Old Oscilloscopes - Videokarma.org TV - Video

Adam · #1 03-11-2006, 09:25 PM

Anyone here like old oscilloscopes? I was wandering through this used electronic parts store's yard today and found a really old one sitting in the rain, and I had to rescue it. "Dumont Cathode-Ray Oscillograph" model 274, it uses the 5BP1-A crt. It looks at least 1940s. It uses two #80 tubes, I don't know when they stopped using those old tube designations, but I thought it was sometime in the 30s. Despite being out in the rain it is actually clean inside, but it uses some capacitors for which locating replacements would be nearly impossible: 5mfd at 1500volts and such. I don't really need another working one anyway, I might just put this ontop of a TV and look at it.

Celt · #2 03-11-2006, 09:55 PM

I really hate to do this...but...

Dynacophil · #3 03-12-2006, 04:11 AM

Quote:

Originally Posted by Adam

Anyone here like old oscilloscopes? it.

Hi
I Like my Oszi, but i do not no anything about ....

looking for Manual for this mine

Helge

nasadowsk · #4 03-12-2006, 02:32 PM

Heh
I like the old Tek 500 series stuff. It...just...works...

Would love a good scope cart for my 545A. And get a 580 (they NEED a scopecart!) or a 547...

bgadow · #5 03-12-2006, 08:13 PM

I had a DuMont that looked like it came off the ark; sold it for about $3 at the ETF convention last year. I got rid of most of my old scopes as they were just taking up space-right now I have an EICO, I think there is still a Bell+Howell school scope somewhere hiding, plus a little RCA from the early 70s that I keep on the bench. I'm no good with them-yet. I do have one other, which I need to keep. It's an RCA, pretty early, which was resprayed with silver paint. Under the paint you can read the old lettering-"NBC TV, Washington". Like all the others, it works at least to the point of putting light on the screen.

blue_lateral · #6 03-12-2006, 09:01 PM

I have a Tek 535, an early production one from about 1955. I had intended to restore it slowly as I had time. It worked when I got it, after a little recapping, it works perfectly. Since it got here, I havent used anything else. The "modern" scopes are gathering dust now...

John

3Guncolor · #7 03-12-2006, 11:13 PM

I have two 535's one early and one late production. The late one is operational but the early one had one of the wafer switches burn up. It does work but the trigger is now fixed. I got the early one when I was in high school in 1977 so I will keep it maybe some day I will find a parts unit. They are handy in winter to use as space heaters. Tube scopes can be handy when working on high voltage devices, the input stage tubes can take a boo boo better soild state scopes. I've had to repair a few front ends on soild state scopes so I have a few small tube scopes to use if I'm working on something that might spike my good scopes.
Steve

larschr · #8 03-13-2006, 03:56 AM

I have this Philips PM3230 tube scope. I got two of them from a local school, none of them working properly. One of them looked very good, and the other was dirty and worn. I got the clean one to work and kept some parts (tubes) from the other one. It har 7 tubes plus the true-dualbeam CRT. It works perfectly and looks pretty good too - a nice piece of equipment. I have not replaced any components yet. I tested some random caps, and they tested good, so i left them in.

mhardy6647 · #9 03-13-2006, 08:55 AM

I have a Tek 545(A?) -- I can't find a picture of it at the moment :-(

Sandy G · #10 03-13-2006, 09:35 AM

I've got an RCA Cathode Ray Oscillograph (!) from 1935-uses a 1" metal CRT, & a Waterman Pocketscope from right after the war. Neither works, they light up, but that's about it..Would like to get 'em both geein' & hawin' again...-Sandy G.

markthefixer · #11 03-13-2006, 12:49 PM

I haven't kept anything that didn't have a triggered sweep, having worked with MANY scopes that didn't. I'm STILL sick of Lissajous patterns, even though they can be extremely accurate on matching frequency and phase.

I have had intimate introductions to the HV on some of those older scopes.....

That said, even though the trace isn't as sharp as some of the older scopes, the Tek 464,466 storage scope traces are sharp, and the 465's and 475's have a passable trace.I also have had the HP 17xx scopes, keeping a 1726 currently.

markdi · #12 03-13-2006, 03:16 PM

I have a complete but not working tek 535

it is getting a little rusty in my carport

I should rescue it - I think I hear it calling to me.

Nick_the_'Nole · #13 03-13-2006, 04:55 PM

I've got an RCA WO-56 from around '52 or '53, not working. I'll get around to trying to fix it one of these days, but I have a suspicion the power tranny might be bad...

old_tv_nut · #14 03-13-2006, 05:05 PM

Quote:

Originally Posted by markthefixer

I have had intimate introductions to the HV on some of those older scopes.....

IIRC, they were built the opposite of a TV, with the faceplate at ground and the cathode floating at (minus) high voltage...

markthefixer · #15 03-13-2006, 07:52 PM

Quote:

Originally Posted by old_tv_nut

IIRC, they were built the opposite of a TV, with the faceplate at ground and the cathode floating at (minus) high voltage...

Well the filament and the cathode are usually at or near the same potential so there is always the problem of moving a few watts way "uphill" to get that filament to glow.

Did some 1" electrostatic deflection crt work for some military apps, and it was preferred that whatever voltages were used, that the electrostatic deflection plates were closest to ground potential, thus like tek we had -2kv to the cathode, and an isolated filament that we had to pump a couple of watts up to -2kv to light the filament, then we had the anode at +5 kv (tek 4xx is +15kv??).

That's when I started to like magnetic deflection in crt's.

I don't remember how the old eico's etc that I worked with were set up.

I've been "bit" by scopes, lasers and whatnot... (over 30+ years) the most memorable (to others, I don't remember much) was the laser start circuit that arced through a supposed insulator.....