1960 Prima 1 Valve TV - Videokarma.org TV - Video

daro · #1 10-14-2005, 05:29 AM

I was reading about Madman Muntz & his gutless wonder TV's with at least 10 valves in his designs, Well I found a TV that uses just 1 valve in the design & it is from eastern Europe.

Chad Hauris · #2 10-14-2005, 06:28 AM

It looks like all the stages are there...probably would have to be very close to the transmitter to pick up anything, and you could only get one channel.
It appears to drive the vertical deflection yoke off the power line frequency but I don't see how the vertical sync signal is applied to the vertical system.

OvenMaster · #3 10-14-2005, 07:21 AM

Do my eyes deceive me, or am I seeing RF in one half of the vacuum tube near the antenna, with audio amplification in the other half, near the speaker? Is this a good idea? Lord knows I'm not a TV genius by any stretch of the imagination, but I'm curious as to whether or not this is common.
Tom

Don Lindsly · #4 10-14-2005, 07:07 PM

I suspect this schematic is a joke or a classroom exercise. There are several things "wrong with this picture". 1. The antenna circuit feeds the grid of the video amp. Where's the detector? No RF or IF gain at all says there's just not enough dBs to get anything done. The video output taken off the screen grid. The horizontal oscillator/output would be modulated by the video and the reverse.

Don't take it too seriously. It is not intended to work.

Don

Chad Hauris · #5 10-14-2005, 07:32 PM

This could have been used in a city where there was perhaps one government owned TV station. The selectivity would be in the antenna coil tuned for the one station. If you had say 500 kw of visual power from the transmitter, and were a few miles away, I'm sure you could get an O.K. signal with this little amplification. It could be perhaps an anode detector like is used in old TRF radio sets...no seperate diode is needed.

Celt · #6 10-14-2005, 07:54 PM

Actually, it looks like a TV schematic from the current offerings at Wal-Mart.

Sandy G · #7 10-14-2005, 08:45 PM

Heheheheh..Good one, Celt ! You don't know how right you are...to get those "low, low' prices Wal-Mart forces manufacturers to cut corners...you get what you pay for...their stuff works, but don't think it will be around for a long time...-Sandy G.

daro · #8 10-15-2005, 12:20 AM

Quote:

Originally Posted by Chad Hauris

This could have been used in a city where there was perhaps one government owned TV station. The selectivity would be in the antenna coil tuned for the one station. If you had say 500 kw of visual power from the transmitter, and were a few miles away, I'm sure you could get an O.K. signal with this little amplification. It could be perhaps an anode detector like is used in old TRF radio sets...no seperate diode is needed.

This TV is the Eastern Bloc equivalent to all those 2 & 3 valve TRF radios that were made in Nazi Germany before the WWII.

The CRT is more then likley a 5 inch judging by the EHT voltage, The set is more then likley made & sold very cheapley by the state as tool for spreading properganda by the state as was those radios in Nazi Germany.

I am trying to find out more info on this simple TV set on the net, But I have had no success so far..

Perhaps Telecolor 3007 might know somthing about these.

The website I d/l the circut was in Poland.

frenchy · #9 10-15-2005, 12:43 AM

I think I will wait for the 2-tubed color version...

wa2ise · #10 10-15-2005, 01:33 AM

Quote:

Originally Posted by Don Lindsly

I suspect this schematic is a joke or a classroom exercise. There are several things "wrong with this picture". 1. The antenna circuit feeds the grid of the video amp. Where's the detector? No RF or IF gain at all says there's just not enough dBs to get anything done. The video output taken off the screen grid. The horizontal oscillator/output would be modulated by the video and the reverse.

The cathode and G1 of the first tube looks like a Hartley local oscillator of the sort found in AA5 AM tube radios. Maybe the oscillation is partly locked on the signal's carrier and creates a synchronous detector? As for the horizontal oscillator, usually max RF on the carrier happens on sync tip. Which would be a big pulse when detected. Maybe that could "tickle" the feedback circuit between G4 and the plate of the tube? And create the horizontal deflection waveform and high voltage? But where does the vertical come from? Oh wait, it just assumes the vertical is the same frequency as the powerline, and you have to twiddle the hold knob to phase it in.

The sound is fairly straightforward, just an FM ratio detector detecting the FM subcarreir off the video.

daro · #11 10-15-2005, 02:31 AM

I have found the original article in the folowing download.

http://archiwa.elektroda.net/dwpl.ph.../60/04-60.djvu (This file is 8.8 Meg)

You will need a djvu plug-in for your web browser to view the file.

You will find the article on pages 21 & 22 & it is in Polish (We need this article translated by somone out there who knows Polish & can give us translation. )

andy · #12 10-15-2005, 10:50 AM

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