What did you do with or to your oscilloscope today?

[richnormand]

Seldom used:  the X-Y mode of my Tek 7D20 plugin to frequency adjust and beat the 10 MHz output of a Morion double oven OCXO against a Trimble GPSO.
Once the Lissajous pattern has stabilised it will stay put up with mHz... not bad at all.



 

[RoGeorge]

For the XY mode, this Loch Ness monster!   



It's the I-U characteristic of a 45 years old photodetector from a former punched cards reader, when the photo detector in series with a 10kohm resistor is swept with a 18Vpp 1kHz triangle signal from a generator, while illuminated by a halogen light bulb.



The tale of it is I was trying to find out if the photo detectors were photoresistors, photodiodes or phototransistors.  Turned out to be NPN phototransistors with access only to EC, while all the E were tied together (E were the cases of each of those small glass dots lined up in that trace of solder), so one ground and 12 more wires from the C of each NPN phototransystor to optically read a full character at once, from a punched card, yes, with wholes, like this!   
(Note the line of characters typed on top of the card.  Each column of punches encodes one character.)



The picture of the punched card is from https://vintageisthenewold.com/living-like-the-pioneers-code-fortran-in-a-punch-card/  Their copyrights, if any, not mine.

[richnormand]

Well that brings back memories!
I spent lots of time with FORTRAN and assembly language on the IBM 1130 and 360s in the days.
I still have the habit of having a small paperclip on my shirt pocket from spending hours at the keypunch and reader. Paperclip was used to unclog the card vacuum pickup arm...

[rstofer]

Well that brings back memories!
I spent lots of time with FORTRAN and assembly language on the IBM 1130 and 360s in the days. 
I still have the habit of having a small paperclip on my shirt pocket from spending hours at the keypunch and reader. Paperclip was used to unclog the card vacuum pickup arm...

Maybe http://ibm1130.org/ will bring back some memories! 

I built an 1130 in an FPGA about 12 years ago and I still use it from time to time for FORTRAN and the Plotter Library.  I also have the IBM Circuit Analysis Program (ECAP) and the Continuous System Modeling Program (CSMP).

I started using that system in 1970 and it remains a fond memory.

[karamba]

Well that brings back memories!
I spent lots of time with FORTRAN and assembly language on the IBM 1130 and 360s in the days.
I still have the habit of having a small paperclip on my shirt pocket from spending hours at the keypunch and reader. Paperclip was used to unclog the card vacuum pickup arm...

I also had a paper clip but for a different reason. I helped to fit punched out pieces back into the holes if we needed to fix something quickly. Yes that's how backspace worked back in the days. :-)

[dxl]

Been trying to read the nvram contents of my TDS640A. So far, no luck.  Also trying to get the service port connection to work with a cable.  No luck.

Is that on top of the scope your service port adapter cable? I think it's way to long. When i originally reverse engineered the console port, i used a 4" ribbon cable. Remember it's a processor bus running with several MHz on that cable.

[blackdog]

Hi,

These are the last measurements I took with my scope.
It's the timing of one of the four pushbuttons that determine the range of a current transformer.

The yellow trace is the switch pulse, this provides without delay all four reset coils of the bipolar relays with two coils.
The blue trace is the pulse for the reset coils and is 20msec long, this is 3 times as long as needed and I find this a safe margin.
Then there is a dead time of about 34mSec after which the green trace becomes low and the "set" coil of the selected range is energized.
The timing is chosen in such a way that you can change range almost twice a second, but I don't see why I would want to do this so quickly. 


.
And this is  the schematic, setup for using no power if no switch is used, it is for a battery powerd device.


Kind regartds,
Bram

[vk6zgo]

Well that brings back memories!
I spent lots of time with FORTRAN and assembly language on the IBM 1130 and 360s in the days.
I still have the habit of having a small paperclip on my shirt pocket from spending hours at the keypunch and reader. Paperclip was used to unclog the card vacuum pickup arm...

I also had a paper clip but for a different reason. I helped to fit punched out pieces back into the holes if we needed to fix something quickly. Yes that's how backspace worked back in the days. :-)

Not early computer oriented, but your comment reminded me of when we sent a daily report via Telex.

To this end, we had a teleprinter & a tape reperforator.
The normal method was to type up the report & produce a tape, then run the tape to send the message.

There was a lot of stuff which didn't change day to day, so we would make up short tapes with such things on them, stop composing the day's message where they fitted, run the short tape & add the information to the daily tape (our setup could do that).

We were pretty much doing "cut & paste" in an "old school" way.

We were also required to keep each day's  tape for several days, so along with the above mentioned "short tapes", it added up to a fairly messy pile of them on the desk.

One of the guys became sick of this, & I came in to work one morning to find them all attached to the felt notice board with thumbtacks.

"Gee, that's neat", thought I, & didn't think anymore about it, until we tried to run one of the tapes, when we found a problem.

Perforated paper tapes don't like having extra random holes added!

For the tapes already removed from the board, it was a matter of taking them outside in the bright sunshine & looking for holes that didn't quite "look right", covering them with Sellotape, testing, then making a replacement.

With the undisturbed  ones, it was just a matter of marking them where the pin went through, then doing the "Sellotape" thing, & so on, but the whole process still wasted a couple of hours.

[shakalnokturn]

Checking how much "bounce" there is on silicone/carbon keys makes me feel happy on a rainy night.

[keystone]

Been trying to read the nvram contents of my TDS640A. So far, no luck.  Also trying to get the service port connection to work with a cable.  No luck.

Is that on top of the scope your service port adapter cable? I think it's way to long. When i originally reverse engineered the console port, i used a 4" ribbon cable. Remember it's a processor bus running with several MHz on that cable.

Yes, that's the console port cable I made.  I got the cable that way from digikey.  In the instructions for building that, nothing was ever said about length.  I'll see if I can shorten it to about a foot and see what happens.  Thanks for noticing that.  

[RoGeorge]

Checking how much "bounce" there is on silicone/carbon keys makes me feel happy on a rainy night.

What are "silicone/carbon keys" (for)?

[shakalnokturn]

Checking how much "bounce" there is on silicone/carbon keys makes me feel happy on a rainy night.

What are "silicone/carbon keys" (for)?

Whatever they're called... They are used as momentary push-to make switch contacts. Usually found on your TV remote control or Rigol DSO.
Are they better known under other names?

[RoGeorge]

I misread silicone/carbon as being something about Silicon Carbide based contacts, my bad, sorry.   
Sometimes I call them rubber cap keys, or flexible keyboard, no idea how they are really called.

[tautech]

I misread silicone/carbon as being something about Silicon Carbide based contacts, my bad, sorry.   
Sometimes I call them rubber cap keys, or flexible keyboard, no idea how they are really called.

Membrane keypad. 

[Grandchuck]

Took the recharging coil out of an old electric toothbrush and thought a look at the induced waveform might be interesting (and added an LED across the coil to see if it would light up).  Obtained an interesting waveform!  Yes it does light up as one can tell from the waveform.