Con-Cor 4-6-4 modification

[peteski]

ah peteski,
I thought that typo was funny and I liked it.

That was cute Victor. I guess that I removed your point.  But I thought I would fix it, not to confuse someone in the future.  The original version is still in the quote of your post.

[Doug G.]

Gosh, I didn't even notice Pete's typo. I guess I must have thought it looked OK. I mean, I was just going to make sure I never got any isopropanol on the tip of an X-Acto #11 again.



Oh, and BTW, isopropanol, and probably other types of alcohol, can be used to dissolve Dullcoat.

Doug

[nickelplate759]

An update -  as I was assembling the loco shell onto the chassis, I realized something that I should have noticed a LONG time ago.
The engine is supposed to pick up current from the drivers, the pilot truck and the trailing truck (I knew that much).  However, all the contact points (in the pilot and trailing truck frames, and where the bearing blocks insert into the frame, are painted!

I don't know how I missed that!

Since it runs great now, with pickup almost entirely from the tender, I'm going to leave it alone (don't fix it if it's not broken!), but I thought I'd mention it in case someone else is rebuilding one of these (Chinese-made 4-6-4).

George

[mmagliaro]

When you flip the engine on its back and run it with clip leads at the workbench, will it run when you touch
the probes to the drivers? 

[nickelplate759]

Yes, but with relatively poor contact.  If I have to disassemble it again I'll be sure to remove all the paint from the slots the bearing blocks ride in.

If I put leads to the pilot truck and trailing truck nothing happens.  They're fully insulated with paint.
The tender pickup now works so well that the engine runs very well when attached to its tender.

George

[mmagliaro]

That's good information, George.  Thank you.
I'm used to seeing this on brass steam all the time.  Those folks just paint over everything.  I'm a little surprised to
see it in a plastic production model, but I guess I'm not too surprised.

[nickelplate759]

Well, it's not a good night with the Hudson.  I finally put it all together.  First, I broke a little corner of the tender skirt  .  I can mostly fix that so it won't show.

Second, after I got it all together, the DCC doesn't work right any more. It's a TCS M1 decoder.

 Here are the symptoms:
1.  Works fine on DC
2.  Worked fine initially on DCC - something appears to have happened during final assembly. It worked with the engine body (but not the tender body) on yesterday.
3.  When I turn on DCC power (I'm using a SPROG II here), but do NOT move the throttle, the engine makes a buzzing noise and runs backwards moderately slowly.  I if move the throttle it will usually stop, but it won't respond to the throttle.
4.  This happens if power is supplied only to the tender.
5.   It happens if power is supplied only to the engine (no tender attached)


I suppose I could I have worked a wire loose and caused a short, but would that cause this behavior?

Any thoughts?

George

[victor miranda]

that movement makes me very unhappy.

It implies a short or a FET failed.

.... the fix is the same if my thinking is correct.  replace the decoder.

double check insulation to the motor leads
and try again.


luck!
victor

[Doug G.]

Even though the pilot truck can contribute to current pickup, it's not very reliable because there are no spring or other pressure type contacts. It's just metal against metal and depends on happenstance to maintain contact where the truck attaches to the frame.

The trailing truck can't contribute to current pickup because the truck frame is plastic where it attaches to the frame. The wheels are mounted in metal but that part of the truck frame is isolated since the side frames and front part are plastic.

I don't think these factors are too much of a negative, however. Both my Chinese versions run very well with no hesitation, even on plastic frog turnouts. Pickup from both sides of the drivers and both sides of four sets of wheels on the tender seems to be enough

Doug

[nickelplate759]

I took off the shell to have a look at the decoder, the short went away and the decoder worked fine.
My friend Murphy then pointed out a few places where I hadn't felt it was necessary to cover some bare contact points, 'cause I didn't see where they could short out on anything (hah!).
I wrapped them up, tested the engine, put the shell back on, and it works fine.

Guess it was my lucky day, and once again I learned something.

George