Unnecessary complications in a tube colour tv

[boora2]

Got something out of a Frankenstein movie to fix for 2 nice old ladies,a Phillips K80 tv,110 degree deflection,twin channel push pull audio separate HV and scan trannys,HV capable of 40kV @ 100ma,4 PL519s in the Horizontal,high level tube demodulation in the chroma stage,got it working ok,40kV,.1A,wonder if those Dutch guys were smoking weed when they designed it,thing weighed a ton.

[lnx64]

Kinda hard to read, but, just cause it's heavy doesn't mean they were smoking weed, just means they built a tank to last.

[jr_tech]

I suspect that there is a misprint or poor translation involved here; 40KV at .1Amps is 4000 watts! A supply of that power rating could not be powered by a normal household plug. The set may be heavy and perhaps over-designed, but not 4000 watts!

jr

[lnx64]

Didn't even catch that.. Like those home stereos at the Flea Market that claim 2000 watts of power. Yet obviously impossible for a home outlet to provide.

[Electronic M]

Is this set presently located in the USA or some other country?

In places like Brittan there were multiple transmissions standards in place, and set makers often tried to make their sets compatible with them all....Thus leading to an over complicated product.

[Username1]

Originally Posted by jr_tech

I suspect that there is a misprint or poor translation involved here; 40KV at .1Amps is 4000 watts! A supply of that power rating could not be powered by a normal household plug. The set may be heavy and perhaps over-designed, but not 4000 watts!

jr

Remember its not a continuous flow of current, but rather pulsed, and a very narrow pulse, small duty cycle, the tube acts like a big cap, and smooths it out....

But at any rate there is a misprint in there, most HV supplies are at around 40ma or less..... But even that is pulsed, small duty cycle, the meter may "indicate" 40ma, and read it that way, but use calculus and it may be much less....

[Electronic M]

Originally Posted by lnx64

Didn't even catch that.. Like those home stereos at the Flea Market that claim 2000 watts of power. Yet obviously impossible for a home outlet to provide.

Actually most breakers are rated at 20A, and 20A*120V=2400W so a 2000W amp is technically possible on household power.....

[lnx64]

Huh. Definitely not how they are constructed though and with the puny little 2 prong wire..

[Electronic M]

Originally Posted by lnx64

Huh. Definitely not how they are constructed though and with the puny little 2 prong wire..

I'm not saying that what you saw was actually realistically rated, just that it could be done. I know what you mean about over rated audio amp powers; Two 7watt Heathkit tube monoblocks I have can blow a newer 250W Sony stereo I have out of the water easily. Audio wattage rating standards in the last few decades have become more of a marketing sham than the actual legitimate scientific measurement they once were.

[lnx64]

When I say over rated amp power, I mean the highly unrealistic number slapped on. What about 2000 watt amps in a car? I doubt the alternator in my car could push that.

[zeno]

In the olden days everyone used a different formula to
figure watts. The cheaper the unit the more exaggerated
the claim. Electrophonics were often 200W "peak music power".
Probably more like 5W per channel. IIRC in the late 70's
rules were passed standardizing things to RMS power.

73 Zeno

[dieseljeep]

Originally Posted by zeno

In the olden days everyone used a different formula to
figure watts. The cheaper the unit the more exaggerated
the claim. Electrophonics were often 200W "peak music power".
Probably more like 5W per channel. IIRC in the late 70's
rules were passed standardizing things to RMS power.

73 Zeno

They used to rate it by IPP. Instantaneous peak power.
It was rated at 100 watts, but it only had output transistors, similar to SK3004.

[zenith2134]

I have some early solid state Lafayette and Pioneer gear which states audio power in "PMPO", Peak music power output.

[zenith2134]

Back to TV discussion, I've seen many over-designed sets. With tubes, the color demod circuitry can be a pain to trace out and repair. but the power supplies. I notice that as TVs got lighter over the years, the switching supplies got more complicated in general. No longer do we see a big transformer with secondary taps and smoothing capacitors connected to diode rectification. Sonys had a lot of proprietary ICs in the Trinitron PSUs which made the set BER for the consumer. Shame to junk a set when the tube is still in good shape.

[old_tv_nut]

That must be 100 microamps. No CRT runs at 100 milliamps beam current.