Fig 16 shows the falling-edge transition time as just a bit below 1 picosecond, with a "p". Other figs suggest maybe 300 ps. The numbers are probably 20-80%, which improves the rise time considerably, for free. My flop would be closer to 100 ps, measured 20-80.
That data sheet doesn't make a ton of sense.
One thing that makes electronic design even more interesting is that data sheets are often wrong.
We use the FIN1101 (lvds-lvds buffer) as a 1 ns RRI comparator. 85 cents. LVDS is great stuff.
--
John Larkin Highland Technology, Inc
lunatic fringe electronics
Unfortunately this kind of pricing doesn't apply in Australia. Any good 2nd hand equipment asks silly prices, and US Ebay sellers won't ship to Australia. I have an OR-based reshipper, but the cost to ship something like this is still pretty high.
Gerhard chose his words well when he said 6V was "still legal". Make sure you don't turn up the supply rail too high and forget the source termination resistor or it might become all export-controlled as 3A230. So, if you figure out how to do that without it failing, for goodness sake don't tell me. Likewise if I do it then I will also make sure that I don't tell you how.
I wonder whether that is a part of the reason why the datasheet max VCC for a lot of logic parts is 6V or so - (as well as the gate length of the transistors). Imagine the paperwork if it was specified a bit higher.
I'm the new owner of that EBay 11802, and they even gave me a partial refun d on shipping since I'm in the SF Bay Area. It was exactly as described by the vendor and came very well packed.
As suspected, the battery backed RAM had a dead battery, and two chips from Digikey solved that issue. It now passes all the self-test and extended di agnostics.
It does seem to have another problem, which I'm researching. It seems to no t trigger on any external sources. I also had picked up a SD-22 head for $1
85, and if I set it to internal triggering, and feed it a half volt square wave, I get some unstable traces at about the right voltage, and I'm assumi ng they are unstable due to no trigger sync. It does seem like this suggest s the SD-22 samples (and even has a 2014 calibration sticker). The enhanced accuracy calibration also fails because it says it didn't trigger. So clos e, not quite there yet.
The trigger problem seem to be neither external nor either delay line trigg ers work. The calibrator output also seems stuck at a small negative voltag e, and the internal clock output seems similar.
My current plan is to check some things with a scope, like the the TB card clock and some of the strobe board outputs (as soon as a SMB to BNC adapter comes). It offhand seems like the clock must work, as internal triggering works. I see there is also a trigger selector board which perhaps has an is sue. Looking at the block diagram, it seems like there are not that many pl aces that could cause no calibrator and internal clock output, assuming the internal clock really works. Assuming there are no unobtainium parts invol ved, it may be debuggable down to the chip level.
It also had a non-functioning upper dial, which on taking out the two screw s for the screen bezel, found a little shaft extension from the upper encod er to the knob that was cracked. I put a little super glue on it and heat s hrunk some tubing to restore the squeeze on the end that grips the encoder shaft and it's happy again. Two of the quarter turn fasteners on the top co ver are also missing, but whatever.
The screen seems clear (monochome) all the buttons seem to work, the "touch " screen works fine, and takes a bit of getting used. No smoke or horrible fan noises. Don't see any critters living in it or any sign there ever were . What's with that Tektronix document about washing you scope with spray wa ter. Making it all squeaky clean would be nice though. I also do have a ult rasonic cleaner and some Branson EC, although the TB board is huge and doub t it fits in the tank.
I do have the 11801C lame service manual that's around, which does at least have some block diagrams with look very similar to my 11802. It was certai nly exciting that $25 in battery ram chips fixed all the diagnostic errors, but also a bit of a bummer that something else, perhaps not so easy to fin d and fix is wrong too.
It is just amazing to turn that horizontal timebase knob and see the scale go down to 1ps/div, so feel quite motivated to do some serious debugging. I built one of the those Jim WIlliam style avalanche pulse generators, and m y 300 Mhz Rigol MSO2302A scope (which I like quite a bit) can't come close to measuring the rise time.
This series of scopes also has software running in an environment called Sm alltalk, and I just happened to have worked on Smalltalk virtual machine im plementations at a Xerox PARC startups offshoot, that disabled debug button is like candy on the other side of a window to me.
I see some messages here that 11802 10.x firmware was imaged. Does anybody know if it's downloadable someplace? This one has the 9.x firmware, so I re ad would not work correctly with a SD-14 head without new firmware.
I'm new at resurrecting old test equipment, so it's a fun challenge current ly. Would be a bit more fun if Tek had released some real service manuals.
Tek also produced some Smalltalk workstations in the mid 80s; it was the second Smalltalk implementation I used, Apple's being the first.
Back then it was fun to see how quickly electronic engineers jumped to embed Smalltalk (HP did it too). Doubly so when considering the shenanigans that softies went through to re-cast their procedural code in a very poor version of OOP (anybody unfortunate enough to remember JSP?).
I presume you know about the Yahoo TekScopes group.
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