I’m embarrassed to admit how many sampling heads I tried before I realized I had the wrong vertical mode selected.
5. It was 5.
Also the graticule lights just went out, and the readout is on the fritz again (both voltage and time displays are incorrect). I seem to remember that from this mainframe. The Tektronix readout system on the 7k series is the work of a mad genius.
#tektronix #oscilloscope #1980s #retroTech

I went to the Artisan's Asylum and found someone who was attempting to repair this beautiful CRT oscilloscope by Tektronix.

It got worse before it got better. The #tektronix 7D20 digital #oscilloscope plugin had 3 bad RAM chips, as indicated by the self test, which caused some anomalies in the displayed waveform, but no other issues. I removed the chips and put in sockets, but one of the replacement 4116 RAM chips was also bad, in a way that caused the entire display to go south. I didn’t realize until a read through the manual that the waveform memory is also used to store readout data in its way to the DACs.

Well…. Shit. I was going to fix some RAM issues with this #tektronix 7D20 plugin, but it seems to have developed a display issue

About five years ago I had six working Tektronix FG504 signal generators, most of them quite seriously repaired after I managed to find eight of them, but with only one working as-found. They are fantastic but also fragile (and 40-50 years old): yesterday I was again down to only one working generator: time to start on those postponed repairs.

#Tektronix #79 #SystemsThatMatter

Found a low mileage #nikon D810 for a good price and decided to take the plunge.
Here’s a #tektronix type O operational amplifier plug-in in a Type 132 power supply, which lets one operate a plug-in outside of its host #oscilloscope.
2 flash setup, one with a soft box, the other a bounce. 105mm #macro lens.

It feels like it’s been a bit since I posted an oscilloscope photo, and that feels wrong.
So here’s a #tektronix 7854

Finally got back to getting the stop comparator card repaired in the 567 / 6R1A. It was a bad tunnel diode after all. You can see the curve has a super weak negative resistance region (the dip where the curve changes direction); it's supposed to be much more pronounced.
#tektronix #oscilloscope #analog #retroTech

Spent some time today trying to reduce the ringing on top of this PWM switching of a 200W load. Nice to be using that oscilloscope again.

#Ringing #Tektronix #79 #SystemsThatMatter

Battlestar Galactica (1978)
Tektronix computer 405x series
Direct view storage tube
#scifi #Tektronix

I'm starting to do the repair in this video:
TDS220

https://www.youtube.com/watch?v=weUSGjzEoVM

Voltage measurements starting to show signs of life after swapping out a few bum transistors in the 0% zone card. The 0% cursor isn’t working yet, so I don’t know where it’s measuring from, but I can get changing readings by moving the 100% cursor. The change roughly corresponds the peak to peak amplitude, which is promising.

Got time measurements working via manual cursors. Problem was in Stop Comparator card. Did a swap for now, but suspect Q54, will do component level troubleshooting next, but for now happy to get this closer to working.
0% zone still not working, which means no voltage measurements, and thus no automatic risetime measurements; that’s next on the list.
#tektronix #1960s #oscilloscope #electronics #testEquipment #retroTech

Important safety tip, thanks Egon
#tektronix #electronics #1960s #retroTech

Next on the bench, the Tektronix 567 oscilloscope with possibly the first digital readout facility on any oscilloscope.
Swapping a bad tube in the regulator got all the rails up to spec. A few bad Nixie tubes in the readout unit were swapped, and now the real troubleshooting begins.
#tektronix #tek567 #oscilloscope #1960s #electronics #testEquipment #retroTech

This was an easy win. Pulse generator initially had a slow rise time. Some disassembly, cleaning and reassembling got it working properly.
#tektronix #1960s #electronics #testEquipment #retroTech

Look at this sexy-ass piece of engineering. Check out what happens when smart people harness downright magic.
It reminds me of the onion headline “Humanity Still Producing New Art As Though Megadeth’s ‘Rust In Peace’ Doesn’t Already Exist”.
Imagine seeing this and thinking “oh sure, but I’ll make something better”. GTFO, no you won’t. It’ll be faster and more accurate and cheaper and lighter and have a fucking touchscreen and USB, and a fucking subscription, and it’s going to have the soul of a republican, and every time you touch it, an MBA will get an erection.
GAH, this is just so damn pretty.
(And Rust in Peace is an epic, seminal album)
#tektronix #electronics #1960s #retroTech #rant #oscilloscope

Heck yeah!!!
Finally fixed the slow unblanking issue in this rather unique horizontal plug-in for 560 series #tektronix scopes.
TL;DR, it was R268, which went high. Not so high as to sway the voltage under no load conditions, but squishy enough that it effected the rise time when current was to be driven into a capacitive load.
Thanks for the assist @kurt!