Quote from: nosaj on October 20, 2023, 03:21:56 PMIf you need a probe to measure the HOT wires i have a 30kv probe you can have for shipping.
nosaj

that is very kind of you i appreciate the offer if i get it i def want to pay for it

a question i had...do HV probes eliminate all the fireworks (arcing, sparks flying..) that i got with my normal multimeter probe ?

 

edit...nm i watched some videos where really high voltage was being probed and there were no fireworks...maybe the density/girth/resistance of the hv probe helps

well guys i wanted to get this over with the suspense was killing me so i looked at all the markings on my newly acquired stash of ICs
I was dreaming that I was the proud owner of mass quantities of rare impossible to find NLA components....
I was at the least hoping for something I could use in my Heathkit scope...the closest thing was the last one listed..but i need a plain ol 74132
when the one on the sheet is googled...lots of aviation stuff pops up....

anyway here we go.....


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so now that is over with i dug in there and found this and really like it
but have no idea what it is
ok nm its a baby transformer
 

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anyhow have a great weekend

That looks like a standard audio transformer to me, i don't know what from as my background was industrial electronics.
It would be used to isolate the audio signal between 2 different circuits.

Why do you think the DV74HC132AN will not be the same as the 74132 you need ?
It can handle up to 7v supply and you have 4.8v supply in the scope.
If the chip can handle the voltage and signal then it should be ok.
Hopefully someone who knows for sure can jump in with an answer for you.

The LM358 dual opamps will come in useful in many projects, you could use one to buffer the sinewave output of the ICL8038 signal generator IC that you got there.
The ICL8038 has square, triangle and sinewave outputs and will make some great signal generators for you to build.

Yes, the 74HC132 is backward compatible for 74132 usage.  The DV is just a brand prefix I believe.
The audio transformer might have been used for mic inputs, as 500 Z impedance is probably close enough to the standard 600 ohm.
Here's one in use for matching PC sound card out to PA mixer mic input:
https://sound-au.com/project133.htm

hey guys I had a question about circuit board layout specifically why are components clearly labeled but not resistors

as an example I am (randomly..) finding voltages on the schematic and then testing

for instance I want to see if there is 9v on one end of R109

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now...D103 is easy to find..anode and cathode clearly marked

that is easy enough..

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but now when I want to measure R109 its not marked and I am guessing...aside from the color code can help

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idk if that was the right one..

so that is my question why not label the board R109 etc

 


btw i am putting this scope away and coming back to it when I learn a bit more

ok nm i guess you need to see the bottom of the board where the traces go

A zero ohm reading between components would confirm a connection without flipping the board.

I think it should have been marked, but then in the stomp-boxes I make up there is no room so my markings are under the components.
Once you mount a resistor you can no longer see what the part number is in most of my PCB's I make up.
But then my PCB's are for myself, and anyone I share them with on a forum.

hey guys i just wanna say thanks again for all your help i figured it might help to post a pic of myself so you can put an ugly mug to my inquires

anyhow this was just now..cleaning out my garage sweeping out racoon scat on a beautiful (finally) sunny fall day

 moving a gun safe probably gonna sell it

gettin rid of a few things

 etc

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yep im old just turned 60

im grateful i found this hobby I have a lot of personal achievements, accomplishments and failures but i was always intimidated and bewildered by anything electrical

you guys rock

\m/

I decided to quit trying to fix my heathkit scope until I have a bit more skills.  I dont want to butcher it to the point where it becomes a basket case.  Im encouraged that some of the measurements I have taken are in agreement with the schematic. Also that one board that has some rusty (trimmer pots?) I was expecting the bottom to be beyond recognition but instead when i flipped it over it was nice and shiny...really looked awesome. I also got ahold of a hv probe i wanted to measure that 1640 or whatever it was and i still got a ton of fireworks..sparks and arcing.
so yeah im putting it away for a while before i kill myself or it and getting back to doing my little experiments in my book.
which i just finished chap 2 (diodes) and it got pretty heavy with dynamic and bulk resistance, junction voltage, operating points or load lines...cant remember.  you draw lines when If equal zero and Vf equal zero with different resistors etc which i wasnt crazy about but figured its necessary just suck it up and get through it so I can get to the good stuff.
which kinda happened so here i am

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this should be exciting

im looking forward to doing the experiments

all i know or think is zener diodes are kind of like backwards diodes...idk 

 

Quote from: saturated on November 02, 2023, 07:29:17 PMall i know or think is zener diodes are kind of like backwards diodes...idk 

 

Almost.  Standard diodes only allow current in one direction, zeners can flow in both directions.  Zeners will operate similar to a standard diode in forward mode, but in reverse at breakdown voltage they allow current without letting out the magic smoke.

hey guys
hope you are having a good holiday(s)

I have decided in the interest of thoroughness to go back and start an earlier book to the one that i was doing

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so yes its a step back but i dont want to miss anything and the best thing about this series of books is each chapter has lab exercises

anyhow wanna give everybody a big shout out
stay safe


and keep on rockin \M/

 

I have been having this old decade box for a while and kinda didnt have a use for it.
but then in my book breadboard experiments i needed a few resistors that I didnt have
then was groaning about ordering more 

took me a while to figure it out 

but maybe i can use this

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some of the resistances arent too close but check this out

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I was getting mad at my cheep aukenien resistors but I was incorrectly not using the fourth band as the multiplier

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I also tested some old stuff and learned that 3 bands means 20% tolerance

I still like the old resistors better the colors are awesome


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