I doubt the AC line caps are drawing all that current. They'd of exploded by now with unlimited AC current flowing. You can simply snip one lead of those so they are out of circuit. They are not needed for the set to be operational.

Scratches head... how does 122 Volts @ .39 Amps equal only 7.3 Watts? :scratch2:

jr

Answer: power factor for this unloaded power transformer must be quite small, about 0.15 !

Just measured an unloaded tv power transformer of similar size on a kill-a-watt meter, readings were:
122 Volts, 0.26Amps, 9 Watts, 34 VA, 60Hz, 0.28 PF (power factor), so I believe that the PF could be as low as 0.15. :scratch2:
Did you happen to get a power factor reading?

jr

Here are my Kill-A-Watt Meter readings for my TV's Unloaded Transformer:

123.4 Volts AC
0.40 Amperes
8.2 Watts
50.6 VA
60.0 Hz
PF (Power Factor) 0.16

Hope this helps.

P. S. depending on the time of the day my voltage readings coming out of my outlets can range between 119.8 VAC and 124.5 VAC, when I took my Kill-A-Watt Readings just now my Voltage reading was 123.4 VAC when I took it this morning it was 122.5 VAC.

So, because of the low power factor of the unloaded transformer, the .40 Amp current draw does not appear to be excessive at all. Your transformer is behaving much the same as the known good transformer that I measured and is probably good.

jr

That's good to know and is basically what I was thinking.

So it definitely means that more than likely my problem lies with some bad paper caps in the TV that have shorted to ground more than likely.
Probably more than likely one of the paper caps that I have yet to replace.
Which I have already replaced almost half the capacitors in the set already, I have about 23 more capacitors to replace in this set yet (that includes some of the electrolytics that I haven't replaced yet in the set).

It's nice to see those reading off the transfomer. I was begining to wonder about a internal short as well.
Once those caps are changed it will make a big difference.
The heavy current load that was causing the rectifer to arc could have been partly due to some of the remainding old electrolytics trying to reform.
When they haven't had any voltage for long time they will pull a lot of current.

In the future it would be wise to power up a set like this with a dim bulb tester. That way you'll at least have a visual indication that there's excessive current being drawn before hitting the transformer with the whole shebang. Also make sure the set has the proper size fuse from the get go.

Ok, will do.
What size of bulb should I use on something like this?
I know certain size incandescent bulbs are no longer available.

You're right that large wattage bulbs are getting harder to find. Two or three 60 watts in parallel should get you in the range. You can experiment with a properly working TV to find the sweet spot were the bulb is just starting to light.

If you go through to various thrift shops, you'll find all kinds of incandescent lamps of all wattages. Many people stocked on lamps and now they're getting rid of them for LED's.

I found at my local supermarket a 150 watt incandescent bulb, would that work?

Thanks, I checked all my thriftshops near me and the biggest bulbs they had were 60 watt bulbs.

:thmbsp: Guys , check the shelves of your local Home Depot . For real .

Last week I was at HD looking for a specific bulb when I happened across these two 150 Watt bulbs for a couple of Dollars a piece . There were two on the shelf , so I bought two . I'd have bought as many as they had , thinking I'd stepped through some kind of time warp or something , but when I asked the guy in the electrical department he said they are a regular item , being so called "utility" bulbs they aren't subject to any kinds of restrictions .

:D you posted while I was typing , and as per my post above sure the 150 Watt bulb you bought will be fine .

¡Aye caramba! :eek: That won't give a soft start. Start with a low wattage bulb first, then work up in stages. Say 15W, 40W, 60W, 100W.

I found 150 Watt Incandescent Bulbs at my local supermarket.

Thanks for the suggestion though!

That's why I suggested testing different wattage's with a working TV a couple posts up. I suppose you could even use one of those 3 way switched bulbs for selecting different ranges. But I think a TV that uses 180 watts is going to drop too much voltage across a 15 watt ;)

I have a mogul base 3 way socket from an old floor lamp from the 1950s and a mogul base 3-way light bulb that's rated 100-200-300 watts, I could probably wire that up as a dim-bulb tester and just turn the 3 way socket on to the various wattages until the bulb dims when the set is on when it has been recapped, to check proper working order of the set.

200-300 watts would be too much for your set. I wasn't really serious about the 3 way. Like OC suggested just try different wattage bulbs starting with a lower wattage. A lower wattage bulb will have higher resistance than a higher wattage, which is why it will drop more voltage and provide a softer start. But if it's too low it also won't allow the TV to get enough voltage.

I also have a variac, but its currently not wired up, it needs a box, an outlet and a power cord. Anyone have instructions for wiring up a variac?

Pictures of the variac in question posted below.

The directions for wiring are printed right on the back, no?

Here's a pretty good tutorial on how the dim bulb tester works.

https://www.youtube.com/watch?v=zhQEP-Y_OUU

Yes, but I don't know whether or not a regular duplex style outlet would work with this variac setup or whether I would need to use just a single outlet for this setup, and I don't know whether or not this particular variac would support grounded wiring (grounded cord and grounded outlet), and how would I go about marking the voltage calibrations on the box for the knob once I got it wired up and installed in a box so I know what voltage I'm on when turning the knob.

I already have a general idea of how a dimbulb tester works, I just wanted some instructions on how to get my variac going so I could use it in the future, because I've never owned or used a variac before let alone wire one up from scratch before so that's why a little help would be nice in getting me started on wiring up my variac and getting running properly.

Single or double outlet don't matter...my factory made variac has a single outlet, but I plug a 3 way splitter in sometimes. It is a wise idea to put a circuit breaker on the input so if you plug a short into it it don't fry.

A good way to calibrate it once you have a box and knob with pointer is to plug a 40- 60w bulb in with a volt meter connected to the output. Every 10V make a line and label the output voltage every 5v make a dot. Best calibration would be with the input voltage at 120v or 125v. If you know you get say 50v at a knob position with an input of 120v you can take that ratio and mathematically determine the output if the line input voltage is something else.

A while ago I read the president got rid of that stupid law that was phasing out incandescent bulbs...We should see higher wattage incandescent bulbs return to store shelves. :thmbsp:

Didn't know that had happened. Sweet!

Thanks I'll give that a try. I'll definitely see if I can get my dim bulb tester and my variac wired up.

If you have an isolation transformer and some voltage and current meters you could probably build it all into one all purpose tube equipment power box...:thmbsp:

unfortunately I don't have any voltmeters or current meters and I don't have any isolation transformers either, and I don't know where I would get those things.

This rather inexpensive item solves a lot of the questions about current, voltage, wattage etc.

But the item above is not an isolation transformer.

If you have a pair of the same model appliance you don't mind scaping that draws 100W or more you can make your own isolation transformer out of a pair of step-down or step-up transformers.

Let's assume a 120V primary and that there is only one secondary (or only one secondary that uses a significant amount of power which will be the only secondary used). To make a bench isolation transformer out of 2 identical power transformers wire a power cord onto the primary of the first transformer, and a power outlet onto the primary of the other transformer, and lastly, connect the secondary of the first transformer to the secondary of the second transformer.

Do you shop thrift stores often? If so keep an eye out for those Uninterruptable Power Supplies used with computers. They look like shoebox-sized power strips. If you can find 2 of the same model they would be perfect. The secondaries are low voltage and beefy (use the secondary with thick wire). Those should be able to isolate a radio and most TVs easily.

I usually look for purpose-built isolation transformers at antique radio/ham swap meets rather than make them.

Here is another dirty trick based on the same principle. If you ever encounter a radio where the AC primary of the transformer has opened and you know the heater winding is 6.3V you can take a similar sized transformer with a 6.3V heater winding and connect it to the heater winding of the damaged transformer to power the set.

I'm not sure if all radio transformers would have that 6.3v filament winding of heavy enough gauge to support the total VA of the radio passing though it.

Its easy to find big fat toroidal transformers on ebay or Amazon. Many have multiple
115 volt windings that can be used as an isolation transformer or to make a step up or down 115-230 volt transformer. Some have lower voltage windings that can be wired in for small steps up or down and still have, unlike a Variac, isolation.

that's what I have and have been using, what I and Electronic M was talking about was an actual gauge that you had to physically wire into the box of the vairac and isolation transformer so you could monitor the voltage and current draw of the electronic device being brought up on the variac.

There's nothing wrong with using your killowatt meter in conjunction with the dim bulb setup. The reason for using the light bulb in series with the TV is to limit the current in the event there's some defective components.

Kill-A-Watt always goes first in the connection line. If not, it may not work/indicate.

I know. I was just trying to say that I had already been using a Kill-A-Watt meter this whole time.

If you want you can use the kilawatt with the box I suggested building one (as well as every other power device you would likely want) in to it because separate parts tend to get lost and not be there when one needs them...

I've been contemplating building such a box for years, but already having separates (and having an isolation trans short primary to secondary) and lazyness have stopped me.

Ok, that's what I was thinking of doing as well. But I wasnt sure that's what you meant as well.