Analog oscilloscope, swapping the CRT

[Cobalt60]

I have an old Telequipment analog oscilloscope that works perfectly, aside from a sketchy probe. It has modest specifications, but is good for anything I plan on needing it for anytime soon. The main thing I dont like about this scope is that it is a rackmount, very clumsy and takes up a lot of space. Approximately 33% of the case is completely emprty. I would like to convert it into a benchtop unit.

My question is, can I take all of the circuitry out, and attach it to a different CRT? And if that even worked, would it still be an accurate scope?

I could, for example, convert an old TV into an accurate bench scope. But the CRT on the scope now is only like 4", so am wondering how it would work on something like a 9" or larger CRT. Another idea, although some may not like it, is to convert an old Mac Classic I have to an oscope. It is nice because it is small, has a handle for carrying, I believe just enough room to fit the oscope PCB and all the dials, and has a (guessing) 9" B&W CRT. Or another idea would be to slightly mod the CRT from my Apple //e to accept an input from the oscope PCB.

Thanks for any advice.

-Chris P

 

[Nigel Goodwin]

Oscilloscope tubes are completely different from other types, you can't swap tube types - it would even be difficult to swap different oscilloscope tubes over, as their specs could be very different.

 

[Cobalt60]

Ahh thats too bad. Looks like Ill have to either just buy a bench scope, or maybe buy a non working bench scope and swap my parts into the bench case.

 

[Reloadron]

Look, you have a working scope. So it is a rack mount which makes it wide. There are poor starving techies in this forum who would love to have any scope. Be happy, life is good and if something works, don't screw with it. Leave well enough alone. Forget swapping and moving parts. Be happy!

Ron

 

[Cobalt60]

Meh, I got it for $20. Being a rack mount also makes it heavy, and the corners of the metal are hard and hurt when i bump into them. I need a scope to be permanently setup, the only way I could do that with this one is to get a stand/rack/whatever. But yeah Id really like a scope for, you know, my bench-top. Perhaps I will leave this one unscrewed with, but one way or another I need a bench scope. By the way, I am in Newport News Virginia if anyone has one for me, or wants the one I have.

 

[Reloadron]

I don't want the one you have. How much did you want to spend for a scope? I have one of these lying around that I got maybe 6 months ago from another forum member. It is a good dual channel scope with plenty of features. They seem to be selling on Ebay for about $300 if something like that is in your range including shipping. That or feel free to drive to Cleveland and make an offer. However, I would think you could find plenty of really good used scopes in your area for a good price. Actually I have yet to plug the thing in and try it out. I already have several good scopes I use. I do not have the service manual with it.

Ron

 

[Cobalt60]

Here is the bench version of the scope I already have:
**broken link removed**

So if I found like a broken one I could swap my parts over to that bench case.

Well, since I was trying to convert random CRTs I have lying around into oscilloscopes, I went into this post trying to spend approximately $0. But since that doesnt appear to be an option, Id really like to get one for under $100. Indeed I dont think I will have much issue getting one. I was originally afraid no one would want the one I currently have if I did get a new one. But I think it is true that some people would really appreciate having even this clunky scope, as I did when I first got it.

 

[Reloadron]

The problem you will have is the parts configuration between the rack mount and the bench chassis. Personally I just don't see it as a viable way to go. For $75 to $100 you should be able to find a pretty good analog scope with maybe a 20 MHz bandwidth in your area or even better.

Just My Take
Ron

 

[JimB]

Here is the bench version of the scope I already have:
**broken link removed**

That scope dates from the 1960s, it is pushing 50 years old!
Not only that, it was a poor scope when it was new.
$75 for that one on e-bay? The guy is having a laugh.

Look for a Tektronix or Hewlet Packard scope, a much better bet than a 1960s Telequipment.

Deviating somewhat of topic...
What does intrigue me, is why would a mediocre UK make scope end up in the USA?
Also, the guy selling it is in Alamagordo NM. Could it be a left over from some atomic project?

JimB

 

[Cobalt60]

What does intrigue me, is why would a mediocre UK make scope end up in the USA?

Not sure but I got mine in the US, in Connecticut. But yeah mine was $20 working perfectly with a probe, that guy thinks its worth more than it is.

Look for a Tektronix or Hewlet Packard scope, a much better bet than a 1960s Telequipment.

I thought Tektronix was just the UK version of Telequipment?

Anyway, I dont think it will be too hard to find a scope, but so far theres 0 on Craigslist and maybe 2 within 45 minutes of me on eBay. Last time I went pawn shop hopping I also found 0 at like 8 shops. But again, I do think I can eventually find a nice one locally.

 

[Cobalt60]

That scope dates from the 1960s, it is pushing 50 years old!

Just wanted to add; it doesnt bother me thats its so old. As long as it works well. My bench power supply is a Power Designs 3650, from the 60s. It can go to 36V and 5A, whereas most comparable modern supplies only do 30V and 3A. It also has better ripple rating than a lot of the newer ones. And, I think it is incredibly awesome that it has in a built in variable transformer. For all it is, and with its classy styling and all metal knobs, I think it is worth a hell of a lot more than the $75 I paid for it.