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  #1  
Old 02-27-2018, 07:28 PM
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init4fun init4fun is offline
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The world's smallest Vacuum tube TV bar generator ?

Well , maybe not the smallest , but I've never seen one smaller . This uses 1 tube , a 12AT7 , and a selenium rectifier with an assortment of the usual resistors , caps , and coils . I haven't yet tried it , but I can't imagine it being all that useful next to my 1077B .
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Old 02-27-2018, 09:13 PM
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MadMan MadMan is offline
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Neat. I'd like to see what it does.
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Old 03-03-2018, 11:12 AM
dieseljeep dieseljeep is offline
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Originally Posted by init4fun View Post
Well , maybe not the smallest , but I've never seen one smaller . This uses 1 tube , a 12AT7 , and a selenium rectifier with an assortment of the usual resistors , caps , and coils . I haven't yet tried it , but I can't imagine it being all that useful next to my 1077B .
I have something like that in my collection of odd-ball test equipment.
RMS made some real cheap & nasty equipment. Superior and Accurate Instrument also made a lot of it. Advertised on the Back of Popular Electronics magazines. Some electronic parts houses sold it as well.
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Old 03-09-2018, 06:57 PM
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init4fun init4fun is offline
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Originally Posted by MadMan View Post
Neat. I'd like to see what it does.
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Originally Posted by dieseljeep View Post
I have something like that in my collection of odd-ball test equipment.
RMS made some real cheap & nasty equipment. Superior and Accurate Instrument also made a lot of it. Advertised on the Back of Popular Electronics magazines. Some electronic parts houses sold it as well.
MadMan when I finally hook this thing up to a TV I promise I'll post up a picture of the results . I believe like dieseljeep says , this thing looks like a cheap and nasty piece that will likely produce something more akin to "hum bars" than any kinds of accurate , useful for TV adjusting bars .
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Old 03-11-2018, 04:39 PM
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Kevin Kuehn Kevin Kuehn is offline
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Could be it's nothing more than a audio frequency(vertical) and a RF freq generator(horizontal) that beats against the sets scanning oscillator frequencies. That neon lamp on the front may even be used as the trigger in a saw tooth relaxation type oscillator. I've done the same using my function generator and it actually works very well for linearity adjustments. Be aware that such a simple piece as you have there likely does not use an AC line isolation transformer. It would be very wise to have the set under test powered through an isolation transformer.

Last edited by Kevin Kuehn; 03-11-2018 at 05:25 PM.
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Old 03-12-2018, 06:38 PM
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init4fun init4fun is offline
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Originally Posted by Kevin Kuehn View Post
Could be it's nothing more than a audio frequency(vertical) and a RF freq generator(horizontal) that beats against the sets scanning oscillator frequencies. That neon lamp on the front may even be used as the trigger in a saw tooth relaxation type oscillator. I've done the same using my function generator and it actually works very well for linearity adjustments. Be aware that such a simple piece as you have there likely does not use an AC line isolation transformer. It would be very wise to have the set under test powered through an isolation transformer.
Thank You Kevin , and yes indeed I intend to run it (the bar generator) on my isolation transformer and the TV I'm planning to connect it to is one of those little 5" B/W portables that takes a zillion D batteries and luckily has an antenna input . It's now just a matter of me digging out that little TV ...
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Old 03-20-2018, 10:13 AM
dieseljeep dieseljeep is offline
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Thank You Kevin , and yes indeed I intend to run it (the bar generator) on my isolation transformer and the TV I'm planning to connect it to is one of those little 5" B/W portables that takes a zillion D batteries and luckily has an antenna input . It's now just a matter of me digging out that little TV ...
I just looked up the Heathkit version and it's similar, with the single 12AT7.
It's a little larger and does have a transformer for full isolation.
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Old 03-22-2018, 01:35 PM
radioal radioal is offline
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Originally Posted by dieseljeep View Post
I just looked up the Heathkit version and it's similar, with the single 12AT7.
It's a little larger and does have a transformer for full isolation.
It was apparently heathkit policy to use transformer power supplies in all tubed gear. I guess to minimise the number of kit builders they killed. I've even seen an aa5 am radio with parallel filaments and a transformer. They did things right.

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