Hi,

Is it really dead? Newer versions of this transformer don't reset automatically after a short-circuit. It only resets if you unplug it for a short time.

Regards

Markus

Hi,

Regarding the second Transformer ( red Knob problem ) is it a #6646 ? . The wire which connects the Knob to the Slider inside the Housing is probably broken from moving the Knob a lot. I have seen this before.
When the Transformer is assembled some time they have the Wire to tight and it will break after a while.



It always amazes me that this never happened to the Old blue Transformers.

Martin

Sorry Dr D. No Fuse in that transformer (overload Circuit Breaker).

Martin

Not really giving us a lot to go on here, we need to know the specific trafo first, the number will be underneath, ie 66xx.

And you need to be aware that opening the Trafo exposes the high-voltage wiring - yes of course you'd do this with the power off, but it's what someone may or may not do in their repair attempt which poses the danger. This of course is at your own risk. Now with the disclaimer out the way....

If it's assembled in the style of similar units (ie 6646 as below), there are two plastic plugs on each side which need to be extracted.

I'm not sure of the 'factory' method to remove those plugs, but it could involve either a real powerful suction tool, or more likely simply drilling them out and fitting new ones when done.

I remember seeing a procedure for this online (with pictures) but I simply cannot find it to re-post here - if someone else knows.... bring it on.

One thing you could try depending on what tools you have is to drill a fairly small hole right in the center, then try to screw a slightly larger self-tapping screw with a sharp point into the plug until it grips and then pull it out. Quite likely you'll find the plug will simply turn in the hole and that can be quite frustrating so you might need to jam a sharp jeweler's screwdriver or similar against the plug to hold it. Oh, and of course you need at least three hands for this

If you're not really bothered about cosmetic appearance, you can also kind of pry them out with a pair of box-cutter blades or similar, yep it's brutal, and will make a mess of them, and you might also lose a finger-tip or two, but that's all part of the fun yes?? And that's what I had to do many years ago when I had to open my Central Control, and had no suitable drill bits at hand. I did get them out.

Failing that, simply drill them out altogether, but be VERY careful not to drill any further into the unit than the length of the plug, which of course you don't know, but I think from memory is no more than about 1cm. As for securing it after attempted repair, you could just use ordinary self-tappers or similar. Drill bit size should probably be about 2 sizes smaller than the plug itself otherwise you drill out the housing and you don't want that.

Gripping and pulling the plug is what you really want.

Someone is bound to post a more elegant solution than this so hold off for the time-being.

Best

Steve

Thanks - yes the transformer is a 6646.

I see the plugs and will attempt the extraction.

Sorry about the repeated pics

I haven't had the chance to work on it yet. I need to go through my bin of wires to find a nice, small flexible piece to patch in. I don't want to solder the original back together just to have it pinched at the solder point. Perhaps I can attach it via another means ( looks as thought that white rectangular clip holds the wire in place so it doesn't fall down onto the contact copper).

I may have to get some smaller solder - I want to use minimal heat and a few heat syncing alligator clips so I'm not overheating any sensitive components. I don't want to creat additional problems.

I'll work on it and send some pictures along.

Any suggestions are welcome.

Wow, thanks both. I'm interested in how it turns out. None of my White 6646 transformers ever turn as smoothly as my old 6627 transformers (as Hoffman indicated). I have one I know needs this repair (although I have yet to take it apart), and I feel like as time progresses with my other 6646 I may have to do this repair again. At least the overload protection on the new white transformers is nearly instant, much better than the older 662x units.

Like you, I have some young kids who sometimes move the knob quickly and side to side. This is especially a problem if there is no train on the track for some reason, as they expect the movement and don't get it. I teach them as it goes, but when you are very young you are still learning patience and finesse so it takes time.

-Brandon

More pics

G

Mike,

Thank you for the offer, I'll let you know. You've given us such good pictures, I don't think it should be too much of a problem to give it a go. I just have to get around it to, right now the 6646 I have in this state is a spare...but plans to do things, would help to get this one running again. Glad it worked out!

-Brandon