Re: Great Thread!, Discussion Thread to be established.
 

Eric,

If you have removed all secondary loads, i.e. tubes that use the filament windings, the rectifier tube, that uses the HV winding and can light a 100 watt lamp in series with the AC line input (primary winding) you either have a short in a socket on the chassis somewhere, or your transformer has a short inside. If it is the transformer, remove it from the chassis, take off the end bells and perhaps you will be able to find the short. For testing purposes the series lamp is great. You can also place 120 volts across the HV B+ winding and the transformer will be less stressed if there is an internal sort. If the xfmer is good you would read a voltage on the 120 volt primary winding which is equal to the step up ratio of the 120 to the HV. Maybe about 120 volts divided by six, or 20 volts AC, if the primary is good.

You really should have posted that question in the "My GE has a shorted power transformer forum"! :)

All,

I'm going to stick this thread to the top of the line and re-name it. It will be our own TV forum general discussion thread. Topics do not have to be TV related as long as they are posted by someone who have themselves, or personally know someone that has seen a TV, preferably of some vintage. Until I get a round tuit, please continue to post off-topic discussions here.

I do not know how one rates a thread, or where our 5 stars came from. I don't think those stars is anything bad though. :)

Thanx all for great conversations and posts.

Rob

Water
 

I'll pull the ends off this thing Monday at work ,I don't have a decent flat head screwdriver here at the house and those dang screws are tight!

I washed this set out with the hose, (see the attn:charlie thread)
and got some water inside the trannie, possibly this caused the short.

Originally when I powered it up the bulb would flicker and flash like the trans was frying. I baked it in the oven to dry it and now it's a steady light but far too much current is flowing.

I have a tranny from a 7" Admiral that might be about right, can't remember if it has a 5 volt winding though.

I have another from a KCS 47 RCA but it has about 375 volts coming out of it as opposed to the 275 called for in the GE, things might start popping with that much juice:p:

A transformer with a shorted secondary CANNOT be used in the circuit because the short is INSIDE the transformer and cannot be cleared by merely disconnecting the loads from the affected winding. If the short is in one of the filament windings, then the winding may be removed and re-wound since the filament windings are the outermost windings. Power transformer anatomy follows some simple conventions. The 120V primary winding is almost always the innermost winding, followed by the HV secondary winding, then the lower-voltage secondaries (bias windings - common in guitar and hi-fi amp transformers), then the filament windings. Rewinding an entire transformer is feasible, but it is quite time-consuming and very labor intensive. It involves taking the core apart and building a jig (rotating block with a crank - like a simplified fishing reel) to hold the windings. Slit the layers of paper, unwind and count the turns of each winding, take notes and make sketches. Obtain magnet wire of the proper sizes to match the original windings and use paper like the original (heavy Kraft paper) to separate the layers of windings. Neatness counts and it takes practice. Refer to "Construction Practices and Data Tables" section of an old copy of The Radio Amateur's Handbook. I have the 1975 edition which still featured a fair amount of tube data. I hope this helps.

xfmer troubleshooting.
 

John,

I was not suggesting that a transformer with a shorted winding could be used simply by disconnecting the load from that winding. I was merely trying to suggest a troubleshooting technique. A shorted socket, or other circuit fault can make the transformer look like it has a shorted winding unless disconnected from the transformer.

Are my communications skills that bad? :(

Rob

Addendum: Oh, I see that you must have been referring to CharlieT's reply. John is right Charlie. If any individual winding within the xfmer has an internal short to itself, the transformer cannot be used at all, unless this short can be found and cut open. Otherwise smoke will come out. Just disconnecting that winding from the circuit won't help.

Sure reduces confusion by addressing people by name don't you think? :)

Shorts
 

Ok fellas... I see where ya'll are coming from. Just out of curiousity, about how many hours does it take to rewind an average power transformer? Sounds like a good day's work! Perhaps rainy day activities.

winding your own xfmer
 

Charlie,

It may be that water got you in this trouble in the fist place. If you make a new transformer, do it on a dry day! :)

Actually if it went shorted because of water (washing the chassis)it is most likely the HV winding in which case I'd say forget it. Find a replacement. I don't make my own automobile tires for the same reason. My time is too valuable versus what it costs.

You might be able to save it though. Pull the end bells and look see. Sometimes it shorts where the connections are and can be quite easily repaired.

Rob