plate was loose so I drilled it out, threaded the bracket hole and secured with a machine screw and washer.  

With the plate removed from the transformer it was much easier to secure all the hardware. 

Unless I missed it, what the diode number?  Diodes depending on part number, are made with either anode or cathode side oriented towards stud side.  For old PW motor whistle, polarity unimportant, but modern locos with electronic whistle and bell, polarity matters.

The favorite recommendations are the 1N1190AR, 1N1186AR, or 1N1184AR diode available from many electronics suppliers. These will retain the stock polarity of the transformer. (Note that for some transformers, this is the reverse of the current conventions set forth post manufacturing - in that case you can opt to use the same numbers without the R to get a diode of the opposite polarity).

rrman posted:

Unless I missed it, what the diode number?  Diodes depending on part number, are made with either anode or cathode side oriented towards stud side.  For old PW motor whistle, polarity unimportant, but modern locos with electronic whistle and bell, polarity matters.

There is no # visible on the diode, purchased from a large Lionel online parts supplier "Justtrains.com" out of Sussex NJ.  They sold two diodes, standard and stud 16 amp (used mainly in the large 2 handle transformer).  This diodes markings indicated the stud is the anode (+) and the solder connection cathode (-).  Therefore is currently wired the reverse of factory.   This transformer was purchased in 1952 and is only used to run post war (1950's) trains.  It could easily be wired to factor spec but that did not seem to matter.  Somewhere along the line the resistor wire was clipped and replace with a piece of hookup wire.  Since they also sold the 1.8 ohm 10 watt resister went with than in place of the resistor wire.  The line cord was brittle so that was also replaced with the correct sized molded plug cord.

Any reason to reverse the polarity to match the factory diagram?

bmoran4 posted:

The favorite recommendations are the 1N1190AR, 1N1186AR, or 1N1184AR diode available from many electronics suppliers. These will retain the stock polarity of the transformer. (Note that for some transformers, this is the reverse of the current conventions set forth post manufacturing - in that case you can opt to use the same numbers without the R to get a diode of the opposite polarity).

There is no # visible on the diode, purchased from a large Lionel online parts supplier "Justtrains.com" out of Sussex NJ.  They sold two diodes, standard and stud 16 amp (used mainly in the large 2 handle transformer).  This diodes markings indicated the stud is the anode (+) and the solder connection cathode (-).  Therefore is currently wired the reverse of factory.   This transformer was purchased in 1952 and is only used to run post war (1950's) trains.  It could easily be wired to factor spec but that did not seem to matter.  Somewhere along the line the resistor wire was clipped and replace with a piece of hookup wire.  Since they also sold the 1.8 ohm 10 watt resister went with than in place of the resistor wire.  The line cord was brittle so that was also replaced with the correct sized molded plug cord.

Any reason to reverse the polarity to match the factory diagram?

@aka1178, the consequences of having reversed polarity of the diode means that the horn/whistle and bell controls will be reversed for newer locomotives. Your 1033's whistle control will activate the bell on such equipped locomotives (instead of the horn/whistle).

You are correct that the pre&postwar locomotives don't have a polarity sensitivity and will whistle/horn regardless of the polarization.

Thanks for the detailed explanation, since it's easy to change I most likely reverse the wiring so it matches the transformer factory wiring diagram.

Since you are using a stud diode, I'm not sure how easily one can "reverse the wiring"... usually one employs a diode of opposite polarity.

If  your 1033 isn't fully integrated and phased with a larger layout in common ground scheme, you can simply reverse your leads to the center and outside rails to effect reverse polarity without rewiring the transformer.

Move the connections (transformer/ resistor) soldered on the bracket to the lug on the diode and the connection from the transformer whistle lug from the diode lug to the bracket.  The bracket is attached to the top insulator plate and isolated from the rest of the transformer.

aka1178 posted:

Thanks for the detailed explanation, since it's easy to change I most likely reverse the wiring so it matches the transformer factory wiring diagram.

Don't do it.

The diagram is actually wrong. Always connect the cathode to the center rail track connection - in the case of the 1033, this would be the "U" terminal - to keep to the convention of the positive offset to the train for whistle, negative for the bell.

Found this service manual for the 1033 transformer, indicates that correctly installed the anode (stud in my case) should go to the whistle post, am I reading it wrong.  I actually still have the original "Instructions for Operating Lionel Multi-control Transformers".  This shows the U post being connected to the outside rail.  Attached both service and operating manual pages

This is where things get messy - The Lionel docs are NOT WRONG! The polarity indicated is as I find most stock transformers. They predate the DC offset polarity convention. It is common to use a stud diode to reverse the polarity of these to bring them into compliance with the DC offset polarity convention, but if the operator was content with he stock polarity and/or wired the transformer into their empire accounting for the stock polarity, why change it? Also, generally followed conventions have the center rail be the variable voltage, and on single throttle transformers such as the 1033, this is the U post.

Take a peek here for Lionel's transformer wiring matrix: http://pictures.olsenstoy.com/cd/transfmr/ps6.pdf

Only change the polarity if you have a reason to do so - if you are content with the operation currently, or can swap the inside and outside leads, I wouldn't necessarily recommend it.

So you don't recommend changing my upgrade connections to match the polarities shown in the service manual? 

Only using to sound the whistle on a 1952 engine 2025 tender (once that's fixed).  The relay needs replacement, some where along the line the relay was energized enough to partially melt the plastic whistle box.  Think the windings are shorted or they were cooked since the electro magnet barely works anymore.

Unless you have a stated need to change the polarity, run with what you have. Postwar locomotives don't care about polarity of the DC offset and will operate their Whistle/Horns with both a + or - offset.

aka1178 posted:

So you don't recommend changing my upgrade connections to match the polarities shown in the service manual?

That's right. You have it wired correctly if it's the opposite of the service diagram. If you are using "U" on the center rail, you can test this by running a newer loco with horn(or whistle) & bell. The 1033 will trigger the horn, not the bell.

Thanks

Thanks

Here is a picture of a diode installed on my 1033 transformer.

I removed the old whistle rectifier and parts, cut off the the old mounting bracket out of the transformer, and soldered in the diode.

Boy, do those whistles blow now and every time!

Quick and easy.