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I have a Lionel 28613 Docksider on my bench. It will only run backwards.
I removed the shell, and found when it does run backwards two of the four large semiconductors (I am guessing they are SCR's) on the main board get extremely hot very quickly.

I disconnected the motor, and applied DC power directly to it, running the current through a Simpson 260 VOM to get an amperage reading.

With no load, and the voltage set to about 6 volts, the motor is drawing about two amps! (Could I have the meter hooked up wrong?) (Checked the meter manual, it was hooked up correctly)

I do not see or feel any binding in the mechanism.

 

Here is my guess:

The motor should not be drawing that kind of amperage, and needs replacing.

The forward semiconductors (SCR's?) burnt out due to high amperage.

 

I do not work on can motor / electronic control stuff very much.

What do folks think?

Last edited by C W Burfle
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Well,it certainly looks like you've got a duff motor.  Hard to say about the reverse board Power Transistors.  Do you have another motor (does not have to be identical), that you can hook up and see if forward and reverse are still functioning.  If not, you may have blown 1 or maybe both of the PT's controlling reverse.  These are very cheap from mouser, or digikey.  It might be worth getting a reverse board from Lionel at the same time as ordering a motor...looks like Lionel has both in stock

r0d

According to the Lionel web site, there are two versions of the chassis and motor on the 28613. Lionel differentiates them by the spacing of the motor mounting screws. The loco on my bench is a revision I, needing #620-8613-101 DC MOTOR / 0-6-0 DOCKSIDER SERIES-1, which is listed as not available. I tried searching the web for this part with no success.

 

Without a new motor, I guess I am sunk.

Still, I want to learn more about those power transistors. I see they are marked "247" and "TIP31C". There are four of them arranged in pairs. These are the components that I described as getting very hot in only a few moments.  From what I see on the web, they are rated to handle 3 amps.

 

CW, in my limited experience with the docksider series, the motor usually dies, and takes the reverse unit along with it. Since the loco isn't fun to disassemble, I would get both parts before disassembling. It has in the past annoyed my customers that a loco that only cost around $100 can cost $40 for parts that should last a lifetime. Then add the labor, and all of a sudden this is not an inexpensive loco. 

Thank you for the replies.

The cost of parts is adding up quickly.

I am going to check with the owner of the locomotive and see whether he wants to put that sort of money into the engine.

 

Rod mentioned replacing the power transistors on the reversing unit board. That would save quite a bit. Is it likely that replacing them would repair the board? Or would other components have failed with them?

I'vre repaired more reverse boards (all versions/types) than I care to remember, and have found that in over 90% of them it's usually just 1 pair of the Power Transistors that go.  However; that's not to say that something else could also be duff, just unlikely.  Unless all 4 Transistors are gone, you can  find the bad Transistors by comparing readings with an ohm meter (260 is great for this).  They usually short, which is very evident on the meter, and is why they often burn up as a result(component damage often obvious).  If you end up ordering parts from mouser or digi-key they are cheap enough that it's worth picking up a few extra just in case

r0d 

Off topic, but I bought the first version of these. Ran ok a few times then went to half speed as previous. Not repairable by cleaning or lubrication. Had been fed up for a long time with replacing Sound of Steam boards so I put the docksider away for a few years - when I took it out again one of the couplers had developed zinc pest after 5 years and was crumbling. Replaced the coupler for $14 with shipping and gave the engine away.

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