Help - What does 10 mean resistor schematic???

dl324

Joined Mar 30, 2015
12,790
Ask around on this and other fora. I don't have any of these, but lots of geezers have lots of old parts. Many will send them out for the cost of the shipping.
I have a dozen CA3080 in metal cans that I bought in the 70's. They're unobtainium now...

EDIT: well not completely unobtainium. Apparently this place sells the metal can version for $13 and has hundreds in stock
http://store.americanmicrosemiconductor.com/ca3080.html?gclid=CMzokqCw4NICFUKUfgodeFcOhQ

This article said OTAs were going to make opamps obsolete...
 

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ColoradoRobert

Joined Jan 22, 2016
155
It's interesting and concerning that on your site (dl324), only has 1 spec sheet comes up for the 4 they offer - they either have a letter after or the one does not. Those letters afterwards (I can theorize more), must mean something? My original is CA3080 AE and I wanted to compare all replacement leads with what Mouser shows these originals were as far as the specs go.
 

dl324

Joined Mar 30, 2015
12,790
Those letters afterwards (I can theorize more), must mean something? My original is CA3080 AE
CA3080 and CA3080A have slightly different specs, with the 3080A having higher guaranteed minimum gain.

The E in your part number indicates PDIP package.
 
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ColoradoRobert

Joined Jan 22, 2016
155
I had to look it up dl324 and the definition bring me back to my earlier theory = if pdip means:
"two parallel rows," then why wouldn't an ohm meter be able to show that they are at least
joined together? BTW, 3 parallel show conductivity while the last row shows nothing.
 

dl324

Joined Mar 30, 2015
12,790
then why wouldn't an ohm meter be able to show that they are at least
joined together?
Unless there are protection diodes not shown in the schematic, you can only check D1 or the BE junction of Q3. Those junctions being good in no way means the device will function.
upload_2017-3-18_9-33-0.png
BTW, 3 parallel show conductivity while the last row shows nothing.
What does this mean??
 

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ColoradoRobert

Joined Jan 22, 2016
155
Journey down my very-novice and theory road. This is how I do a test using my ohm meter and this is what I mean when I say parallel. Even if it makes no sense to you pros, it does show there is some conductivity between pins. All the opamps test showing something except for the last row on this U9. Also I can jump horizontally and the pins will show conductivity except when touching row 4.
 

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dl324

Joined Mar 30, 2015
12,790
Still can't follow what you mean. If you're doing these measurements in-circuit, they're meaningless unless you have a schematic to see how things are connected. Aside from diode checks, resistance measurements are essentially a waste of time.
 

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ColoradoRobert

Joined Jan 22, 2016
155
All I can suggest at this point is take your trusty and dusting ohm meter off the shelf,
get a spare opamp and touch your + and - to row 1 of the drawing = needle will move.
Next row 2 then 3 then 4. All will move the needle unless it's like my opamp that will not
move the needle on row 4 to 4 or 3 to 4.
 

MrChips

Joined Oct 2, 2009
23,226
All I can suggest at this point is take your trusty and dusting ohm meter off the shelf,
get a spare opamp and touch your + and - to row 1 of the drawing = needle will move.
Next row 2 then 3 then 4. All will move the needle unless it's like my opamp that will not
move the needle on row 4 to 4 or 3 to 4.
Sorry. What you are saying is total crap. You are wasting your time.
 

AnalogKid

Joined Aug 1, 2013
9,174
The internal connections in a complex integrated circuit such as an opamp cannot be measured/tested/verified with an ohmmeter, and whatever you do measure has *no* relationship to the chip actually working. No matter how many times you ask the question, the answer will be the same. Between two pins there could be a dozen semiconductor junctions, which would require more voltage to excite than most ohmmeters produce. Or there might be only one, which a meter might interpret as a short even though its just a diode. And all of that is confused by the body diode in the substrate.

Using a protoboard, a very simple circuit can be used to perform a basic function test of an opamp.

ak
 

wayneh

Joined Sep 9, 2010
17,143
Sorry. What you are saying is total crap. You are wasting your time.
I agree. No power = no useful data. The bit above about testing an appliance without applying power is a good analogy, but understates the waste of time. You can learn some things about some appliances without applying power, but not an IC. Worse, you could damage some ICs by applying the meter leads without the IC power pins tied to a power supply

If I need to test an IC, I build a test rig on my breadboard so that I can apply power and probe the various functions. Similar parts, such a dual op-amp ICs can be screened in bulk that way, one after the other. There's really no other way.
 

RichardO

Joined May 4, 2013
2,271
All I can suggest at this point is take your trusty and dusting ohm meter off the shelf,
get a spare opamp and touch your + and - to row 1 of the drawing = needle will move.
Next row 2 then 3 then 4. All will move the needle unless it's like my opamp that will not
move the needle on row 4 to 4 or 3 to 4.
If you are using an analog ohm meter you can actually premanently damage an op-amp and other semiconductors. :eek:
 

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ColoradoRobert

Joined Jan 22, 2016
155
Someone should market a cheap tester for opamps if there is not one out there already; there probably is. While you guys understand more about circuits and give me a good warning not to jumper these.... I have to report that I have been doing it for awhile and I guess I've just been lucky. Also, while you all agree that my form of wasting my time means nothing (as testing goes), I do not think that any of you would disagree that each pin is connected to something, right? So to me if I cannot pick up even the slightest trace of anything happening when I jumper pins (backwards and forwards) then that cheap component is suspect and I will risk six dollars to see if my theory works, that it needs replaced.
 

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ColoradoRobert

Joined Jan 22, 2016
155
Thanks dl324 but I am going to risk the 6 bucks and wait probably 20 days to get it from China. In the meantime, thanks to the person who gave the warning about fake components from China. That lead me to send the Mouser specs of the opamp to everyone of them.... asking if what they are selling matches the specs from the Mouser page. That was a very good idea because I actually had that happen before. I got 10 chips from China and they did not test like the good one I had. The difference was there's was a single opamp construction and the one off the board was a dual yet they both had the same numbers written on them.
 

RichardO

Joined May 4, 2013
2,271
While you guys understand more about circuits and give me a good warning not to jumper these.... I have to report that I have been doing it for awhile and I guess I've just been lucky. ..... So to me if I cannot pick up even the slightest trace of anything happening when I jumper pins (backwards and forwards) then that cheap component is suspect and I will risk six dollars to see if my theory works, that it needs replaced.
Some details on the dangerous current from an analog meter. Go down a ways in this thread to see what the current of a Simpson 260 could be while measuring resistance:
http://www.electro-tech-online.com/...nce-at-low-currents-vacuum-tube.139247/page-4

Spoiler: There is a picture of a digital meter reading 184 ma from the Simpson 260 while it is reading a 1.5 ohm resistor. :eek:
I just noticed that the post was done by a member of this forum. Thanks @Reloadron.
 

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ColoradoRobert

Joined Jan 22, 2016
155
Those are deep waters RichardO, I did read a few comments but it seemed mostly about a discussion on the model of Simpsons. I had an old one and the body appeared to be plastic semi-glass like. But that was at work and they could afford it now I just have a cheap radio shack.
 

RichardO

Joined May 4, 2013
2,271
Those are deep waters RichardO, I did read a few comments but it seemed mostly about a discussion on the model of Simpsons. I had an old one and the body appeared to be plastic semi-glass like. But that was at work and they could afford it now I just have a cheap radio shack.
What I was trying to show is that some analog meters put out a _huge_ test current while doing a measurement. Unless you _know_ that your meter won't put out damaging currents you must assume that you will permanently damage any IC you test with it.
 

Thread Starter

ColoradoRobert

Joined Jan 22, 2016
155
Yes I understand what you are saying RichardO and Thank you for sharing the information. I believe what everyone has said about it also. I guess I've just been lucky so far. BTW, I am not doing this for others, I am doing these repairs for myself. I am very much a novice at it all. That's why I pose the questions here because you are the guys that really know.
 
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