My first scope, a Tektronix 11401 with option 2D extended memory and two 11A34 plugins and an 11A33 plugin.


The 11k series, and the elusive 11401. Almost all google searches result in low double digit number of results. The ones that do return a large number of results are mostly user manual sales. The 11401 and other 11000 series sadly has missing extended service technical documentation and I've only seen prototype pcb pictured. There are some cool 1980's 11000 series marketing materials from vintageTEK on youtube and single self test videos on youtube and that's about all I could find. No one seems to care about them largely and It seems to be almost forgotten. Outside of a handful of sites, and a tiny number of posts and pages from the likes of tekwiki, evvblog,, and plus the wayback machine, the internet archive, and ArtekManuals. There is nothing. Compare that to a 453, or the 7854 you get millions and millions. I mostly resorted to scouring the old 1986, 1987, 1988 Tektronix product catalogs for my cross reference knowledge on the machines general capabilities, recommended probes for each plugin, plugin compatibility. Yeah yeah, read the manuals. easier said than done as I had to find them first. People talk about dreading working on their 11400 scopes. But a quoted service center tech said, "The 11400's are boring to fix; they're no fun to troubleshoot because the diagnostics finds the problems so quickly and easily." I'm sure it's mostly marketing but the 11400s were engineered from the ground up with self diagnostics in mind. They offer a very wide range of features and really is the pioneer of DSOs. (probably why they later code named it 'pioneer', if not ... wow that foresight)

Why should anyone care about the 11k and largely the 11400? Do I have buyers remorse?
The Tektronix 11400s brought high expectations and new standards for what a digital scope is and what it could be. The 11k line brought to market advanced triggering, storage, full hardware and firmware program-ability, Live operation, high accuracy, high resolution, multiple channels, plugin modular-ity, 7k plugin compatibility, self calibration, self diagnostics and a freaking touch screen interface + many other features that all good DSOs have today. Going by today's standards almost all of those features are vital. If it were not for the 11k series and largely the 11400 line, i believe the Modern Digital Storage Oscilloscopes probably wouldn't be what they are today. I feel there is enough room for argument to say that the bench-top DSO would probably be nothing more than a pico pci-e card or a phone with a usb dongle if it were not for the 11400s. Why? Well first, everyone was watching Tektronix after the 7854, how could you not? With eyes on them, they had to do something bold, and I believe they did just that. The 11000 series was released in 1986, only 5 years before pico technology. The DSA600s released in 90. Talk about breathing room. If Tektronix didn't go where no scope designer went before, and released just another analogue scope with 500 buttons instead of 250, or a mediocre DSO with 250 buttons, the DSO wouldn't have progressed like it had so vigorously with the 11000s into what they are today. They wouldn't have had time to engineer the 11k line if they made a 500 button analogue or a 250 button DSO first, pico tech would have came out, and with the accessibility of the microprocessor ruling the world. I don't see how DSOs would have been relevant. The 11400 wasn't designed for today in 1982-1986, it was designed for today in 2020. All modern oscilloscopes should look to the 11ks and largely the 11400 for their grandscope. Sure 11ks only have 20 mega samples per second, but it's cousins the DSA600s with plugins like the 11A72 can get you to 500Mhz @ 2ghz sample rate. Truly mental for the 1990s. Anyway, just an afterthought I had floating in my brain, but maybe you can see how if it were not for machines like the 11400s which came out in a crucial time right before mass pc computers and pico technology the mighty DSO might just have become just another piece of software on a laptop or another apple dongle. I think we can almost all agree that this was for the better. The 11k series to me, is likened to zx spectrum, the bbc micro, or commadore 64 of oscilloscopes. The one that started it all. And if you ask why hasn't pico become more popular ? that i think is because established companies were already making DSOs before we were blessed with the pico. so much was already invested into what modern DSOs were to become. so there was no room for pico.

What are my plans with this machine? No... I don't have buyers remorse what makes you say that?
I got this largely for the 11k plugins it has in it, notably the differential comparator, also 2-4 channel amplifiers lol, the mostly working mainframe with Option 2D - Extended Memory is a bonus. My plan is to use this as my first scope, and fix it until I feel like i need breathing room and as i can easily upgrade into a DSA602a while still using the plugins, once i collect enough excess 11k plugins and probes, i plan to get a 11302a and have a very decent set of retro-ish scopes. Currently awaiting arrival. I will update this topic, post pictures, and I will be posting videos on youtube about this scope as this is almost nothing about it online. Im currently in research and developing a robot with multiple dual core 64 bit risc-v chips and fancy mechanical 3d printed parts.

Onto the now hopefully rose tinted machine itself.
I just picked up this Tektronix 11401 with Option 2D - Extended Memory, it came with two 11A34s and an 11A33 from ebay for 199, and 50 usd shipping. It came from a university who's upgrading. Overall seems decently kept for a machine built in 1986. I also swooped up a few P6134c, P6134 and P6135's probes. I also went over to ArtekManuals and bought the 4 volume manual set they offer. I believe that they have the 2 missing extended service manuals i cant find on the open internet. The machine passed almost all of its self tests with a single fault on the TimeBase Test with fault code G2121. There is also a penciled X by channel 2 on the far right 11A34, possible dead channel?. My initial thought without reading the manuals because they haven't arrived yet, is that the timebase G2121 fault is from that pencil'd x channel that could be dead as its marked with a x. lol.... honestly no clue, it's what i can tell from the photo and knowing nothing about the machine or really electronics engineering, im a software guy who just recently fell in love with the programming language of solder! The machine hasn't even shipped yet! Im typing this as I eagerly await my boat anchor. You and I will find out more when it arrives. in the mean time, i await the service manuals and i get to read the user manual :D !!! Wait who reads these anyway?

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