Hooking up a floppy drive after a decade of disuse today, I followed the notch/key on the connector/cable but it turns out to be incorrect! Turns out I should do the opposite, forcing the key to the side without the notch, by force (or trim the key)!
So stick with the conventional wisdom that the ribbon’s pin 1 (marked) should always stay close to the power connector, regardless of whether it’s IDE or FDD (3.5″ or 5.25″), EVEN IF FOOLPROOF MECHANISMS TELLS YOU OTHERWISE!
Over the last year, I got a couple of requests for 54616B that specifically ask for a “vertical output” port at the back. I have never seen an oscilloscope that came with such a port, including a few hundred of first generation first generation 54600s I acquired from many different sources.
I got curious and looked it up. Turns out it’s a secondary feature of a relatively obscure option (only mentioned in the manuals, but I have never seen one) called Option 005, which lets you analyze (like count lines) and trigger over common TV signals, like PAL/NTSC/SECAM, which is way obsolete today. It also seems that none of the customers asking specifically for the “vertical output” port at the back know that it is a super rare option that is normally not included, so they must be using it for something else other than analog TV signal analysis.
A closer look at the user guide shows that “vertical output” port duplicates the signal source (e.g. channel 1) that the scope is triggering on, limited to what is seen by the oscilloscope, to the said “vertical output” port, a secondary feature to let you chain your signal to instruments like spectrum analyzers for further analysis.
I tried the feature myself by chaining the output to another oscilloscope. Even if the waveform is off-screen for the current vertical volts/div, the vertical output port waveform did not clip. I also played around with input impedance settings 1MΩ and 50Ω for a 50Mhz square wave. Based on what gets the square wave badly distorted, I can confirm that the vertical output signal is the analog signal after attenuator (the amplitude changes only with Volts/div that causes relay clicks) but before ADC, assuming a 50Ω load.
Wait! An oscilloscope that duplicates the input analog signals after being processed by the front end (post-attenuator, pre-ADC) to an external output port?! I don’t have to mess with the original signal path by splitting the signal (passively) or make an amplifier to duplicate the signal? Wow! How come it’s not standard (or at least a purchasable option) in modern oscilloscopes? I’d like to see what’s going on with the analog waveform before the scope processes it! Not only it’s very educational, it allows other instruments to get an accurate insight of what the oscilloscope is seeing. Neat!
Installing the Option 005 is not difficult if you happen to have an unobtainium Option 005 case with labels, and the entire kit with all the necessary interconnect. However, it’s like an unicorn and I’ve never seen one. Drilling professional looking holes for it is a nightmare as we don’t have the dimensions. The hardware is also insanely hard to get as it was made for a specialized crowd for the time and practically nobody cared about analog TV signals nowadays. Even if I can get that, they are most often missing the interconnects. The ribbon cable is missing for nearly all of them, and if you get a standard ribbon cable, you’ll realize the plastic retainer gets into the way of a screw on the main acquisition board so the Option 005 card won’t slide in unless you trim some of the plastic off. PITA!
Nowadays I am already spoiled by high end gears like MSO6054A and 13Ghz Infiniiums (like DSO81304A), but none of them has a convenient analog, post-attenuator output like a first generation 54600 with an Option 005. Given the hardware is scarce, I’ll save it for the top of the line first generation 54600 series, namely 54616B and 54616C.
For those who have this special need (need to tap into the pre-ADC signals up to 500Mhz), I can custom build these Option 005 units for you, depending on parts availability. Call me at 949-682-8145 or reach me at my business website www.humgar.com.
I am much more inclined towards Agilent than Tektronix because
EDIT: It’s not just me bitching about how unresponsive the controls (especially the dials) are in their user interface. Dave Jones did a video review of MDO4000 and a bunch of people share the same frustration in the comments section. I thought they improved after TDS1002B (I stopped following their newer scopes), but I was wrong. Still the same poorly thought-out and laggy UI.
There is Lecroy, but there are much fewer old gears in circulation and I don’t like their user interface much either, but at least the dials won’t take more than half a second to respond like Tek. I once asked Lecroy if they can generously share the schematic for an old unit like Agilent and they sent me one. At least they are not being a d**k about it like Tek.
I have both used Agilent and Tek scopes for sale, but my own bench is all Agilent whenever there’s a choice. Tek is OK if you plan out a difficult measurement setup (for documentation or manufacturing), but miserable if you are poking around to troubleshoot (that’s what I use the gears for). I sell Tek just to cater those who have been brainwashed because Tek got the first-mover advantage back in the days.
Of course my bias is based on their Tek’s gears in the digital age. I heard that they were very good at the analog scope times, so that might be the reason why Tek still has a strong following. HP/Agilent/Keysight pretty much nailed the digital techniques. The part I liked about Agilent is that they are generous about making users of their products happy in general, regardless of whether you recently paid them or not. For deeply discontinued products (like 3+ generations ago), they are happy to pass whatever information they have left to help DIY-ers or non-chartered 3rd parties that are willing to service them (like this one, which people are asking for recovery discs for their 1680 series analyzer and the staff went all the way to dig it up from their private stash!) so the company can focus on the newer products.
Support culture aside, Tek’s used gears are so problematic (I learned it first-hand, the hard way) that I’m now hesitant about buying them as investments. It looked like an opportunity because Tek stuff often breaks the same way, so I can buy them cheap, fix them, and resell. But the reality is that the labor is simply not worth it because it’s often not just one problem, but one quickly after another. Now I’m just selling whatever Tek leftovers I have strengthened in the past.
You might think Agilent is sabotaging their own market by taking care of users of their old gears. It isn’t. Whoever that has the budget to buy new will do so. Wobblers between buying new/old gears are not worth agonizing over. The ones who are familiar with the older gears will grow fond of the brand and the user interface/environment they are familiar with and will push their employers to buy Agilent when they get a chance to buy it new. I used to have a customer that I convinced them to get a used Agilent one instead of used Tek, and they ended up loving it so much that they bought a new one from Agilent for their second scope. What goes around, comes around.
I realized throughout the years is that whatever hobbyists do with the old gears and can only help the brand image and build a stronger user base. It’s the user base (engineer’s familiarly) that makes or breaks the deal on new gear purchase. I don’t think big companies that pays good money to buy new will switch to all Tek from Agilent all of a sudden when all engineers are comfortable with Agilent’s stuff, and vice versa.