HP and Tektronix


As is mentioned here occasionally, HP oscilloscopes were never as good as Tektronix and the weak point of HP scopes was the trigger (or to put it another way, Tektronix scopes always had a better trigger). I have been browsing through "The HP Way" by David Packard and I ran into a page about oscilloscopes. First, he talks about an engineer named Howard Vollum who Bill Hewlett met while he was in the Army during WW2, who was interested in building a new type of oscilloscope: "He wanted to design one with a triggered sweep, a concept from radar technology." He talked with Packard but rather than join HP he wanted to start his own company, which HP helped him do by introducing him to their sales representatives. The company he started was Tektronix.

Packard goes on to say that HP should have started building scopes earlier but didn't introduce their first one until 1956 - the model 150, which is the earlier of the two scopes of mine which have the original round HP logo. Packard says it wasn't very reliable. When HP organized their R&D into four divisions in 1957, one of them was just for oscilloscopes. But Packard says they never caught up with Tektronix until they "developed an oscilloscope system managed by a computer some years later" - the digital sampling scope?

I want to add something from an older thread:

Michael F. Coyle wrote re:HP Logo:

"Well, way back when, the HP logo was in "portrait mode" rather than "landscape mode" like it is now.

Somewhere over at work we have a 200C floating around with the original (?) logo.

(Another OT logo question: when did Tektronix switch from the round to the rectangular CRT in their logo? I'm guessing 1970-ish.)

- Michael "

Then I responded:

A question about the different HP logos came up a while ago and I thumbed through "The HP Way" but the only picture of a logo in that book is from a 1967 trade show booth decorated with the portrait mode logo. At one point the HP logo was neither portrait nor landscape mode, it was just a circle not quite enclosing the lower case "hp", the top of the "h" and the bottom of the "p" traveled a good way past the circle. You can see this logo on the HP200A oscillator in the HP Virtual Museum:


At one point HP spun off a company called Dynac to build systems integrated from HP products. The name Dynac was chosen to fit the upside-down HP logo:


The portrait mode logo encloses the circle in a tall rectangle and truncates the excursions of the letters at the perimeter of the circle with the region below the circle solid color and the region above the circle scored horizontally. It gives me the impression of "earth and sky". I have two HP oscilloscopes from the late 50's and early 60's. Both pieces of equipment have only the round logo and the manual for the older scope has it too but the manual for the newer scope has the portrait mode logo on the covers and title page. As it happens, the older scope has a plain round CRT and the newer one has a post-deflection acceleration CRT which blocks the beam from reaching the phosphor at the very top and bottom of the round face, sort of like the portrait mode logo cuts off the tails of the letters. Later oscilloscopes with PDA have rectangular faces. I have always thought that the landscape mode HP logo reflects the change from round to rectangular CRT's on oscilloscopes. For a while the landscape mode logo was blue on the right and black on the left, later it was blue on both sides with the letters still black, and now both sides and the letters are all in a convenient color already in use on the panel. Did HP feel black and blue for awhile? It would seem to have been HP's heyday (70's-80's) but if the logo represents an oscilloscope, HP probably did feel beat up by Tektronix!


I never thought the HP logo had anything to do with 'scopes in any way. I always though they were just abstract designs. Anyway, oscilloscopes never dominated HP the way they did Tek. The usual rule of thumb for test equipment was, "Tek for 'scopes, HP for everything else." (Though Fluke has always made dandy DMM's.)

I think black and blue were just color choices and don't convey any secret message. I suppose they went for the monochromatic logo just to reduce costs a little.

I used to use an HP 175A (ca. early 1960's). It was ECO'd for "improved trigger operation." And behind me right now is a 1741A storage scope. Both work fine; I've never had a problem with triggering or anything else. The price was right on the 1741A -- it's on permanent loan from my employer :)

I wonder why HP never really caught up with Tek in oscilloscopes. Maybe it's because Tek devoted almost all their resourses to oscilloscope R&D, while HP had its finger in so many pies that it could only spend the minimum necessary to stay in the game. (Just a guess on my part.)


I have a 175 also, I paid "real money" ($365) for it at a surplus store (~1983?), it was calibrated and had a manual, two input vertical plugin and delayed sweep generator. Only bad thing about it is that I can't use it in the summer here in Texas - it draws about 800 watts! Also the acoustic energy from its high voltage transformer is in the 40 kHz region and it would activate a TV I had with ultrasonic remote, it would turn on and raise the volume higher and higher! The 150 was being thrown out at TCU where I had worked in the security department and later would hang out, one of the cops brought it to me. The rubber isolators holding the fan had given up but otherwise it was functional. I didn't know till now that it was HP's first scope. In the past year I bought a ton of stuff from an Ebay seller called "AST Electronics" who reduce the price on items till they sell, many of the things I paid $10 for. I got an HP 12?? which must be a competitor for the Tek 5000 series - low frequency, high input sensitivity but just built in a standard configuration, no choice of plugin options. Also a 180 series which might have been HP's answer to the 7000 series - 100 MHz mainframe with plugins up to 18 GHz sampling. I only got 50 MHz plugins with it and the beam is skewed to one side, that'll be fun to look into. And finally, I also got a 1741 for $61. The listing said the storage function didn't work and I figured I'd just have a regular 100 MHz scope but the storage does work and all I can guess is that they didn't notice the little switch that turns storage on and off! It was the single most expensive item I bought from them and it was the only thing damaged in shipment. The box must have rolled over and the unit fell on its face which smashed the knobs for one of the vertical inputs. They cannabalized some knobs and shafts from another unit and sent them to me. What do I need with so many scopes? Good question! This is why I musn't look at Ebay on a regular basis.


The 175 we had at work was pretty neat. It had the delayed sweep plug-in and a 4-channel vertical plug-in. Very handy for debugging logic and such. We had that scope from 1967 to 1983. I think it was the heaviest piece of test equipment I ever used. Worked great, though, once it stopped drifting.

We had the brochure for that scope too. It had a couple of really interesting peripherals. One was a kind of sampling unit that would let you measure the voltage at any point on the display with a DMM. Remember, this is from the mid-60's long before oscillscopes had measurement cursors. The most interesting item was a thermal printer that plugged into the horizontal plug-in socket. It could make a hard copy of any repetitive waveform!

- Michael


I think I've seen the app note - and I think I have the equipment! It's the 3480, you trigger it from the scope's delay generator output - the signal that triggers the main sweep, available on the back - and you use the intensified portion of the delaying sweep to "select" the spot where you want to measure the voltage. I haven't actually done it yet.

The 3480A/B(benchtop/rackmount)have Nixie tubes and the 3480C/D have LEDs. The 3480 is a mainframe with the A/D and the display and there is a slot for an input plugin. I have the 3484 "multifunction" plugin, which makes it like a DMM.

You mentioned the ECO for the 175's trigger - I think I've seen that in the backdating pages in my service manual. It affects the control similar to the holdoff on Tek scopes. What I have had trouble with on my scope is the trigger on the main sweep. Both sweep circuits use a similar trigger based on a tunnel diode. My "bible" in high school was the GE Transistor Manual and it had a chapter on tunnel diodes, plus Radio Shack carried them back then, so I was familiar with them. They have to be biased very critically so a small increase in voltage will make them do their "negative resistance" thing. The circuit in the delayed sweep plugin used smaller currents and a Cermet pot and I never had a problem with it. The one in the mainframe, for the main sweep, used a 20 ohm, 5W rheostat and it just wouldn't stay set. A few years ago I finally replaced it with a 100 ohm multi-turn pot in parallel with a smaller resistor and now its OK. Recently I saw that Radio Shack carried a 20 or 25 ohm rheostat - probably for a speaker attenuator pad - and I was tempted to try it, for the sake of authenticity! - but I resisted.


A mixture of lore told to me by an HP Elder...

Tektronix' "venture capital" came from Dave Packard - he knew or knew of Tek founder's "triggered oscilloscope" idea (based on radar range gate tracking concepts) during WWII. I think this is alluded to in "The HP Way".

In the late 40s and 50s, HP used a distributor channel, i.e. did not sell direct with its own sales force like Agilent does today (this was the pre-computer products era - HP only sold test equipment). That distributor was Norm Neely (those on the US West Coast who have bought from HP might have heard of and been puzzled by the HP US sales pre-90s regions: Eastern Sales, Southern Sales and Midwest Sales and Neely Sales). At that time Norm Neely was also the Tektronix distributor in the US. Thus HP did not need to sell an oscilloscope and Neely didn't want HP to because the Norm's product line already had scopes covered. In fact, HP happily recommended Tek scopes to complement their wares.

At some point in the 50s, Tek decided to both expand product lines into HP's baliwicks and sell through different channels. As always 'scopes were "core test technology" and the loss of Tek hurt Neely badly. It also left a gap in HP's test "solutions". As a result HP acquired Neely's rep company and Norm was the first VP of sales for HP. Shortly after the first HP oscilloscopes came on the market.

My take on this is that HP was pushed into oscilloscopes rather than having made a chosen product extension. Thus many of the HP scopes of yore (until the recent Infinium and Jedi scopes, which started to eat Tek's lunch) were often 2nd fiddle, me-too products behind Tek. The 1980A still makes me twinge with pain.



That goes along with what I have read in "The HP Way" - distributors not wanting competition among their clients but wanting all bases covered, and HP buying out a major distributor of theirs to form their own sales force. Also about HP helping Tek get started.

I guess Packard is being diplomatic when he says, "As time went on it became quite clear that if we were going to offer a complete line of electronic measuring instruments, we needed to fill in the line with our own oscilloscope." But he goes on to acknowledge that HP lagged behind Tek on scopes until they developed "an oscilloscope system managed by a computer", by which I assume he means a digital scope.

Their first scope, the 150, was designed in 1956 (doesn't say when it shipped). I can't find the section where he talks about bringing sales in-house. It's a hard book to use as a reference because it has no index and the chapters aren't chronological (except within themselves). It might be a "zen" book (not that I know what I'm talking about!)

The stuff about oscilloscopes is all on pages 78 and 79.

What do you think of my theory that the HP logo evolved as a reflection of the change from round to rectangular oscilloscope CRTs? In fact, the first change was cutting off the excursions of the tails of the "h" and the "p" just as the first post-deflection acceleration CRTs, still round, limited the beam from hitting the top and bottom of the screen.


In my limited experiences to modern scopes from each maker, the HPs were more intuitive, but the Teks had more capability and weren't UNintuitive.

I don't know the model #s of the scopes, but the HP is a 100MHz digital storage scope, which is almost completely menu driven. For every button you press or knob you turn, something tells you on the screen what you're doing.

The Tek assumes you know a few things, and if you do, you will do just fine.



I hope some Brits will correct me if I misapply a term I have heard Arkwright the shopkeeper use - You don't know you're born! I'm talking about real ANALOG sopes - scopes that don't tell you anything you can't interpolate from some little hash marks on the screen! Scopes with knobs that turn switches that select real components, not an optical encoder that tells a microprocessor to tell a D/A to pump out a little more current!

Actually, I do have one HP digital scope that I also bought on Ebay a few years ago, model 54200D. I had used a better digital scope at work - my company went from Tek analog scopes to HP digital scopes, so maybe Dave Packard was right when he said HP finally caught up with Tek. My scope is only 50 MHZ (200 MS/s) but what really caught my attention is that it has a digital trigger like a logic analyzer (it is based on the same boards as a 1630 logic analyzer, which can also be configured with oscilloscope channels). I was always kludging up a digital trigger from available gates when troubleshooting with just a scope and I always meant to build a box with some PALs and DIP switches to make a general purpose digital scope trigger, and here was a scope with all that built in! The possibility of hooking this scope up to a computer is what got me started learning about HPIB (only about twenty years too late!)

One thing about my scope that HP corrected on the next family - it has no knobs, only buttons which can be a pain when moving through a thousand choices. HP used rotary optical encoders with spinner knobs on later models.

I've never used a Tek digital scope but at one time we had a 300 MHz Tek analog scope that had intelligence inside to draw labels and even help menus on the CRT.

I have to mention my absolute final HP scope-like device. I asked about it here once but got no reply. In time I did find manuals for it and it is a real doozy! I paid $10 for it but because it weighs 70 lbs (not more than the 175 but I bought that locally), it required my purchases to be sent by freight. It is the 5480 signal analyzer (ca. 1968). The introduction says it is " ... best described as an oscilloscope for looking at signals that are buried in noise." That description plus a switch on the front panel labeled "Histogram - Time or Frequency domain" makes it sound like an FFT analyzer but it's not that powerful although it does contain a simple computer. It uses A/D conversion and magnetic core memory to calculate an average from up to 2^19 instances of a repetetive (but not necessarily periodic) signal. It is possible to set it to run unattended for 10^9 seconds (31.8 years!) It has a light to tell you if the power has failed, which stops the operation but since it has core memory, you can restart it and it will go on from where it left off. The vertical bandwidth is only 50 kHz but "can be extended using a sampling oscilloscope". It has connectors on the back to hook it up to an HP 211x computer. I haven't opened it up or plugged it in yet, but I expect it to look a lot like a 9100 inside.


an ANALOG scope and an HP-34C and you are walking on a cloud, man. Those are real tools from when the world made sense.

I got involved when the Tek 475 was king, and those run good as long as the contacts dont get dirty. I rapidly
migrated to things like 2236 (the cheap flavors that cost far less than the 2465B). They'd be like 60 MHz or 100 MHz.

Finally got a 2465B but I still need probes for it.

Was able to get an official blue scope-cart from eBay so I can wheel it around in the livingroom.


The very slender cart with a single support - the "scope-mobile"? Gorgeous!

I got one of the rather square Tek carts with four supports made of tubular metal from a guy on Ebay who sold me a 5000 series scope. Worst shipper I have run into, although luck came through in the end. First the scope arrived with a little tear in the outer kraft paper wrapping. Something narrow about 3 inches across - I can only imagine a forklift blade - had punctured both layers of metal on the back of the chassis. Miraculously, nothing functional was damaged but the trace rotation pot. The scope was wrapped in a garbage bag then packed in a diaper box barely larger than the chassis with a few loose foam pellets. Now I understand HP's packing instructions, especially the inner box! The procedure for making a USPS claim seemed daunting so I decided to keep it for it's interesting story. Before the scope arrived, he had sold me the cart and I had sent payment. It took months to arrive, he had a bunch of excuses. The box it came in had broken open but luckily none of the parts had fallen out, even though the very heavy casters were loose in the box and could easily have fallen out. After it was all over, I wrote him that if I were him, I wouldn't brag about "never a handling charge"!


you let the shipper off too easy

I would have told the guy
"refund me a $20 credit for the damage, OR I leave
negative feedback that says you dont package the merchandise adequately".



Not to put too fine a point on it, but isn't that extortion?

If it were me, I'd either go for an exchange (if it's a commonly available unit) or just leave negative feedback. Packing like that is really inexcusable.

- Michael


I don't think this guy cared much about feedback. There wasn't any option of an exchange and the unit was working, even with the hole in the back. The guy told me to go through the post office for an insurance claim, I called them about it but it sounded like a lot of trouble for not much return.

I had a funny feeling about the guy from a pre-auction email - he seemed a little belligerent - I thought maybe he was an immigrant for some reason (he had a German name). Once I committed myself by bidding I decided to see it through.

I kind of like the "story quality" of the hole in the unit - it's quite spectacular, especially considering it missed everything critical! - and also, I found a couple of nice, old Tek scope probes stuffed behind the drawer of the cart! That's sort of a refund.

I have asked for and received refunds before, two times from new Ebay sellers who wanted feedback more than cashflow. One was my HP67 that had been savaged, the seller refunded about 20% (I think I had suggested the amount) and the other was an inexpensive TI calculator that was in fine shape except the battery door latches were broken so it wouldn't stay closed with the cells in place, I'm pretty sure the seller did it - I asked if he noticed the problem when he tested the unit, he said he tested it with a bench supply. He refunded all my money and told me to keep the calculator. Then there was my HP1741 scope with smashed knobs, at first the seller wanted me to make a claim with the freight company. In my opinion, it was another case of insufficient packing, I asked the seller if they couldn't send me some knobs from another unit (this seller had TONS of equipment) and they agreed, sent me the whole switch assembly! And finally, I got an HP97 with a broken key from a pretty active seller. I was able to do a little research which included a 97 that was sold with broken keys on Ebay, suggested a refund for the difference - which I said I would be willing to take as a credit toward another of their auctions (they had a lot of interesting items!) and they agreed.

I've never left negative feedback but I have composed some. Once I got an HP9825A from a seller in Quebec. They said it wasn't working, they didn't know why, and it was in good shape otherwise. The photos didn't show the right side of the unit. I was new to the 9825 at the time but they weren't - I later found that they had auctioned working units before and after mine. My unit was missing the OS ROM cartridge that plugs in on the right side, which they must have realized. In my innocence, I told them the ROM was missing and gave them a description and asked if they had seen it lying around - they ignored my emails. I was going to post this with negative feedback: "Watch out for dese French-ies! Dey is cheat-hers!" only in all caps. I never did, though. I was able to get a ROM from another seller, I think I paid $35 for it.

I think experiences like this set an upper bound on how much business Ebay will be able to do: their success depends on their sellers and a certain proportion of them are ignorant about how to pack things for shipment and have no concept of customer service. One quickly learns that the only way to come out ahead on Ebay is to pay a very low price. Otherwise one gets tired of the aggravation and quits looking at the auctions - that's where I am, I only look when people point things out here in the Forum!


The Tek '475 is still king... a better general purpose analog scope cannot be found. Although it is rated for 200-250MHz, I have used it to align 550MHz UHF transmitters.

I bought a lot of 4 "dead" ones on Ebay for around $200. The problem was the voltage selector was set for 220V.


can't say anymore


It's hard to grouse about Tek 475, seeing how I got one downstairs.

Main thing is just they are getting old.
The contacts and the pots keep getting noisy.

I had to replace a dry electrolytic cap in mine,
to keep it running.

The 200 MHz is nice.

Most people would prefer a 2465B (400MHz) though
their inner complexity is frightful.

I always preferred the cost/value pinnacle of the
2236 (if i got the model right) the one with
100MHz bandwidth, and a nice clean looking
portable front-panel. There is less 'noisy
connection' behavior from the front-panel pots
and switches in comparison to 475. You can also
get it with a nicely integrated voltmeter/counter
that doesn't put a big hump on the top (2236B ?)

To this day, they should be making more 'mini's'
like the size of a carton of cigarettes.
And they should stick with the analog CRT.
But nooooooo they had to discontinue all the
good stuff, and sell stuff thats pretty nearly

Carly is also working part-time at Tek. So all they
sell now is chinsy plastic digital junk. So, I don't buy it !!

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