Videokarma.org TV - Video - Vintage Television & Radio Forums

Videokarma.org TV - Video - Vintage Television & Radio Forums (http://www.videokarma.org/index.php)
-   Diagnostic & Test Equipment (http://www.videokarma.org/forumdisplay.php?f=177)
-   -   The world's smallest Vacuum tube TV bar generator ? (http://www.videokarma.org/showthread.php?t=270197)

init4fun 02-27-2018 07:28 PM

The world's smallest Vacuum tube TV bar generator ?
 
1 Attachment(s)
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 .

MadMan 02-27-2018 09:13 PM

Neat. I'd like to see what it does.

dieseljeep 03-03-2018 11:12 AM

Quote:

Originally Posted by init4fun (Post 3196769)
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. :scratch2:

init4fun 03-09-2018 06:57 PM

Quote:

Originally Posted by MadMan (Post 3196777)
Neat. I'd like to see what it does.

Quote:

Originally Posted by dieseljeep (Post 3196896)
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. :scratch2:

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 .

Kevin Kuehn 03-11-2018 04:39 PM

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.

init4fun 03-12-2018 06:38 PM

Quote:

Originally Posted by Kevin Kuehn (Post 3197138)
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 ...

dieseljeep 03-20-2018 10:13 AM

Quote:

Originally Posted by init4fun (Post 3197167)
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.

radioal 03-22-2018 01:35 PM

Quote:

Originally Posted by dieseljeep (Post 3197349)
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.

Sent from my LG-SP200 using Tapatalk


All times are GMT -5. The time now is 07:13 AM.

Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
ęCopyright 2012 VideoKarma.org, All rights reserved.