On 2017/11/10 12:46 PM, John-Del wrote:
On Friday, November 10, 2017 at 11:04:53 AM UTC-5, Stephen Wolstenholme wrote:
On Fri, 10 Nov 2017 07:44:42 -0800 (PST), wrote:

On Friday, 10 November 2017 15:38:55 UTC, John-Del wrote:
On Thursday, November 9, 2017 at 5:58:53 PM UTC-5, Michael Terrell wrote:
bitrex wrote:

Not exactly a sophisticated piece of test equipment, but lets you eject
bad metal enclosure tubes early:

https://www.dropbox.com/s/m5b4ogl4pqn8tu1/IMG_20171109_110954264.jpg?dl=0

a red dot, useful

(all the metal tubes in the 1935 table radio passed)


A common as dirt filament tester. They were common as dirt, and sold
for about $3 in the early '60s. They hyped as real tube testers.

Not sure how they were hyped, but we used them all the time in the 70s to locate an open tube(s) in series sets. We kept one in our road tube caddy; it even used the same "cheater" cord as the TV did. You'd be surprised how many low end TVs used a series string back then and how often a dead TV was an open filament.

I thought almost all valve tvs used series heaters. Mine doesn't but it's an unusual design, Ekco tmb272.


I was a TV engineer for nearly ten years. I never saw a valve TV that
didn't use serial heaters.

Steve

--
http://www.npsnn.com

What country? In the U.S., there were half a dozen large manufactures and they all used power transformers in their console and most table models, leaving some off brand consoles, table models and most portables as series string. I would say at least 80 percent of TVs I worked on at the end of the tube era were equipped with parallel filament circuits.

RCA, Zenith, Motorola, Sylvania, Philco, Admiral etc. all used power transformers. RCA, Zenith and others continued this practice even when they switched to solid state.


1970s several 12" & 16" GE portable tube TVs used series tube wiring. I
service these TVs as they were used in the first coin operated video
game - Computer Space by Nutting Assoc. There was no line isolating
transformer in the TV, Nutting added one in the cabinet to allow the TV
to be safely used as a B&W monitor.

John :-#)#

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