Zenith Custom 23 Super H Chassis: FIXED

[Coshi]

OK, So my farther had a variac in a box of eletrical junk in his car. Problem salved.
Thanks for the diagram though.
I may make one of those aswll

[DavGoodlin]

Originally Posted by maxhifi

Formula to calculate voltage. If you have a transformer with other than 12.6v secondary just substitute this in the equation.

Thanks for the idea to make a "buck" transfomer. A 2 amp secondary is just right for this Zenith.
Would it then be safe to assume the secondary winding current should match the current (amp) draw of the actual appliance or TV used?

[NoPegs]

Originally Posted by DavGoodlin

Thanks for the idea to make a "buck" transfomer. A 2 amp secondary is just right for this Zenith.
Would it then be safe to assume the secondary winding current should match the current (amp) draw of the actual appliance or TV used?

Match or exceed. Never less.

[old_coot88]

Originally Posted by maxhifi

Use a bucking transformer, see attached images for the circuit. If you don't get the results you expect, swap the two secondary lead connections and it will work.

I woulda thought the bucker would be wired this way..
Attachment 183433

[maxhifi]

Originally Posted by old_coot88

I woulda thought the bucker would be wired this way..
Attachment 183433

You have it wired as a bucking transformer, I actually wired it as an autotransformer (and called it a bucking transformer, which is a mistake), I think either way should work. Yes the secondary of 2A I picked for the average tv, a big colour set could use more, say 3A. You could make a really big one from say an old car battery
Charger.

[maxhifi]

One additional bit of info. I picked an autotransformer connection almost without thinking about it, because it's commonly used to use 240V loads on a 208V service and vice versa. I did a little reading about the true "bucking" connection (where the windings are connected out of phase) and found the following thread

http://www.antiqueradios.com/forums/...49657&start=20

Their conclusion seems to be that the autotransformer connection as I drew it is more efficient than the bucking connection as old_coot88 proposed, however either will work.

So basically, in conclusion, if you need to operate vintage electronics and have a utility who is giving you a stupidly high line voltage, connecting a cheap 12.6V filament transformer as an autotransformer and using it to reduce the voltage is an excellent option. It is cheaper than a variac, and in fact is cheap enough you could leave it permanently attached to a specific TV and leave your variac on the test bench where it belongs.

**safety note** The secondary windings of a small transformer may not be insulated as well as the primary. For this reason, I would mount the transformer on a wooden or otherwise non-conductive base, just in case the case of the transformer ever became "hot". Yeah it probably won't happen, but we're using something outside of what it was originally designed for so may as well be careful.

All the same though I would want to get to the bottom of why my line voltage was so high, a call to the utility is in order, since the approach of using a voltage adjusting transformer is really treating the symptoms rather than the problem. You live in the USA, it's supposed to be the best electrical infrastructure in the world... 137V is absolutely not acceptable, and it is possible that the utility will even appreciate it that someone has made them aware of a problem with their system.

[DavGoodlin]

Originally Posted by maxhifi

One additional bit of info. I picked an autotransformer connection almost without thinking about it, because it's commonly used to use 240V loads on a 208V service and vice versa. I did a little reading about the true "bucking" connection (where the windings are connected out of phase) and found the following thread

http://www.antiqueradios.com/forums/...49657&start=20

Their conclusion seems to be that the autotransformer connection as I drew it is more efficient than the bucking connection as old_coot88 proposed, however either will work.

So basically, in conclusion, if you need to operate vintage electronics and have a utility who is giving you a stupidly high line voltage, connecting a cheap 12.6V filament transformer as an autotransformer and using it to reduce the voltage is an excellent option. It is cheaper than a variac, and in fact is cheap enough you could leave it permanently attached to a specific TV and leave your variac on the test bench where it belongs.

**safety note** The secondary windings of a small transformer may not be insulated as well as the primary. For this reason, I would mount the transformer on a wooden or otherwise non-conductive base, just in case the case of the transformer ever became "hot". Yeah it probably won't happen, but we're using something outside of what it was originally designed for so may as well be careful.

All the same though I would want to get to the bottom of why my line voltage was so high, a call to the utility is in order, since the approach of using a voltage adjusting transformer is really treating the symptoms rather than the problem. You live in the USA, it's supposed to be the best electrical infrastructure in the world... 137V is absolutely not acceptable, and it is possible that the utility will even appreciate it that someone has made them aware of a problem with their system.

Most utility companies have in thier public utility tariff (binding agreement) a requirement to supply no more than 5% deviation from 120 volts.

[NoPegs]

Originally Posted by maxhifi

All the same though I would want to get to the bottom of why my line voltage was so high, a call to the utility is in order, since the approach of using a voltage adjusting transformer is really treating the symptoms rather than the problem. You live in the USA, it's supposed to be the best electrical infrastructure in the world... 137V is absolutely not acceptable, and it is possible that the utility will even appreciate it that someone has made them aware of a problem with their system.

Originally Posted by DavGoodlin

Most utility companies have in thier public utility tariff (binding agreement) a requirement to supply no more than 5% deviation from 120 volts.

9 months out of the year I'm up around 129 volts, just this week the 24 hour average voltage measured at 1 hour intervals by my UPS was <125v due to the whole hot and humid things happening outside. By the first week of August it'll be 119, then start climbing again when things eventually cool off.

Where I'm at the stated SLA is for 120v +10%/-5% and 60.0Hz +/- 0.1%, so anything under 133 is considered "Acceptably high, but within spec." and honestly I don't mind it for anything other than light-bulbs. Thankfully, 130V bulbs are actually a thing and they're not priced differently than normal bulbs, but if I ever decide to abandon incandescent light, I know that CFLs tend to go BANG after a month or so here. I should actually remember to get some LED based bulb-substitutes when I find myself in PP&L territory and see how they do on 130v. (I bet they're fine, maybe a 3% reduction in total lifetime which is probably 10k hours or more to begin with.) PP&L does the energy saving bulb subsidy right at the register at almost all chain retailers in their territory, silly Met-Ed (First Energy) either wants you to buy the ones they'll sell, or send in the receipt and UPCs for credit on a future bill if you buy your own less craptacular units.

I live about 1900 feet from the substation, and it just happens to be what feeds a Bayer process plant, and an asphalt shingle plant, plus about 100 residential customers on that end of the borough. Power doesn't go out often for me, but if the main population's grid goes down, I lose internet if its down for more than about 2 hours or so. Cable HFC feed comes in from about 20 miles east, and either the FTC node or one of the two line hybrids in the RF chain before my tap comes up short on the backup power department. The only downside I can find to being part of the medium industrial grid is the hotter potential.


Something to contribute on this one, for Coshi, with nearly 140 ( ) volts:

Are you fed with the normal split-phase service or the silly bi-phase service seen in some older multiple dwelling units? Split phase is 240v center-tapped and ground-bonded neutral service(2 hots and a neutral with 180 degree phase angle on the hots.), bi-phase is still 2 hots and a neutral, but hot-hot gives ~208 instead of ~240 because of the 120 degree phase angle difference.

If you're unlucky enough to have bi-phase service, are all your outlets >130v, or just the one you've measured so far? Twice before I've poked around and found that a place wired with bi-phase somehow got changed at the pole to a high-leg delta type setup through some horrible series of errors, and half the outlets got 0.66*208v instead of 120v, which based on the measurement you provided actually seems to be a plausible case here. (137 is near enough to precisely 2/3 of 208v, remember there's a phase angle difference involved.)

Now I'm interested in seeing if you're the third example of this issue I've been party to.

[maxhifi]

I get dead on 117 - 120, whenever I measure it any time of year, any time of day.. I suppose I should consider myself lucky.

[Coshi]

OK! So called the power company they came and sorted it all out.

I figured I'd check the plugs in the house and found the plugs downstairs where around 200+ nothing had been plugged in down there since the fire. I called the power company right away.

[maxhifi]

What was wrong? My vote is for a bad neutral connection somewhere between the electrical panel and the transformer.

I hope you tell people how owning an old TV PREVENTED a possible house fire, by bringing attention to the electrical issue!

[Coshi]

The neutral was hot. Thats what the tec said.

ALSO I thinks its very funny that a vintage TV, Things known for bursting into fire. Saved the house from a 2th fire.

[Kamakiri]

Wow. All of a sudden, I feel very good about turning down a higher local offer on that TV and sending it to you. That's one of those things that was meant to happen

[Coshi]

I know! I'm so happy you sold it to me too. You did A lovely job, The only thing I cant figure out is the wavy picture.

Other then that, With everyone in the house watching it it only goes off for 4-6 hours a day! with that much use I figured it would eat through its picture tube pretty quickly. SO I put feelers out for a spare picture tube and got one for a whooping 20$ !! I also got a brightener for when it goes out. I got them in a box with all the other spare parts a got from the Toms Radio.

Again thanks SO SO MUCH!

So yea it goes on at 4am when my mom gets up for the news, My dad gets up shortly after to watch the weather and the history channel then he goes to work, By then I have gotten up and I watch dirty jobs and I love Lucy. by then I head off to work, THEN my brother turns on the sports and what ever he watches. Then 2pm rolls around my mom comes home she then turns on Bones and resolie and Iles. I get it after her for the daily rerun of My little pony. and then my dad comes home and watches duck dinsty or somthin as well as some other stuff, and the set goes off around 10pm or 12am

So it defnally gets used. It ant' No museum peace! : )

[Kamakiri]

Now that you've got your line voltage situation figured out, might not be a bad idea to run through the tubes. I tested them all and replaced one or two that were marginal before it headed out the door to you. Could be a weak horizontal AFC or sync separator tube.

That set'll last you a good long time. I used it nearly every day for six months. I actually found a brand new vertical output transformer that I bought for the set but never needed. PM me your address and I'll put it in the mail, along with some spare tubes if you need them, just list off the tube numbers in the PM