Beauty of old electrical and measuring things, etc.

[Opera]

I'm a thousand miles away for the summer. Several other items. Posted to bookmark the thread.

 

[jedishrfu]

Wow that's quite collectible. So you said it had a CRT and not nixie tube digits.

Is it an HP 9100?

https://history-computer.com/hewlett-packard-9100a-guide/

 

[dlgoff]

Wow that's quite collectible. So you said it had a CRT and not nixie tube digits.

Is it an HP 9100?

https://history-computer.com/hewlett-packard-9100a-guide/

I'm not sure what part of this thread you are referring to. Can you post the page you are asking about?
@berkeman
Since you liked the post, maybe you know?

 

[berkeman]

I'm not sure what part of this thread you are referring to. Can you post the page you are asking about?

I think they are referring to this post by new member @Opera:

I have the first HP desk calculator with a CRT and delay line for memory. It has this interesting feature; the keyboard mechanically locks up while it is doing a calculation. Odd that this was easier done mechanically than with electronics. I'm away so will picture some stuff later.

 

[dlgoff]

I think they are referring to this post by new member @Opera:

Oh. Now I understand. Forget the request in my previous post.

Thank you.

 

[dlgoff]

When you get old, you get forgetful, so I don't remember if I've posted this old Model 83 Fluke Meter:

 

[berkeman]

Who you calling old? I have a couple of those in our lab...

 

[berkeman]

BTW, have you ever tried to replace the fuse for the uA/mA current measurement input? What a weird size fuse!

 

[dlgoff]

BTW, have you ever tried to replace the fuse for the uA/mA current measurement input? What a weird size fuse!

It was a long time ago, but I do recall. I'm not wanting to open it up, but didn't it have a very small diameter glass fuse? Do you remember when those meters were introduced?

I'd never call you old as I'm the old one here.

 

[berkeman]

IIRC, the fuse was physically bigger than the standard sizes that we carried in labstock. I think I even checked the local electronics stores, with no joy. I have at least a couple of those meters with blown mA circuit fuses and notes on them to let the operators know.

 

[dlgoff]

IIRC, the fuse was bigger than the standard sizes that we carried in labstock.

Now you've got me curious. I will have to open it a check it out. From some google searching, it looks like it came out in the 1980's.

 

[dlgoff]

IIRC, the fuse was physically bigger than the standard sizes

Yes. You're right. They're really large:

 

[DaveE]

Yes. You're right. They're really large:
View attachment 304279

We used a bunch of those fuses (KTK, KLK) in our Ion Lasers. They're rated to interrupt HV DC and/or high interrupting capacity, hence big and expensive. Full of glass/sand around the filament.

 

[dlgoff]

our Ion Lasers

I'd like to see one of those. :)

 

[Baluncore]

I'd like to see one of those. :)

Eye safety precludes that.

 

[Oldman too]

This might qualify for the thread, wife picked it up at a yard sale along with a nice arrowhead collection for $5.00. The plastic battery case is cracked but it works great, ordered replacement cases from ebay, just waiting on them to arrive before using it. It's a model 63TR, circa 1974.

 

[dlgoff]

This might qualify for the thread, wife picked it up at a yard sale along with a nice arrowhead collection for $5.00. The plastic battery case is cracked but it works great, ordered replacement cases from ebay, just waiting on them to arrive before using it. It's a model 63TR, circa 1974.
View attachment 304497
View attachment 304498View attachment 304499

My parents did a lot of hunting for old coins with White's metal detectors.

 

[Oldman too]

My parents did a lot of hunting for old coins with White's metal detectors.

That's one of my wife's obsessions, along with gold, fossils, rock hunting etc. While searching for battery parts, I was dismayed to learn that Whites recently went out of business, then I found out Garret had taken over the Whites label. I still had to go to ebay to find the parts though.

 

[DaveE]

Cleaning up a bit at my mother's house, I found some old electronic parts my father saved. He was an EE (too) from 1950's - 1970's. This one caught my eye. GE 2N107, packaged in it's own tube with a datasheet printed on vellum.

So, knowing I had no desire to actually use it, I cut it open to see the guts.

That transistor die is about 3mm x 3mm. If you wanted to make a modern uP with about 20 billion transistors, it would cover about 1/2 mile².

It is beautiful to me, in it's appropriate context. Back when a single transistor was high tech.

 

[hutchphd]

Point contact. Wow that is neat. Thanks

 

[Joseph M. Zias]

The 2N107/2N170 pair were the hobbyist transistors of the late 50's and early 60's. In the 70's I worked for a company that was still using the 2N1370 series germanium transistors. Some of the old circuits with germanium won't work with silicon.

 

[jedishrfu]

And as The Antique Roadshow appraiser would say:

Wow, now if only that was an intact transistor, it would be worth $XXX,XXX dollars at auction and maybe even as high as $X,XXX,XXX but sadly now its worth $X-$XX

 

[Borg]

Yeah, it was sad to see that an antique complete with papers, was dissected.

 

[jedishrfu]

I checked and you're good they are in the range of $X to $XX across ebay and etsy, There is one on display at the computer history museum:

https://www.computerhistory.org/collections/catalog/102718890

 

[jedishrfu]

Yeah, it seems only Robots and the @Borg can appreciate the sadness of having one of our single celled ancestors dissected in the name of curiosity.

 

[dlgoff]

Here are a couple of old beauties. Too bad they don't work:

 

[DennisN]

@dlgoff :
"r/hr"... I had to google for it. "Roentgen/hour" I suppose?
And if so, I guess they are some sort of radiation detectors/radiation measuring devices?

 

[dlgoff]

Roentgen/hour

Yes.

 

[jedishrfu]

Are they old enough for the Troy Incident?

https://churchtree.tripod.com/troyincident.html

 

[jedishrfu]

Are the batteries dead, or is there something about the detectors reaching the end of life?

 

[dlgoff]

Are the batteries dead, or is there something about the detectors reaching the end of life?

I put in a new battery and the one on the left one looks okay doing a "circuit check". So must have been a dead battery. The one on the right still doesn't work with a new battery. :(

 

[dlgoff]

Are the batteries dead, or is there something about the detectors reaching the end of life?

This old Ludlum (counts/minute) works good though:

 

[Tom.G]

Here are a couple of old beauties. Too bad they don't work:

Since they are "identical" they should be a breeze to troubleshoot, especially if you have an oscilloscope available.

If that's not your thing, post schematics, photos, and whatever voltage readings you can get. I suspect the combined grey-matter mass here would solve the problem shortly.

 

[dlgoff]

Since they are "identical" they should be a breeze to troubleshoot, especially if you have an oscilloscope available.

If that's not your thing, post schematics, photos, and whatever voltage readings you can get. I suspect the combined grey-matter mass here would solve the problem shortly.

I have an old Heathkit scope. If you look back through this thread, you'll see that I've restored many old beauties. But in this case, I just don't want to take the time and effort to restore that old counter. Thanks for the offer though.

 

[DaveE]

I just don't want to take the time and effort to restore that old counter.

Yup. My experience repairing old test equipment goes like this:
You can either diagnose and fix it quickly, like 1 hour, or it's nearly impossible and will take much more time than it's worth.

I also like the "buy two broken ones, make one that works and throw out the rest" approach*. Swapping parts/modules often doesn't require a lot of knowledge or effort.

The sad, painful, truth is that if you just want to make a measurement, you can probably buy a new version from China on eBay for less effort, time, and money than repairing the old stuff. But then part of your DIY EE soul will die with each purchase.

* Full disclosure: I'm actually not that good at the "throwing out the junk" part of this.