View Full Version : Owning & Caring for Vintage Colors


Arcanine
09-12-2015, 11:53 PM
I've been meaning to make this post. I am on the verge of getting my first Roundy. Despite a lot issues with my truck setting back plans or totally changing them, and other issues with space in my home, I'm going to be bringing my first color roundy home tomorrow.

I don't know the year, as I have forgotten to ask, but it is a Zenith set. In working condition, with a strong tube and a good picture. It has the A/V modification, which I am perfectly okay with. It saves me having to run my Modulator anytime I wish to use it.

I've owned various tube black and white sets over the years, and I owned a Toshiba color for awhile which I used, despite it being a very finicky set.

What should I know about using one of these sets on a fairly regular bases? I do plan to watch, and enjoy it. I'm not buying it to sit in a corner and be a display piece, I am getting it to watch classic television on, and get enjoyment from.

As such, I have never owned a tube color set as old, or as large as one like this.

Any advice for my first, and probably only set I'll own like this? (Strong space constraints. I had to do a lot of work to give this set a comfortable place to live in my room)

Phil Nelson
09-13-2015, 12:30 AM
If the set has been thoroughly and competently restored, I don't think extreme measures are needed. I have restored various color roundies over the years, and my approach is to turn them on and enjoy them. These sets were designed to withstand regular -- often daily -- use.

If you want to be conservative, you could run it through a variac or a "humbucking" transformer that reduces the line voltage to around 117 volts AC, which is the voltage usually specified in the service manuals for these sets. Depending on where you live, the line voltage may run as high as 123 - 125 volts. Dialing back the voltage a few volts might reduce the stress on your set and help its reliability over the long term.

Or, possibly that small percentage difference in the line voltage doesn't really matter. If you visit the Early Television Foundation museum in Ohio, you'll see a number of rare & valuable TVs on display, many of which are played for demonstration at conventions or whenever. As far as I recall, they just turn 'em on, without any special voodoo.

Just my $0.02 . . . .

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

miniman82
09-13-2015, 02:37 AM
True, but if you know the museum like I do having that many vintage sets running at the same time has about the same effect on the line as a variac does...


I can tell you that some sets do not like high line voltages, some don't care. I had a portacolor and you could run it normally no matter what the line voltage was, because of the type of HV section it had. Early RCA sets don't like high input voltages, because they can and often will cause the flyback to run hot. You can verify by monitoring horizontal output tube cathode current at various line voltages, the worst offenders are sets with silicon B+ rectifiers because they are more efficient than a vacuum tube. It's not hard to go out of spec on horizontal output current, and when you do it's not hard to burn out irreplaceable parts. I'm anal and don't like looking for unobtanioum flybacks, so I never run a set for extended periods without a variac.

Zenith sets tended to be more robust than RCA, so I personally wouldn't worry till line drifts past 120. But again, only way to know if you're in the 'flyback melting danger zone' is to read horizontal output cathode current, and if it's higher than called out in the schematic don't be surprised if things get too hot.

Findm-Keepm
09-13-2015, 06:10 AM
True, but if you know the museum like I do having that many vintage sets running at the same time has about the same effect on the line as a variac does...


I can tell you that some sets do not like high line voltages, some don't care. I had a portacolor and you could run it normally no matter what the line voltage was, because of the type of HV section it had. Early RCA sets don't like high input voltages, because they can and often will cause the flyback to run hot. You can verify by monitoring horizontal output tube cathode current at various line voltages, the worst offenders are sets with silicon B+ rectifiers because they are more efficient than a vacuum tube. It's not hard to go out of spec on horizontal output current, and when you do it's not hard to burn out irreplaceable parts. I'm anal and don't like looking for unobtanioum flybacks, so I never run a set for extended periods without a variac.

Zenith sets tended to be more robust than RCA, so I personally wouldn't worry till line drifts past 120. But again, only way to know if you're in the 'flyback melting danger zone' is to read horizontal output cathode current, and if it's higher than called out in the schematic don't be surprised if things get too hot.

+1 to the above. My dad (a TV tech for ~50 years) used to say the worst you could do to a TV was to turn it off - they want to be on....

I've got high line voltage (127V most days), but never run a variac - I have a Sola power line conditioner (thank you DoD surplus!) that I use. My entire bench is wired through it now, and no matter the input line voltage, the output is 118V, and it also smooths it, running the juice through an EMI filter. Heavy, yes, but no having to set a variac. I have a smaller (still heavy!) one here in the house that I use for my sets.

One additional benefit - my bench lamp bulbs last a long time and my bench DMM (an old 70's Racal Dana) doesn't "hunt" with no input.

Olorin67
09-13-2015, 03:12 PM
one easy way to to reduce the volts a little is to plug it into 50 foot of extension cord (cheap walmart variety best) and that will drop 2-5 volts under load. most sets have enough space to coil the cord underneath.

Alastair E
09-19-2015, 06:43 PM
one easy way to to reduce the volts a little is to plug it into 50 foot of extension cord (cheap walmart variety best) and that will drop 2-5 volts under load. most sets have enough space to coil the cord underneath.

Err--REALLY!!

Are you really for real!

That advice is the worst Ive ever seen on Any forum--EVER!!

What you advise (coiled up extension-lead to drop voltage) is a recipe for a FIRE!
--A fire--Under/in what may be a prized TV set--surely would cut short its life faster than a couple of extra line-volts, and may even end the life of its owner too!!

Alastair E
09-19-2015, 06:52 PM
If you want to drop voltage safely, use a Transformer. 120V Primary (or to suit your line-voltage) and secondary the amount you need to drop.

Wire primary to line, and secondary in series and in anti-phase to the line, so drops by the secondary voltage to the set. Choose a suitably rated transformer secondary current, say double that consumed by set.
--Will give better regulation than daft coiled extension-lead and a Hell of a lot safer, could be made as a permanent fitment inside set if required.

Username1
09-19-2015, 07:55 PM
With any old sets, and I do this for my '80's Sharp Transistor sets, Once a year I open
them up and vacuum, or blow them out with an air gun. Get all the dust that in this area
along with high summer humidity can cause - or leave the door open to arcing, or
paths to current flow, arcs near flybacks, yokes, etc.... I do it as a precaution,
I don't know if it's a requirement, or necessary, I just think it's worth the effort....

.

old_tv_nut
09-19-2015, 09:26 PM
I wouldn't be so paranoid about using a long extension cord - after all, it's only dissipating a few watts at most, while the chassis in your set is dissipating perhaps 300. But, the cord drop is not adjustable, and you really would like to get the input down to the 115-117 range and know that's where it is. So, a variac is much preferred.

My gut feeling about safety with these old sets, even if well and fully restored, is don't run them out of sight. You want to know immediately if something fails. Otherwise, enjoy!

zeno
09-19-2015, 10:01 PM
On the fire issue in almost 40 yrs of TV repair I have
never seen a set go into open flame burning. We saw
plenty of dried up junk but never a fire. Things burned
but it always was limited. FBT's & triplers could be
spectacular but it stopped there. Resistors glowed white hot
& smelled like dog doot. Rooms filled with acrid smoke.
But never a real fire. Yes you could light your smoke
on it.

Bottom line is just dont leave things old running when you
go. Just like burning brush. Use a little common sense.
The crude extension cord isnt much of a risk. They do
have a voltage drop so a little heat. Feel any cord moving some
watts & it will get warm.

73 Zeno:smoke:

Jon A.
09-19-2015, 10:34 PM
Resistors glowed white hot
& smelled like dog doot. Rooms filled with acrid smoke.
But never a real fire. Yes you could light your smoke
on it.

73 Zeno:smoke:
You've done this? If so, high-five!

Electronic M
09-20-2015, 01:07 AM
All modern extension cords I've seen are rated 1250W or more. A 350W (hell even some of the early beasts that drew 415W) TV ain't even half way to the max rating of the cord....Most extension cords have much more copper in them per foot than the set's original cords (which most here use when not damaged) so I'd be more worried about the set than the extension cord....
IIRC it was miniman who accurately said that if you run multiple sets at the same time it will often shave a good number of volts off the line....Could not agree more!

Zeno if you've lit your smokes off a red hot part, your the man!....Closest thing I've done is to take a plasma speaker made form an old SS flyback a 555 and a power FET and lite a cig.....I might have been playing Boston's "Smokin' " on the arc when I did. :smoke:

If my plasma speaker ever goes beyond a breadboarded toy I'll have to put some metal studs in my pipe so I can add lighter functionality to it.

miniman82
09-20-2015, 09:26 AM
Tom,

CTC-2B draws 525 if memory serves, quite a lot of power for only a 21" picture.

zeno
09-20-2015, 09:50 AM
You've done this? If so, high-five!

Actually the Weller gun also lit cigarettes & degaused.

73 Zeno:smoke:

zeno
09-20-2015, 09:56 AM
You've done this? If so, high-five!

I forgot. We also had a big heat gun. Worked better but you had to
be careful it could melt your hair.

73 Zeno:smoke:

old_coot88
09-20-2015, 03:28 PM
On the fire issue in almost 40 yrs of TV repair I have
never seen a set go into open flame burning.
73 Zeno:smoke:
There were some full-blown fires including house fires caused by RCA CTC-25 power switches arcing. RCA issued a preemptive upgrade and we installed the new switches on every '25 that came thru the shop.

We had a trade-in cheapy 'suitcase' record player (xtal cartridge, 50C5 and 35W4, tapped motor winding for heater dropper), no fuse at all. It had a bad filter cap (about a 50/30 at 150V, wax coated tubular) that was running hot. For a 'controlled experiment' we let the thing run to see what would happen. The cap began smoking, and did go into open flame fed by the wax. Shudderd to think if the thing was in somebody's house and left on.