Random tube scope screenshot - Page 1
Forum section: electronics / general

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: February 12, 2023, 01:47:31 am
content: No reason, I was just playing around with my NTSC test signal generator and my Amiga monitor when I got the urge to see the NTSC colorburst.The upper waveform is NTSC video with a highlighted colorburst, and the lower trace is the expanded view.That's the B intensified by A alternate mode, and a big old 10 turn pot sets the intensified area.I just think it's cool, and it does help heat the place a bit as winter winds down...

author: PwrElectronics
author_rank: Regular Contributor
timestamp: February 12, 2023, 08:11:50 pm
content: NiceI also have a 547 and a 1A4 in my collection. 547 not working and went to cold storage though. 1A4 was working last I know but has broken plastic coupler things on some of the pot shafts inside.

author: David Hess
author_rank: Super Contributor
timestamp: February 13, 2023, 12:57:00 am
content: The 547 was the last "fast" oscilloscope from Tektronix which did not use scan expansion, so it produces a sharper display than later instruments. TV production businesses kept them in service long after they were obsolete because of this.

author: basinstreetdesign
author_rank: Frequent Contributor
timestamp: February 13, 2023, 04:28:39 am
content: I have the same scope and a calibrated NTSC test-signal generator as well (Leitch CTG-210). I sometimes make the same display just for old times sake. But I do not have the 1A4 and wish I did.

author: vk6zgo
author_rank: Super Contributor
timestamp: February 13, 2023, 07:41:26 am
content: Quote from: Alex Eisenhut on February 12, 2023, 01:47:31 amThat is the sort of display that early DSOs tried to reproduce, failing miserably in the attempt.A lot of previously "digital friendly" Techs & EEs in the TV Industry were put off by their disappointing performance on standard video signals, compared to even the earlier generations of analog instruments, such as the 547.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: February 14, 2023, 03:18:22 am
content: The only thing missing from the 547 is a video trigger. Just a basic "TV line H or V" like on cheap service scopes would be nice.I've been meaning to slap a LM1881 and some other junk on a piece of perfboard for about 10 years now. Maybe this year...

author: vk6zgo
author_rank: Super Contributor
timestamp: February 14, 2023, 04:53:40 am
content: Quote from: Alex Eisenhut on February 14, 2023, 03:18:22 amWe triggered 545Bs on both horizontal & vertical syncs for years without needing "no Steenkin' video trigger".It's just a matter of thinking where to set your trigger point.The only time I've needed an external trigger box, with either 500 or 7000 series Tek CROs was if I was looking at Vertical Interval Test Signals, & even with those, you can do without, with a bit of "fiddling".A sneaky trick for looking at field rate signals is just to trigger the 'scope off the so-called "Line" (50/60Hz Mains) trigger facility.It isn't perfect, as there is some very long term drift compared to field rate, but short term, it is unnoticeable.

author: tautech
author_rank: Super Contributor
timestamp: February 14, 2023, 07:17:19 am
content: We have similar from the STB-3 that is very difficult to trigger on with a normal edge trigger but you can get it sorta stable with some holdoff and some fiddling but when zone triggers got added to scopes it became easy to get a good rock solid capture.Here I use an edge and 2 zone triggers.

author: TomKatt
author_rank: Frequent Contributor
timestamp: February 14, 2023, 11:38:35 am
content: Years ago I picked up an oldWaterman 'Pocket Scope'made in the late 1940's for cheap at a ham market. Came with a beautiful purple velvet lined hardwood box case. Considering the size of tube gear, I guess 'Pocket' somewhat applies, although it's nowhere near what you would consider pocket today. It has a very simple 4 tube (+rect & crt) design with no triggering or calibrated timebase. And yet looking through themanual, it can be used very cleverly and I'm sure was a handy mobile service tool for radio and the first days of television. Almost like a cheap DMM, it's great for just checking the presence of signals and seeing if they appear visually correct - which can actually get you quite a ways towards diagnosis and repair.I'm inclined to believe it has the original tubes, and although it 'worked' when I obtained it, the old electrolytic caps were completely gone. Not to mention replacing the old dried up 2 prong line cord (outlets didn't have ground pins back then). An easy fix, and now it serves as a nice scope clock and other random vector project displays (even has Z input capability).Edit - re the OP... The 547 with the 4 channel 1A4 vertical (4 channels!) is pretty cool because you can view multiple timebases on 2 channels, almost like a true dual beam scope. Nice!

author: vk6zgo
author_rank: Super Contributor
timestamp: February 14, 2023, 11:40:22 pm
content: Quote from: TomKatt on February 14, 2023, 11:38:35 amThe only thing I've seen from Waterman was a old (1940s/50s) slide projector, years ago.

author: David Hess
author_rank: Super Contributor
timestamp: February 15, 2023, 12:02:07 am
content: Quote from: TomKatt on February 14, 2023, 11:38:35 amThe 4-bay 7000 mainframe oscilloscopes preserved that capability with a mode where one timebase is assigned to each vertical plug-in.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: February 15, 2023, 04:11:10 am
content: Quote from: David Hess on February 15, 2023, 12:02:07 amThe 1A4 has something similar, there's a switch behind the plugin, it locks channels 1 and 2 to time base A of a 547 and 3 and 4 go to B.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: February 15, 2023, 06:07:08 pm
content: Quote from: basinstreetdesign on February 13, 2023, 04:28:39 amHere's the junior edition:https://www.ebay.ca/itm/175614472627A bit dinged up and missing Nuvistors... but ...