Old HC 5502 analog scope ( some display problems )

[cowboybob]

The suggestion (from KISS) to utilize the built-it 1kHz, 1V PP signal would answer some questions I have as well.

The "Cal" test point display will tell us loads...

And one additional piece of info that will at least better describe your set-up is: what are you using for a probe?

If you don't want to do any of the above, Does the "Volts/Div" center adjustment allow you to bring the display to the number of divisions you think the scope should be displaying with the input you're giving the scope?

 

[KeepItSimpleStupid]

On this photo taken from here: https://www.google.com/imgres?biw=1276&bih=605&tbm=isch&tbnid=V7anMSq9I7X4jM:&imgrefurl=https://www.cliftonlaboratories.com/july_2007.htm&docid=GxR4oJqSXMWk4M&imgurl=https://www.cliftonlaboratories.com/userimages/Update204.jpg&w=400&h=300&ei=5lbgUorIEdHLkAfTqYCQDQ&zoom=1&ved=0CHIQhBwwCg&iact=rc&dur=2716&page=2&start=10&ndsp=15

is set to 1 V/div.

The divisions are major divisions, just like "graph paper" which might be an unknown for you.

CBB: His pic of the from panel clearly shows channel 2 in uncalibrated mode. That' the inner dial on the volts/div switch. It should click in the CAL position.

 

[cowboybob]

Exactly. But since it's out off detent (Cal), that direction of motion always reduces the amplitude of the display. With his indications that the display is displaying a greater number of divisions, there's no telling what's going on for sure. For that matter, not all that sure about the actual input sig specs...

Great idea to put up that pic.

If he'll just use the cal sig (as you mentioned and generally more reliable for signal purity in all aspects) we'd have a better chance of helping. And, of course, the probe could be wrong, dorked, not a probe and so on.

 

[KeepItSimpleStupid]

CBB:

As far as i understand 1 square's Y axis has 5 divs

Note what the OP said: 1 SQUARE is 5 divisions. So he could already be factor of 5 off. The fact remains, i have no idea what channel he used and channel #2 is not in the Cal position. The OP is using the minimum markings as a division. It's not.

Heck, we don't even know if he's using a X10 probe?

Fell like going over what the knobs do?

 

[cowboybob]

KISS, interestingly, found this:

https://www.electro-tech-online.com...l-protek-p3502-hung-chang-oscilloscope.92595/

Maybe BGAmodz can get it all from us after all.

Just don't have to re-invent the wheel...

(It's a good link, just downloaded the manual).

 

[rumpfy]

You're in luck BGA, cos the manual looks really good.
You've had a lot of advice, but my recommendation is to get the manual in your hot little hand, sit down without interruptions from anywhere, and read the manual while fiddling with the controls.
There are a lot of features in the cro and you need to understand them all, and you will then find what an indispensable tool they are.
When you find something you dont quite get, then come back and ask, with reference to the manual. Then we'll be all on the same page.
Thanks to the cowboy for finding the reference.

 

[BGAmodz]

the probe could be wrong, dorked, not a probe and so on.

CBB:



Note what the OP said: 1 SQUARE is 5 divisions. So he could already be factor of 5 off. The fact remains, i have no idea what channel he used and channel #2 is not in the Cal position. The OP is using the minimum markings as a division. It's not.

Heck, we don't even know if he's using a X10 probe?

Fell like going over what the knobs do?

Yes i thought minimum markings were a div LoL , but the settings of v/div mean one volt per major division right ?


And also my probe has an output like DMM input probe witch i connect to crocodile clips not like the original one with 2X and 10X switch ( i have them but they are not working ) .

Currently using channel one , and set the v/div knob to cal postition (until you feel a click ) .

 

[BGAmodz]

You're in luck BGA, cos the manual looks really good.
You've had a lot of advice, but my recommendation is to get the manual in your hot little hand, sit down without interruptions from anywhere, and read the manual while fiddling with the controls.
There are a lot of features in the cro and you need to understand them all, and you will then find what an indispensable tool they are.
When you find something you dont quite get, then come back and ask, with reference to the manual. Then we'll be all on the same page.
Thanks to the cowboy for finding the reference.

Thank you , and all the other members , also great thank to cowboybob for the manual .

 

[KeepItSimpleStupid]

Yes i thought minimum markings were a div LoL , but the settings of v/div mean one volt per major division right ?

Well, V/Div means V/(Major Division)

Also, take a look here for p-p and (0-peak) to RMS: https://wiki.answers.com/Q/Convert_peak_to_peak_voltage_to_rms?#slide=1

 

[BGAmodz]

Hi again .

I just want to tell that the unit is showing signals the right way , the new probes i got can switch from X1 to X10 .


One thing still to be done is getting rid of that flickering , its really bad for the eyes .

 

[KeepItSimpleStupid]

Check the calibrator signal. It should not flicker. 60 Hz, I think will, just because of the frequency.

And learn how to compensate the probe. In th x1 mode, you can't compensate, so the calibrate signal might not be square.

On most x1, x10 probes a screw gets exposed in x10. Adjust, so the edges of the "square" wave is square.

 

[rumpfy]

BGA,
I repeat there's heaps of stuff in the manual. Just get it all into your head.
At this stage don't worry about the flickering; it wont change your ability to get acquainted with the controls. If its going to bog you down, you'll have to fix it. The Z modulation is given on page 34b.gif at P405 pin 1. On page 05.gif of the manual, reference is made to item number 30. This is the 'Z axis' or 'intensity modulation' and I believe that this part of the cro is playing up. I might be wrong here, but you need to get to know what the knobs do as a first step. JUST FOLLOW THE MANUAL.
They dont say what timebase speed setting is used for the calibrator, so fiddle with the 'Time/div' knob until you see something sensible.
Good luck with it; you'll love it when you can use the cro with flair.

 

[BGAmodz]

Hi guys , back on topic again .

.I just want to point out another issue with my old scope , this time its the display of a square wave , when i want to display it i only got to choose 50 ms sweep or bellow to see the total square wave showing up , but the problem is i get like an up/down moving dot and not a square line wave .

Is this something related to the flickering i already mentioned ??

 

[cowboybob]

Is the square wave from the built-in source?

What is (are) your trigger setting(s)?

Are you saying there is no (none, zero) horizontal movement of the sweep when you select anything above 50ms?

 

[BGAmodz]

Is the square wave from the built-in source?

What is (are) your trigger setting(s)?

Are you saying there is no (none, zero) horizontal movement of the sweep when you select anything above 50ms?

hi cowboybob ,

square wave is created using a 555 ic
And actually there is a normal sweep and horizontal movement in every time/div setting but the problem is that when i choose a setting that should show the full square on the CRO screen i get movement of the sweep but the movement is like a dot sweeping alone going high or low , you don't see a complete square form just a traveling dot , its like the sweep is not fast enough to show a clear square form ( like on post 22 ) .

BTW i have encountered this also on the sine wave but i get a flickering instead .

 

[cowboybob]

What's the frequency of the 555 output you're using?

And when you're displaying one full square wave, what is your sweep speed?

 

[BGAmodz]

Its 0.5 hZ , the schematic is attached bellow btw.

I don't have a sweep speed control only got sweep mode and its set to auto .

 

[KeepItSimpleStupid]

At 0.5 Hz, what you should see is a dot going across the screen. There is almost nothing to trigger on especially with Auto trigger. You do have 0.1, 0.2 and 0.5 s per division.

You will not see a square wave, but you should see a square wave "traced" as a moving dot.

 

[BGAmodz]

At 0.5 Hz, what you should see is a dot going across the screen. There is almost nothing to trigger on especially with Auto trigger. You do have 0.1, 0.2 and 0.5 s per division.

You will not see a square wave, but you should see a square wave "traced" as a moving dot.

Its exactly what i see a moving dot with slow frequency .

i will try with higher frequency and see how this looks .

 

[KeepItSimpleStupid]

I think it will look like two alternating lines every 0.5 sec.