New find!

[martin martin]

Since we are on the subject of CRTs...  I was asked to pickup all kinds of vintage items from an "Estate Giveaway"

Here's the first one!  More on the way, Heathkit VTVMs too..

[Richard Nicewonger]

When RCA was in its heyday, they promoted their "RCA Institutes” correspondence courses in electronics. As part of the course in

TV/radio servicing, the students had to assemble their own test gear. This was one of those items. It is actually a rebranded Eico

model 430 oscilloscope from the late ‘60s. I know this since I have the model 435 which appears similar but has better bandwidth.

I have always liked the looks of this series of test equipment that Eico made during this period compared to their earlier designs.

They are simple to use and relatively easy to fix since they don’t have sophisticated features like triggered/delayed sweep. It looks

like you’ve scored a nice one. Good luck and enjoy!

Rich

On Feb 22, 2022, at 9:45 AM, martin martin <mcve...@gmail.com> wrote:

Since we are on the subject of CRTs...  I was asked to pickup all kinds of vintage items from an "Estate Giveaway"

Here's the first one!  More on the way, Heathkit VTVMs too..

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<RCA.jpg>

[gregebert]

What's even more interesting is that a lot of these old dinosaurs still work. A friend at work gave me a US Navy scope (USM-117) from the early 1960's, and at first it was having some problems generating high-enough anode voltage for the CRT, but letting it run a few hours apparently coaxed the capacitors into working again. The other neat thing about this scope is that the only vacuum tube is the CRT; everything else is transistors which was quite a feat for 1963.

Many of our beloved nixies and CRTs are approaching, and even exceeding, 60 years old and I am in awe of the fact the vacuum seals apparently are still holding.

[Robert G. Schaffrath]

I have an old US Navy scope but I have no idea of the USM model. I bought it at a hamfest back in the mid-1970's when I was a kid for $5. It was made by Dumont no less! The thing weighs a ton. The 5JP1 tube was bad and it needed to be recapped. My maternal grandfather gifted me a new tube that he got at Liberty Electronics in New York City. The capacitors I had to special order at Lafayette Radio and they came in in drips and drabs (thankfully - I did not have a lot of money). I also managed to blow the 991 neon regulator bulb and a good friend of my fathers who worked as a transmitter technician for WVIT-TV in Hartford sent me a replacement. I also managed to track down a user manual at the time as it turned out that Fairchild had bought out what remained of Dumont and had their intellectual property. The original Dumont manual has a Fairchild cover stapled to it. Funny how one could get information and parts without the Internet back then.

I still have it though I have not turned it on in probably 20 years. I would have to hook it up to my variac and slowly power it up again to allow the capacitors to reform. I have not had much use for a scope these days and if I did, I would get a device that interfaced to my PC.

[martin martin]

Part 2!  Bell & Howell (Heathkit 2 digit DMM), nice analog meter and two odd test meters.  Check out the 30 year old Eveready !  Still has less than 1.5 V

The Heath works great, just needs a cleaning and possible cal.

[John Rehwinkel]

What's even more interesting is that a lot of these old dinosaurs still work. A friend at work gave me a US Navy scope (USM-117) from the early 1960's, and at first it was having some problems generating high-enough anode voltage for the CRT, but letting it run a few hours apparently coaxed the capacitors into working again. The other neat thing about this scope is that the only vacuum tube is the CRT; everything else is transistors which was quite a feat for 1963.

I picked up this USM-117 at a hamfest for a few bucks in "you fix" state.  It turned out to be pretty dirty and beat up, a few bad transistors, and the base had come off the CRT.  I had never reattached a CRT base before, but I figured I had little to lose.  I ended up curing the base cement in the kitchen oven.  It worked, too!

- John

[Toby Thain]

Beautiful! What are you using to generate this image?

Thanks
--Toby


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[gregebert]

I dont see a connection to the Z-axis (or did you use connections from the back-side of the case ?) so I'm surprised to see such a crisp text display. I was planning to turn my USM-117 into a scope-clock, but I found a decent kit  online last year. Even though I have an HP digital scope, I still like bringing out this oldie for every now and then for bench work.

[John Rehwinkel]

Beautiful! What are you using to generate this image? 

I'm using an AdaFruit ItsyBitsy M4 Express with its two analog outputs to drive the X and Y inputs. The text is being generated using the old Hershey vector font.

I dont see a connection to the Z-axis (or did you use connections from the back-side of the case ?) so I'm surprised to see such a crisp text display. I was planning to turn my USM-117 into a scope-clock, but I found a decent kit  online last year. Even though I have an HP digital scope, I still like bringing out this oldie for every now and then for bench work.

 For visible segments, I draw slowly, for others, I move quickly, so I'm not using the Z input.  

- John

[Toby Thain]

Ah nice, I am working on an X/Y/Z driver that could be used for CRT
clock purposes. Rather than direct X/Y drive, it uses integrators for
analog lines.

Some of the specs are here:

https://github.com/larsbrinkhoff/vector-terminal/issues/4#issuecomment-1065940052


And some pics from yesterday:
https://www.flickr.com/photos/qu1j0t3/albums/72177720297457916

It does text, but this isn't shown here.

If anyone is interested in a PCB, contact me privately I guess!

--Toby


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[Bill Notfaded]

Martin you always come up with some cool stuff brother!  I know you're a fan of nixie counters too... me too!  I like to keep them in their original form not tear them apart for the tubes.  Nothing like a still working nixie frequency counter right!

Bill

[Bill Notfaded]

I pre-ordered a chromagnon:. https://lzxindustries.net/products/chromagnon

I have a vector scope I'm going to use it with and am thinking about getting a white laser to interface with it.  Here's the vector scope:

[Bill Notfaded]

This is what I'm going for:

https://youtu.be/eLrofQRFQ6k

Bill

[Bill Notfaded]

This is what this is all about:

https://youtu.be/eLrofQRFQ6k

Bill

[Bill Notfaded]

This applies today:

https://youtu.be/uWveRkuDGqw