This is my first fully digital scope. I'm not sure that I'm a fan of this technology just yet.
...and here we go. Always a crap-shoot whether an old scope will boot up properly.
You might have noticed that the focus isn't all that great. Unlike the other Tektronix scopes I have accumulated, this one doesn't have a knob for adjusting that. I had to use a jeweler's screwdriver to adjust a small inset screw. It just seems a little odd, because focus does seem to drift frequently enough to justify having a knob to adjust for it.
It sure as hell doesn't display like the others. I can tell we are going to have a bit of a learning curve to climb. Embrace the suck, I guess!
I wonder if this number is still any good? I'll probably need some support to figure this one out!
Channel 1 displays OK. I'm definitely going to have to spend some time with the manual to figure out these controls...
This scope has a limited on-screen menu, and the buttons at the bottom of the CRT bezel allow you to do access more functions than what the knobs on the faceplate allow. Again, this is a new feature I don't know anything about as yet.
At this point I decided to see if the piggyback Tekmate 2104A was going to work. The big fat cable on the right carries data back and forth between the scope and the Tekmate computer. I'm pretty sure this was a proprietary Tektronix data bus called GPIB
Apparently you can piggyback other devices using the pass-through connector. The remaining ISA expansion slots for the 2402A (just above the GPIB connector) are still blanked off, and therefore empty.
I was hoping to find a VGA connector here, but no... The port for an external monitor is blanked as well... so right now, the only graphics output option is through the little CRT screen on the scope, via the GPIB. On the bright side, there's a slot for a 5-pin keyboard. I might try to find an old VGA or EVGA card and see if I can get this thing to output to a legit monitor in 256 colors.
Fingers crossed - here we go. I heard the BIOS beep, and then the floppy drive light came on. This was pretty standard back in the day for an autoexecute file. The instructions would typically first call to access the floppy drive, and attempt to boot the Disk Operating System from there before moving on to the hard drive for boot-up.
The hard drive came to life next, as expected. According to the online literature, this should be a 44MB drive, and the PC should have come with 1MB of RAM - quite a bit for that era. I'll have to see what other options it has besides the hard drive. There is an option for another 1MB of memory.
Away we go! The PC booted up, communicated with the scope over the GPIB interface, and displayed a limited menu that can be operated with the five buttons. The CRT focus has been adjusted in this picture.
I started one of the applications using the pushbuttons. I should have shut off Channel 1 and 2 traces so that the text would display better. Another time...
I can't say that I'm enamored of how this scope displays traces. The traces look notchy compared to an analog scope. They are not very smooth, and they have a tendency to wiggle slightly. It's as if the sampling, conversion and display aren't very consistent. The waveforms are not very pretty, and the unused channel looks downright noisy.
Meh, the guy in the video below explains why digital scopes apparently have more noise than older analog scopes. I guess I can live with it.
Hi,
ReplyDeleteGPIB is not proprietary Tek, but it is basically an open standard by HP, which called it HPIB originally and now known as IEEE-488.
For the display issues, you should get the service manual (available online) and go through the adjustment section. The scope has dynamic focus, so if set properly (there are some additional pots inside) then you should have a much better image. Same goes for the trace noise, do the adjustment of the CCD clock. But read the service manual thoroughly for this, as there are some steps to take. The 2402A takes a special VGA or EGA card which piggibacks on the mainboard, but you should be able to install any 8bit (!) ISA card in it. No 16 bits, so you are limited with what VGA cards you can install.
Hey there,
ReplyDeleteThanks for taking the time to share that information. I very much appreciate that! The 2430 and the 2402 both came with service manuals, which I sadly haven't spent any time reading. Now that I have some insight what to look for, I will revisit this scope and see what I can do with it. Thanks again for stopping by and more importantly for sharing some pretty rare knowledge!
Best wishes,
Mark
I'm glad I could help. One important thing. If you are running the scope with the cover off, you need to use some external fan to cool it, as the case is part of the cooling setup and cold air is sucked in at specific point for the most heat sensitive components, like the CCD array. If the case is off, then just use a table fan or something like this to blow air directly at the board. This warning is in the service manual, but take this seriously as otherwise some circuits may be damaged.
ReplyDeleteOther than this, it's fairly easy to work on the scope and you do not need much specialized instrument for a full calibration.
You can also expect two thing in the future:
1 - the caps in the PSU die at some point, not a big deal to replace.
2 - the NVRAM which holds the settings and calibration data has either an external or an internal battery (depending on serial number) and this will go flat at one point. You'll probably get all kinds of interesting error messages, most likel FPP (front panel processor) fails at startup.
Also, there is a Tektronix Scopes group at https://groups.io/g/TekScopes folks there are genuinely Tektronix Wizard so ask there any question you may have.
Thanks for stopping by again!
ReplyDeleteAdvice, help and encouragement are always appreciated - especially if it keeps me from damaging things. As you say, the caps will be no big deal, I can certainly handle that.
I really need to replace the batteries on both the 2465A and the 2430. I just hope I can keep the NVRAM powered up while I make the swaps. Definitely don't want to mess up that operation...
I'm familiar with the Tekscopes group, and I wish I had more time to learn from them. I'm quite ready to be retired, so that I can spend more time doing what I enjoy, and less doing what it takes to pay the bills, hahaha.
Hi again. For the 2430 don't worry about the battery. The scope can recalibrate itself with very little help. As far as i remember, you'll only need to supply a couple of different voltage levels to the channel and trigger inputs and maybe some square wave to do a full ext. cal. I sold my 2430A some time agon, but it was much easier to calibrate than the 2440 which required some additional (though not hard to create9 signals.
ReplyDeleteSo there is basically no point is trying to maintain the battery voltage as a self cal and ext cal will bring the scope back to specification quickly and easily. The 2465 is an other matter, I'm not familiar with that but afaik it is much worse if you loose the calibration in that.
Well, it's good to know that I don't have to worry about the 2430 - thanks for that info. I may have to worry about the BIOS battery on the motherboard of the Tekmate though. I had one of those go out on a 286 computer a couple of decades ago. Not fun.
ReplyDeleteThe 2465 battery will be a challenge, for sure.