Beauty of old electrical and measuring things, etc.

[DaveE]

So, what are the actual numbers written on the chip, and how do you know it is a TTL 7490 ?

There's lots of cross reference tables on the web, like this one. ICs in HP instruments rarely have JEDEC labels. I don't have a clue about the lot/date code though.

 

[Baluncore]

I don't have a clue about the lot/date code though.

Why will you not give me all the numbers ?

 

[dlgoff]

So, what are the actual numbers written on the chip, and how do you know it is a TTL 7490 ?

I zoomed in on the image and it looks like it's a TI 1820-0055:

According to this site it's equivalent to the 7490 decade counter.

 

[DaveE]

Why will you not give me all the numbers ?

Sorry I don't understand. If you're asking why I won't give you the lot/date code decoding for TI semiconductor DIP markings from 50 years ago, it's because I don't know or care.

I never really did care much about date codes, except in unusual circumstances, and even then it was mostly about matching or making sure you're not doing a parameter characterization on a bunch of nearly identical parts. If I needed to know that stuff I would have already been talking to the applications engineers about it anyway.

Still if I had to bet I'd say the 52nd week of 1969, as you suggested.

 

[dlgoff]

...it's because I don't know or care.

Now I'm wondering why you posted this?

 

[DaveE]

C

Now I'm wondering why you posted this?

Caring about old equipment isn't the same thing as caring about decoding IC lot/date codes from 50 years ago.

 

[dlgoff]

...it's because I don't know or care.

Caring about old equipment isn't the same thing as caring about decoding IC lot/date codes from 50 years ago.

Well, you did post it in my Beauty thread. You don't think date codes goes into my restorations?

 

[DaveE]

Well, you did post it in my Beauty thread. You don't think date codes goes into my restorations?

I don't know anything about your restorations, but I think it's cool if you care about them. Nevertheless, we all don't, nor should we, care about exactly the same stuff.

Just let me know if you don't want me to post here anymore, I don't wish to interfere with your thread ownership concerns.

 

[dlgoff]

Just let me know if you don't want me to post here anymore, I don't wish to interfere with your thread ownership concerns.

No problem with your post, as I gave you a like for it's beauty.

 

[berkeman]

Just let me know if you don't want me to post here anymore, I don't wish to interfere with your thread ownership concerns.

It's more like a loving commune, not so much ownership.

 

[dlgoff]

I've been restoring this old Universal Radio. I've replaced all the tubes (most are metal tubes). One of the coolest glass tubes is the 6U5/6G5 magic eye tuning tube.

@berkeman mentioned me in this post when discussing coils. Lots of coils here.

I think all I need to do now to get it to work is replace all the electrolytic capacitors.

 

[berkeman]

Wow, what year is that from?

 

[dlgoff]

Wow, what year is that from?

Well I'm not too sure but I think it's from the 1920s. This was in an old warehouse owned by a lady who I asked if she was interested in selling it; that was sometime in the 1970s. She had no interest in selling it and said just take it.

 

[anorlunda]

It's weeping in distress. Help me.

I'm curious. What is your general procedure for these restorations?

• Disassemble everything?
• Restore cosmetically as well as functionally? Internally too?
• If you must replace something, like a segment of wire or an electrolytic capacitor, do you use modern parts and materials?
• Lots of questions.

A short tutorial, "How to go about an electrical restoration." would be educational and entertaining.

Edit: An Insights article would be perfect.

 

[dlgoff]

It's weeping in distress. Help me.
View attachment 279531
I'm curious. What is your general procedure for these restorations?

• Disassemble everything?
• Restore cosmetically as well as functionally? Internally too?
• If you must replace something, like a segment of wire or an electrolytic capacitor, do you use modern parts and materials?
• Lots of questions.

A short tutorial, "How to go about an electrical restoration." would be educational and entertaining.

Edit: An Insights article would be perfect.

In this case,

• Restore cosmetically as well as functionally? Internally too?

I'll have to write up something as a tutorial. But I'm a little underwater with time right now. Soon heading for my second Moderna COVID-19 shot.

 

[dlgoff]

It's weeping in distress. Help me.

Indeed. I never noticed this. The whole radio needed help.

 

[dlgoff]

One of the most difficult parts of this restore was keeping all the cloth covered wire from shorting together. I dissolved some silicon sealant in alcohol and painted all of them before powering up this old radio.

 

[gmax137]

I dissolved some silicon sealant in alcohol and painted all of them before powering up this old radio.

That right there is a cool tip.

 

[Klystron]

Very interesting radio chassis. The tubes (valves in UK?) appear familiar but the jumble of circuit components makes one think the design engineer ignored placement issues such as inter-electrode and distributed impedance. The receiver probably frequency drifts as the tubes warm up; hence, the vernier dial controls?

 

[anorlunda]

The tubes (valves in UK?) appear familiar but the jumble of circuit components makes one think the design engineer ignored placement issues such as inter-electrode and distributed impedance.

What design engineer? My grandfather provided for his family during the great depression by making radios out of Quaker oatmeal containers. That makes me believe that in those days, many sources could manufacture electrical things without the services of a real engineer.

 

[Averagesupernova]

As far as lead placement and such goes, the AM broadcast band is very forgiving. We're not talking about VHF or even HF here. I used to work with a guy who said jokingly that anything below 100 MHz is DC.

 

[dlgoff]

Edit: An Insights article would be perfect.

Good idea. Let me think about it. In this thread, I have, I think, gave some info about how the restores were done. Mainly, making them look beautiful and working is part of the beauty.

 

[dlgoff]

As far as lead placement and such goes, the AM broadcast band is very forgiving. We're not talking about VHF or even HF here. I used to work with a guy who said jokingly that anything below 100 MHz is DC.

There are three bands indicated: Broadcast, Amateur, and Shortwave (5.5meters to 55meters) labled: FOREIGN, PHONE, and SHIPS.

 

[DennisN]

"Beauty of old electrical and measuring things, etc."
I recently won a real beauty on an online auction. I will take some photos and post later here.

 

[DennisN]

I recently won a real beauty on an online auction. I will take some photos and post later here.

Here is my recently bought Yashica Electro 35 rangefinder camera (from late 1960s to early 1970s).
Quote from Wikipedia: "It was the first electronically controlled camera."

I won it recently at an online auction for about $66. It is in marvellous condition (near mint).

I bought it for nostalgic reasons; my father had one and it was one of the very first cameras I used as a child.
It was amazing to get a hold of one, since I started to remember all the controls and even the look in the viewfinder. I even recognized the smell of it, actually!

Here are some photos:

Front:

Back (opened):

The "atomic" logo:

Top:
(from left to right: film winder, hot shoe for flash, exposure indicators (I think) (slow/over), film ISO setting, shutter button, frame winder, frame number window)

Lens closeup:
(the red "thingy" on the lens is a timer for taken timed shots. You pull it to a certain distance and then press the shutter button, and when the timer "thingy" reaches the default position, a photo is taken)

It may very well work too, and I am thinking of trying to use it some day.

 

[jedishrfu]

Nice camera. Let's hope it works and that you can find some film to fit it.

I like the atomic logo too.

 

[Janus]

In the same vein, here's my "used to be my parents" Bell and Howell movie camera and case, from the 1950's

 

[jedishrfu]

My Dad had something like that too and the projector to go with it. My how things have absolutely changed.

 

[berkeman]

My Dad had something like that too and the projector to go with it. My how things have absolutely changed.

Yeah, mine too. Remember how every once in a while the film would break during home movie night? Dad would say, "We will now take a quick break while I splice this back together...". I guess we still have something similar -- "Dad, our WiFi just went down!"

 

[Janus]

Yeah, mine too. Remember how every once in a while the film would break during home movie night? Dad would say, "We will now take a quick break while I splice this back together...". I guess we still have something similar -- "Dad, our WiFi just went down!"

We had the projector too, though I don't know what came of it. Did anyone else's folks have the Light Bar for the camera? It Looked like this:
https://d3h6k4kfl8m9p0.cloudfront.net/stories/IhHqBoi5vwc61d7GHxm6Hw.jpeg
It was used for indoor filming. The camera would mount on top.

 

[gmax137]

Here is my recently bought Yashica Electro 35 rangefinder camera (from late 1960s to early 1970s).
Quote from Wikipedia: "It was the first electronically controlled camera."

I won it recently at an online auction for about $66. It is in marvellous condition (near mint).

I bought it for nostalgic reasons; my father had one and it was one of the very first cameras I used as a child.
It was amazing to get a hold of one, since I started to remember all the controls and even the look in the viewfinder. I even recognized the smell of it, actually!

It may very well work too, and I am thinking of trying to use it some day.

Wow that's amazing condition. Is that an f1.7 lens? Nice. If you ever get tired of it let me know :)

 

[DennisN]

Is that an f1.7 lens?

Yes. And the lens is fixed to the camera, so it can't be used on other cameras without using violence.

 

[DennisN]

If you ever get tired of it let me know :)

I was keeping an eye on Ebay for a while for Yashica Electro 35, and there were/are items available in various conditions between ca $70 and $140. I saw one in excellent condition for about $140 available for shipping from Japan, and I was considering it for a while. Later, I was lucky to find my item on a Swedish online auction site for a much better price, so I went for that one.

 

[dlgoff]

Now that's some beauty. Thanks for posting it here.
"...and I am thinking of trying to use it some day."
Which makes it even more beautiful.

 

[Tom.G]

Nice camera. Let's hope it works and that you can find some film to fit it.

I like the atomic logo too.

Both Kodak and Fuji still make 35mm film, readily available too!