EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: JM1366 on December 14, 2022, 10:21:21 pm
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Horrible waste of time, but I need some entertainment.
I think we can agree that most of what HP and Tektronix sold was pretty good kit, but this is a place to talk and laugh about the things that should never have made it to market.
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I think the 491 makes the list of Tek dogs, though I've never actually seen one in operational condition (I have seen a few dead ones though).
From the Tekwiki:
"Due to severe performance limitations, the 491 was replaced by the completely redesigned 492 in 1980."
Ouch. Double ouch if you spent the equivalent of $40,000 one one back in the late 70s.
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I nominate my TDS460.... a 400Mhz analog Front end with a 100Ms/s Digital backend... but at least they have the "ET" mode.
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HP 3458A, which is both the best and the worst high-end DMM that they made. When you get a good one it has outstanding performance but if you get a bad one it has really terrible drift in the ADC.
What is worse HP/Agilent apparently hadn't got round to fixing the problem in the design even after 25 years from the product's introduction. I am sure that state of affairs would not have been allowed to persist if Bill and Dave were still around.
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I'll restrict my nominees to pre-1995 stuff because that is mostly what I have:
For HP, they had a period where they decided to compete in the low-end market. For example, the 3435A, 3465A and 3466A are 3-1/2 or 4-1/2 digit DMMs that are cheaply built and not worthy of HP's state-of-the-art reputation. Similarly, the 5300A and 5300B are "mainframes" that accept a variety of plug-ins, mostly counters. Again, they are low-end stuff and if you want a counter, then buy a real one. The HP (Germany) 811x pulse and function generators are very nice - when they work. Almost everyone I see offered on eBay is throwing errors indicative of faulty HP-custom ICs that are, of course, unobtainable. Finally, you would think when HP developed their 6-1/2 digit DMM HP 3457A, it would be better than the preceding 3455A and 3456A. But I find the 3457A slow, noisy, hard to see the LCD display, and generally a "dog."
For Tektronix, their stuff seems electrically excellent. But mechanically, that is another story. Repair and maintenance of some of their earlier scopes (the 7000 series or the 22xx/24xx series) is a chore. Cam switches, endless brackets and screws, stuff packed into the chassis like sardines, etc. And I am not a big fan of the 500-series mainframe and plug-ins. Although I suppose it is nice to have a 6-bay mainframe packed with a variety of plug-ins, I find the individual plug-ins to be somewhat lacking in performance and I would rather use a dedicated piece.
Just my opinion...
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For HP, they had a period where they decided to compete in the low-end market. For example, the 3435A, 3465A and 3466A are 3-1/2 or 4-1/2 digit DMMs that are cheaply built and not worthy of HP's state-of-the-art reputation.
I agree on your other calls, but am very surprised to see the 3466A on the list. I bought mine new in 1981 ($995 !!), it went back for a warranty repair 9 months later, and has worked flawlessly ever since. It has been my go-to daily driver DVM for decades - still is. Have not even had to tweak the cal adjustments or clean the switches. Excellent 100kHz+ TRMS converter. Very useful 20mV/20Ω FS ranges. Real 1200V DC max input rating. Fast autoranging. Nice big LED's. What's not to like...
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I’ll second the Tek 2245/6/7 series. While they are decent scopes when functional, service is an absolute bitch, especially the main board on the bottom. Good luck extracting it to do any required work.
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I’ll second the Tek 2245/6/7 series. While they are decent scopes when functional, service is an absolute bitch, especially the main board on the bottom. Good luck extracting it to do any required work.
I agree, I have repaired several 2246 in the past, repairing the mainboard is a PITA when the board has to be extracted. Even the CRT must removed to get out the board. I really like older Tektronix stuff, but most of these instruments were never easy repair because of their mechanical construction.
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The usual low hanging fruit with HP would be the 16500 Logic Analyzer. Featuring that crap "touch" screen using a IR sensor grid. And then only featuring a single rotary knob for its user interface aside from that.
HP must have sold a keyboard two weeks after each sale of a 16500. :-DD
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I don't care if the Tek 491 is a design fail or something, it's a solid 10 out of 10 for the looks and I would adopt that boat anchor anytime if I found one for (relatively) cheap. And bonus points for the repair challenge if it's actually not working at all. :-+
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The Tektronix 650 series Picture Monitors were seriously dire.
The Tek 520 Vectorscope was OK when it worked, but when it got a bit old, it was a nightmare to work on.
The RM529 Waveform Monitor was good when it was new, but was compact & full of tubes, which was a poor combination when it came to reliability.
Add this to fairly short lived CRTs, there is little wonder why we sighed with relief when the 1481R came out.
HP?
I always found their 'scopes a bit more "fiddly" to use, though I quite liked the 180 series.
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Tektronix 2710, 2712 portable Spectrum Analyzers, horrible membranes panel, bad interfaces design, easy to blow out inputs mixer
Jon
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The usual low hanging fruit with HP would be the 16500 Logic Analyzer. Featuring that crap "touch" screen using a IR sensor grid. And then only featuring a single rotary knob for its user interface aside from that.
HP must have sold a keyboard two weeks after each sale of a 16500. :-DD
:-DD :-DD :-DD
I liked the 16500C. The system still drove like their earlier products. It was that last system I looked at from Keysight that looked like they had fired all their software engineers, hired all new managers with bright new ideas how things should work and never even knew what the product did. It looked like softheads were the targeted users.
For Tek, that 78nn DSO. Nice when it would stay running but more down time than up time.
For HP, I can't think of anything. May explain why most of my home is fitted with HP.
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Can we include the HP name changes? ;D
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The HP (Germany) 811x pulse and function generators are very nice - when they work.
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I bought a couple 8011A pulse generators with the counter options for a specific project. I also have an 8010A dual-channel pulse generator. Both are from HP Boblingen in Germany. While they are constructed quite differently from each other, they are each assembled very strangely. The 8011A style is troublesome to work on and the user interface is one of the worst. Completely unusable without actually monitoring the output with an oscilloscope. The 8010A is actually somewhat elegant, except that all the connections between the many circuit boards are through harnesses that use silver-plated contacts to gold-plated pins. The silver tarnishes to black and basically disconnects.
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Keysight EXR/MRX: loud like jumbo jet.
They replace power supply with fanless in service center as modification of product. But it is still to loud for me. If I compare with S series.
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Handheld products, like DMM's. OLED problems and other fails. It is not good for brand like Keysight.
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Tek: TDS540. Somebody went and bought a truckload of crappy capacitors to make these. It cost a fortune in 1991 new, from memory about 35k. Noisy front ends. No schematic then, but I think you can get one now. Can be restored to life by changing all of the capacitors, 100s of them.
2246: Unreliable power supply, but otherwise good, full of unobtainable hybrids.
Keithley (Tek now). 2450 SMU. Very expensive piece of kit, crashes all the time, never writes the error to the log. Tek tech support always asks what’s in the Log. Firmware updated, no difference. Too new to be this bad.
Tek: DPO5034. UI from hell, changing from Auto trigger to normal needs a mouse. Touch screen alignment only so-so. Otherwise a very good scope.
HP35670A Dynamic Signal Analyser, the soft keys up the right side of the screen fail. My employer has half a dozen of these, all have the same fault. I’m not sure how they built it, but suspect the sealed soft key strip was jigged in space and the rest of the instrument built around it.
[edit] HP1650. Forgot this, expensive (16k), 1000 samples deep, for the time a sort of functional logic analyser. Used a proprietary floppy format, and none of the original disks will now boot. If they would I could make another boot disk. Not PC compatible in any way. Not worth the effort, and the UI from hell.
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Handheld products, like DMM's. OLED problems and other fails. It is not good for brand like Keysight.
Couldn't agree more, with this. I have several HPAK handhelds, and the only one I like wasn't even made by them, but by Escort (U1401B).
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HP 8112A/8116A: No PLL locked instruments build around unreliable ASICs by German design team, which sucked.
HP 8082A: Same garbage as 8112A/8116A, but with added suckiness with sliding switches, that destroy the PCB contact traces over time.
HP 8656A/8657A: Cheap design, construction and poor performance, slightly better on HP 8657B....
Forgot: HP3457A: Display sucks, cheap plastics, bad keyboard, stupid preamp/attenuator design and +/- 3V full range ADC that gives a noisy instrument.
HP3458A: Soooo much fun, if you have failed U180 ;-D
Tek: 7L13, 7L14: Fricking spectrum analyzer that is squeezed into 3 plugin compartments, with no regards to serviceability whatsoever...
Anything with storage tube nowadays, was the only technology back then, but totally outdated nowadays and a pain to use
Their CCD based ADC, 2kPts DSOs, not great released, equally outdated nowadays as deep memory is about the only reason why I would use a DSO over a classic CRO (Tek 7000)
Keithley: Poor plastic quality on their old, brown instruments.....
Classic Fluke: Most structural parts are made from cheap plastics that fall apart, over time (8505A/8506A, Fluke 5440B...)
And their stupid delete/substitute options!!!
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HP 8112A/8116A: No PLL locked instruments build around unreliable ASICs by German design team, which sucked.
HP 8082A: Same garbage as 8112A/8116A, but with added suckiness with sliding switches, that destroy the PCB contact traces over time.
One of those was to replace the hp3325. We used lots of 3325 back in the day and needed another, hp rep told us about the "new" replacement, so we ordered it. Turns out we didn't actually use it until a year later and discovered the output waveform was horrible (lots of HD, spurs, and Phase Noise). Sent in for repair only to find it was ok and were told "ours was better than most" :wtf: So contacted rep for return, he indicated that we couldn't return it because of the length of time since receiving, even tho we explained we never got to use it.....didn't matter hp policy was policy so we were stuck.
We ordered a Stanford Research function generator and stuck the HP on the self never to be used. Later we got a call from the HP rep asking about an order for ~$1/2M (MW Gen, SA, VNA and such) that was in the pipeline, we told him that we had placed a "hold" on the order and were evaluating some R&S equipment. A couple days later he showed up with a new hp3325 for no charge ::)
Mind that we were at a large international technology company that purchased ~$50M/yr from HP and Tek alone, so somehow the rep found a way to "bend" the hp company policy ;)
Anyway, that "new" hp generator was a total PoS, absolutely worthless for our needs, and how this was allowed to become an hp product is still unknown to us :P
Best,
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I have a couple of the HP 811x function generators, one has the traditional bad custom chip, the other works and is all calibrated. The output is most certainly not impressive at all, and without any form of accurate frequency reference internal or external, I have no intention of using it... I'll keep to my 3325A thanks.... The 811x squarewave output is more of a bad sinewave for a concerning portion of it's output range.....
I do like the Tek TM500/5000 series modules though. I don't bother with the toy multimeters or frequency counters, they don't have nearly enough resolution for my taste, but the calibration oriented modules are great IMO (SG503, SG504, PG506, SG5030, etc)
I just wish the plastic corners on the front panels weren't so brittle and prone to cracking.
On the earlier units, the front plastic was held in place by countersunk screws at each corner under the aluminium faceplate. Not a good idea to put outward pressure near the edge where it gets knocked a lot, cracks are rampant...
Later models changed the design which improved things, and larger later units used aluminium in place of the plastic which is the best solution IMO.
I'll be getting a replacement plate for my SG504 machined in aluminium as part of its restoration. No more cracks! :)
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I’ll second the Tek 2245/6/7 series. While they are decent scopes when functional, service is an absolute bitch, especially the main board on the bottom. Good luck extracting it to do any required work.
I would offer a counterpoint on this - the Tek 2245/6/7 are far easier to live with than the venerable 2465/7 due to not using the real PITA in Tek scopes - the infamous Dallas chip and leaking tantalum caps. My 2247A's are a joy to use They are keepers for general AF work and especially for monitoring RF modulation. That well-honed, excellent UI - including the adjustable orange graticule - is very tough to beat. Mine have been working for years without complaint.
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I'll go even one more step back to my 2235. I just calibrated it and it works great. Super simple to use and after the usual service upgrades, it's rock solid.
I'll be eventually selling off all my 24xx series scopes and keeping this 2235. No weird chips or RAM backup batteries or complicated functions, just a few dials on the front and a nice sharp trace. :)
Oh, talking about crappy scopes, the Tek TDS694C..... Due to manufacturing 'reasons', the trigger chips often aren't thermally bonded to the PCB so well, and Tek neglected to install heat sinks, so these unobtainium chips that run reaalll hot tend to die.
Luckily, the seldom used 'Other' (or External) trigger chip can be taken out and swapped with the faulty chip if one doesn't mind the small loss in functionality.
A shitty failure point for a screamer of an early 2000's 3GHz, 10GS/s scope, all for the want of a little heat sink...
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How about the Hp 8165 "Signal Source"
They did not even call it a function generator.
I have two, if anyone is interested.
Just weird combination of different technologies including Emitter Logic....Capacitor discharge, crystal generator and on and on
A real dream (a bad one) to work on.
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How about the Hp 8165 "Signal Source"
They did not even call it a function generator.....
Similar garbage like all instruments from the HP 80xx and 81xx series from Germany.
Unlike 8112/8116, this one is phase locked at higher frequencies, but with horrible phase noise
And with some kind of DDS below something 1kHz or 10kHz or something.
Microprocessor is stuck at some kind limbo, if battery fails, then you have to set every fricking control parameter on the front panel, before it comes back to life again.
And it's a huge box with very little electronics inside and of course lots of custom chips that fry and make repairing it a miserable experience.
Had 2x 8165A, 2x 8116A, 1x 8112A and 2 8082A some years ago, swapped parts to make most of them work again and then sold all the shit.
One of the few great HP pulse generators is HP 5359A, fully synthesized, designed in USA and without parts that fail for no good reason.
There are real, great, beautiful HP instruments, like HP3456A, HP3325A, 3326A, 3335A, HP8566/8568, HP856x, 3585(A)B, HP8662/8663A, E3615/6/7.....
Instruments that are fun to work with and a beauty to look on.
And there is 80xx/81xx series garbage, sell it on ebay for good money while it works, so other people can get rid of the trash, when it breaks again.
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I'll go even one more step back to my 2235. I just calibrated it and it works great. Super simple to use and after the usual service upgrades, it's rock solid.
I'll be eventually selling off all my 24xx series scopes and keeping this 2235. No weird chips or RAM backup batteries or complicated functions, just a few dials on the front and a nice sharp trace. :)
Oh, talking about crappy scopes, the Tek TDS694C..... Due to manufacturing 'reasons', the trigger chips often aren't thermally bonded to the PCB so well, and Tek neglected to install heat sinks, so these unobtainium chips that run reaalll hot tend to die.
Luckily, the seldom used 'Other' (or External) trigger chip can be taken out and swapped with the faulty chip if one doesn't mind the small loss in functionality.
A shitty failure point for a screamer of an early 2000's 3GHz, 10GS/s scope, all for the want of a little heat sink...
Which ones are the trigger chips you are referring to and where on the board on the TDS694C, I don't have any schematics for the one I have. Any information would be helpfull.
TIA
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There's some info here at Tekwiki:
https://w140.com/tekwiki/wiki/TDS694C
I don't have one of these scopes so I can't provide more info (My fastest scope is a currently a TDS794D)
If you have one of these scopes, I recommend installing some heatsinks on the trigger chips with some thermal epoxy before they fail...
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I think the 491 makes the list of Tek dogs, though I've never actually seen one in operational condition (I have seen a few dead ones though).
From the Tekwiki:
"Due to severe performance limitations, the 491 was replaced by the completely redesigned 492 in 1980."
Ouch. Double ouch if you spent the equivalent of $40,000 one one back in the late 70s.
I wonder if that “severe performance limitations” description is really fair. It was on the market for 14 years, so I can’t imagine it was that bad.
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the precision power supply from HP (6000 series) has the absolute worst switch ever.
I mean the one you dial up with the buttons that everyone was raving about. Great supply, but that switch bank is just awful awful awful.
And they don't put flanges on anything, its just a bunch of crap sandwiched together like a garage door.
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I would also nominate the TDS3xx/4xx series. They were obviously a sort of learning phase in regard to user interfaces for Tek which was nevertheless foisted on the customers.
And the 250MHz pulse generators from the TM500 series - I have yet to encounter a working one.
For HP, there is the 6177B current source. No matter how often you read through those changes, mine (defective) does still not match any of them.
the alignmrent procedure for the HP6825 Bipolar Power Supply was conceived by a sadistic maniac.
And then there is the HP5334A universal counter (a capable and nice devive by itself), which, contrary to any other HP device I've seen, does not simply take the HP10881 OCXO, but needs a special adaptor board, which is pure unobtainium.
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the precision power supply from HP (6000 series) has the absolute worst switch ever.
I mean the one you dial up with the buttons that everyone was raving about. Great supply, but that switch bank is just awful awful awful.
And they don't put flanges on anything, its just a bunch of crap sandwiched together like a garage door.
Wait until you get a feel of the similar switches on the even more expensive R&S NGRU. Those of the HP6114A feel sturdy and crisp in comparison. and you can't exchange them for better ones, as they contain the divider resistors too.
:rant:
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I would also nominate the TDS3xx/4xx series. They were obviously a sort of learning phase in regard to user interfaces for Tek which was nevertheless foisted on the customers.
And the 250MHz pulse generators from the TM500 series - I have yet to encounter a working one.
Yeah, I took a look at the TDS3xx /4xx series, but why bother when you can select from the TDS5xx/6xx/7xx series... (besides physical size). Much nicer displays too.
Do you mean the PG502 or PG505 pulse generator? I have a PG502 that works and is adjusted nicely.
And then there is the HP5334A universal counter (a capable and nice devive by itself), which, contrary to any other HP device I've seen, does not simply take the HP10881 OCXO, but needs a special adaptor board, which is pure unobtainium.
Would a replica via a Chinese PCB manufacturer be feasible?
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the precision power supply from HP (6000 series) has the absolute worst switch ever.
I mean the one you dial up with the buttons that everyone was raving about. Great supply, but that switch bank is just awful awful awful.
And they don't put flanges on anything, its just a bunch of crap sandwiched together like a garage door.
Wait until you get a feel of the similar switches on the even more expensive R&S NGRU. Those of the HP6114A feel sturdy and crisp in comparison. and you can't exchange them for better ones, as they contain the divider resistors too.
:rant:
lol with stuff like that I just want to put a cable that sticks out of the instrument and a control panel for it like one of those industrial crane control things
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I would also nominate the TDS3xx/4xx series. They were obviously a sort of learning phase in regard to user interfaces for Tek which was nevertheless foisted on the customers.
And the 250MHz pulse generators from the TM500 series - I have yet to encounter a working one.
Yeah, I took a look at the TDS3xx /4xx series, but why bother when you can select from the TDS5xx/6xx/7xx series... (besides physical size). Much nicer displays too.
Why bother with those when you can get a TDS3xxx/5xxx/7xxx?
Do you mean the PG502 or PG505 pulse generator? I have a PG502 that works and is adjusted nicely.
There was absolutely no need to rub that in further!
:box:
And then there is the HP5334A universal counter (a capable and nice devive by itself), which, contrary to any other HP device I've seen, does not simply take the HP10881 OCXO, but needs a special adaptor board, which is pure unobtainium.
Would a replica via a Chinese PCB manufacturer be feasible?
Oh noe! The Chinese will hide secret jitter-enhancing elements in the PCB and further compromise my timebase!
:scared:
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the precision power supply from HP (6000 series) has the absolute worst switch ever.
I mean the one you dial up with the buttons that everyone was raving about. Great supply, but that switch bank is just awful awful awful.
Why do you think it's awful? Ergonomics? Reliability? I have no problems adjusting the 6114A. I use it side by side with a similar Lambda LR-613DM precision power supply which has a rotary knob per decade, and I find both equally convenient to use.
I do hate the controls of the IET VI-700 voltage / current source. Those thumbwheels are painful to the fingers and I do not enjoy repeatedly adjusting it. I guess the instrument was not made to be adjusted frequently.
And the 250MHz pulse generators from the TM500 series - I have yet to encounter a working one.
How large and (un)biased is your sample group? I also have a PG502 that has been working fine since I got it, so I'm questioning if this is a design flaw.
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I would also nominate the TDS3xx/4xx series. They were obviously a sort of learning phase in regard to user interfaces for Tek which was nevertheless foisted on the customers.
And the 250MHz pulse generators from the TM500 series - I have yet to encounter a working one.
Yeah, I took a look at the TDS3xx /4xx series, but why bother when you can select from the TDS5xx/6xx/7xx series... (besides physical size). Much nicer displays too.
Why bother with those when you can get a TDS3xxx/5xxx/7xxx?
Working on it.... I have my eye on a TDS7xxx series as soon as I sell off some gear to raise funds. :-BROKE
Do you mean the PG502 or PG505 pulse generator? I have a PG502 that works and is adjusted nicely.
There was absolutely no need to rub that in further!
:box:
As per above, wanna buy my PG502? :-DD (for real though, it's on the 'to be sold' pile)
And then there is the HP5334A universal counter (a capable and nice devive by itself), which, contrary to any other HP device I've seen, does not simply take the HP10881 OCXO, but needs a special adaptor board, which is pure unobtainium.
Would a replica via a Chinese PCB manufacturer be feasible?
Oh noe! The Chinese will hide secret jitter-enhancing elements in the PCB and further compromise my timebase!
:scared:
:-DD
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the precision power supply from HP (6000 series) has the absolute worst switch ever.
I mean the one you dial up with the buttons that everyone was raving about. Great supply, but that switch bank is just awful awful awful.
Why do you think it's awful? Ergonomics? Reliability? I have no problems adjusting the 6114A. I use it side by side with a similar Lambda LR-613DM precision power supply which has a rotary knob per decade, and I find both equally convenient to use.
I do hate the controls of the IET VI-700 voltage / current source. Those thumbwheels are painful to the fingers and I do not enjoy repeatedly adjusting it. I guess the instrument was not made to be adjusted frequently.
And the 250MHz pulse generators from the TM500 series - I have yet to encounter a working one.
How large and (un)biased is your sample group? I also have a PG502 that has been working fine since I got it, so I'm questioning if this is a design flaw.
its a piece of shit non serviceable complex mechanism that needs service. Not even snap hinges, but molten pins. And its all soldered down at right angles to a PCB edge pads in a 'creative' assembly method. And its all plastic in there too. Every time someone solders right angle PCB to each other a la stone hedge, electronics god cries
I think that power supply switch spurred dac design because some engineer figured he can make a precision switch matrix without moving parts, and the first good DAC was made in a alcohol fueled haze of insanity entered post failed 6114A service attempt. The engi just knew deep down that management would never allow for the correct amount of mechanical hardware to make that mechanism not suck, so it was improvised, and a semiconductor fab was hijacked and made the first processor controlled precision power supply control chip. Without the 6114A, it would look like the first Alien movie by the year 2170, because they figured out switches.
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Some people won't agree with this, but if you've gone over one, then you know.
HP 8640B.
The supposedly ultra-stable low-phase noise design suffers plenty from short-sided design choices when it's working. Let's start with the supposed phase noise claim. That phase noise is only available if:
1. You're locked to a 5 MHz ultra-stable source (and remember, using basic logic circuits to "divide down" a 10 MHz source induces what? Phase noise.)
2. You're ok with 100 Hz tuning steps. Yeah. Because you do not get the low-phase noise unless you can engage the PLL Locker. And the locker won't engage unless all the digits are shown on the 5 digit display. Oh, sure, you can lock and then de-tune the PLL circuit with a knob, which induces, you guessed it, more phase noise, as you're suddenly at the mercy of a variable resistor.
But ok, fast forward and look at this beast honestly.
Mechanics:
It has a ridiculous linked-(un)limited-slip differential scheme going on, using plastic gears, between the FM deviation and the frequency range knob. Yes, multiple layers of complex gears. It's like taking apart a mechanical alarm clock. The gears crack over time and then begin to slip or just fall into pieces.
Then there's the slider switches on the front panel. These break off because the enormous lever arm action coupled with the stiff click-click of the slider causes the brittle plastic to snap off. You can fix this by making your own metal replacements! Yea! And then you can glue them with epoxy to whatever is left inside the HP 8640B. Fun times!
Don't forget the camshaft that the range knob operates. Oh, yes, not only does the range knob operate a nasty arrangement of plastic gears in the front, but it also operates an enormous enigma of camshaft switches deeper inside which switch around how the UHF cavity oscillator is divided down.
But there's more to hate here. The PLL boards mate to the main board using these horrible and unreliable finger connectors. If yours hasn't failed yet, then it will!
And then there's the usual. RIFA capacitors at the rear, sealed pots that need to be cleaned inside somehow, the occasional failed capacitor. We all expect that stuff.
Oh and don't forget the broken gold fingers on the wafer-like switches. Yes, instead of normal wafer switches, HP etched switch paths on gold PWBs, sort of like how a modern handheld DMM handles the big switch. Except, to attach the wipers of the switch, they hot-melted the little gold fingers into (you guessed it) another plastic piece, which of course slowly falls apart. Don't forget to literally shake the gold pieces out when you first open one of these up -- they are basically impossible to replace without cannibalizing another instrument.
Ultimately, a small amount of relays or even solid-state switching, plus some standard switches, would have saved this instrument from such an early demise. Don't believe me? Instruments made before and after it used other not-completely-fantastic-plastic methods to control the circuits.
After many hours of gluing, grinding, probing, replacing, and swearing, you end up with a signal generator with low frequency resolution and phase noise specifications that it will never meet unless you have a cesium clock at 5 MHz to feed it with. To be fair I considered such (just for fun).
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HP 8640B
The controls are a interesting variety of technologies (analog meter, push button switches, crank, leds, sliders). It looks cool anyway.
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If we talk about scopes... I would add here HP54601A, it is claimed to be a 4 x 100MHz scope but it's sampling rate is only 20MS/s :palm: and it has about 4k of memory.
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service a miller 200 and then you will beg for the HP to come back when you have that stupid I beam design resting on fire bricks while you try to wash a heat sink
i got to the inner transformer and I think the hp power supply was still pleasant in comparison
it goes from surgeon to confined space zero gravity surgeon
thats a solid chassis design, part of the requirement for maintenance cleaning is machinists jacks or stacks of wood :-+
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I would also nominate the TDS3xx/4xx series. They were obviously a sort of learning phase in regard to user interfaces for Tek which was nevertheless foisted on the customers.
I rather like my TDS420A :-//
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Tek 465/465B/468
Absolutely horrible to dismantle if the H.T. and L.T. can smoothers on the main interface PCB dry out, (Even Tek themselves instruct you not to bother removing the main board and trying to repair the thing!) Sprague electrolytic capacitors either cost an arm, leg and a kidney, or they're pure unobtainium, altho' there are PCB adapters made to enable standard 10 mm pitch two–pin capacitors to go in the PCB, the supply of them is hit–and–miss, I guarantee every eBay seller won't have any when you get another one of these to do!
Tripler modules for the p.d.a. supply go s/c with monotonous regularity, involving much creativity in Araldite to repair and fill it afterwards, and everything, CRT included, has to come out to get at it!
'468 uses a gruesome ADC made by TRW Automotive that gets extremely hot and smelly in operation and failures aren't exactly unknown either!
Cam switches and attenuator modules notorious on these unless you're prepared to dismantle ALL the boards and cam–leaf operating assemblies and clean them METICULOUSLY as per the instructions in the manuals!
Fans are daft brushless d.c. things in the 465/465B that jam or get very badly worn bearings and if you skip repairing them, all the transistors in the front–end'll start showing their displeasure by popping off one after the other!
Innumerable tantalum failures as well!
Oh yes, the early series 465B manual from Artek I got didn't meet their advertised quality standards, it was full of engineers scribbles and blotches all over the circuit diagrams – get one from QService instead!
Chris Williams
PS!
(2024 Addendum !)
. . .Trigger slope switch knob/Trigger Slope Level Knob and Controls :–
. . .These are suddenly starting to get broken more often on sale units – both the knobs and the concentric control potentiometer/switch are EXTREMELY fragile!
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just a reminder if you are thinking about posting in this thread about a recent issue take a 2 week break :-DD
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I’ll second the Tek 2245/6/7 series. While they are decent scopes when functional, service is an absolute bitch, especially the main board on the bottom. Good luck extracting it to do any required work.
I would offer a counterpoint on this - the Tek 2245/6/7 are far easier to live with than the venerable 2465/7 due to not using the real PITA in Tek scopes - the infamous Dallas chip and leaking tantalum caps. My 2247A's are a joy to use They are keepers for general AF work and especially for monitoring RF modulation. That well-honed, excellent UI - including the adjustable orange graticule - is very tough to beat. Mine have been working for years without complaint.
Second that. The 2247A is to me the absolute best GP Tek scope out there for the money, and yes its an absolute pleasure to operate. Very intuitive and ergonomically friendly interface. Just change the internal Lithium battery once it starts complaining about every 8-10 years or so (simple procedure and done it already twice - and no danger of loosing any cal constants as they don't depend on the battery). And yes the PS can be at times a bitch but when mine quit I just replaced the whole board for a quick fix and back in business in less than 30 minutes. The 2247A is my go to scope 99% of the time (2465B on stby for that other 1%). Wish the 2465B would be as versatile as the 2247A with the higher bandwidth, but even with the CTT option installed recently it does not come close.
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IMHO, the worst tool from HP, by far, was the Logic Dart. Actually it was used as an example of how not to design a tool in some industrial design magazine i cant remember. I own one of these and can certify it is almost useless. It is appreciated as vintage collectable though.
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Looks like a glorified logic probe with some DMM and basic logic analyzer functions?
What makes it so bad?
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Looks like a glorified logic probe with some DMM and basic logic analyzer functions?
What makes it so bad?
I have one too and still consider it useful when no LA or MSO is available. Of course, with the demise of classical digital circuitry, those situations became rarer.
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Looks like a glorified logic probe with some DMM and basic logic analyzer functions?
What makes it so bad?
Holden : Describe in single words only the good things that come into your mind about... your LogicDart.
Leon : My LogicDart?
Holden : Yeah.
Leon : Let me tell you about my LogicDart.
[Leon shoots Holden with a gun he had pulled out under the table]
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Looks like a glorified logic probe with some DMM and basic logic analyzer functions?
What makes it so bad?
I have one too and still consider it useful when no LA or MSO is available. Of course, with the demise of classical digital circuitry, those situations became rarer.
Until the LCD failed on my LogicDart, it was probably my most used piece of test gear. I found it really useful when doing board bring-up or firmware dev, and was really handy to have for any low voltage work when visiting client sites. For I2C or SPI or other protocol decode it doesn't come close to a Saleae or MSO, but it helped me diagnose a huge number of HW & FW issues over the years.
I miss my LogicDart :(
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If we talk about scopes... I would add here HP54601A, it is claimed to be a 4 x 100MHz scope but it's sampling rate is only 20MS/s :palm: and it has about 4k of memory.
The sampling rate of the HP54600 series is rather poor (even with random repetitive sampling) and the 4kpts of memory are also relatively low (keeping in mind that contemporary digitising oscilloscopes like the Tek 2430 only had 1kpts), but despite all of that, they are a joy to use, relatively easy to work on and quite robust. Typical failure points are two vertical stage CRT caps and the Dallas NVRAM (both easy enough to replace/upgrade).
HP specifically designed the 54600 to introduce analog scope users to digitising ones at a reasonable price while offering a familiar interface.
Not trying to be an HP shill, but I think the 54600 series is far from being one of their worst products.
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Until the LCD failed on my LogicDart, it was probably my most used piece of test gear. I found it really useful when doing board bring-up or firmware dev, and was really handy to have for any low voltage work when visiting client sites. For I2C or SPI or other protocol decode it doesn't come close to a Saleae or MSO, but it helped me diagnose a huge number of HW & FW issues over the years.
I miss my LogicDart :(
The LCD is the same one as that used in an HP48. Prices on those have risen somewhat but they're still pretty common, and some even have the higher contrast black LCD. Maybe you could repair it with HP48 parts. Also, I thiink the HP48s tend to fail with zebra-strip connection problems so maybe the same techniques would repair your Dart.
I always wanted one, just because they seemed to address things that I worked on. But you're the first person I've seen finding them really useful so I haven't been willing to pay the going rate even on the rare occasions that I've seen one for sale.
It makes me wonder, though, if it's a concept that could be revisited. The Saleae analyser, as you say, is absolutely wonderful. That's a combination of a nice bit of mechanical engineering and some superb software. The later analog versions take that to another level. I don't know if it would be so good as a handheld or a phone accessory but .. maybe. The point is, it's relatively low tech (first version was very little more than an FX2 board) but has been designed and refined by someone who really knew what they wanted.
Maybe a thread somewhere else on designing a kick-ass logic probe ? A Flipper-zero for wired signals ?
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The LCD is the same one as that used in an HP48. Prices on those have risen somewhat but they're still pretty common, and some even have the higher contrast black LCD. Maybe you could repair it with HP48 parts. Also, I thiink the HP48s tend to fail with zebra-strip connection problems so maybe the same techniques would repair your Dart.
Interesting. I did try swapping in a display from a HP38G and it didn't work. I also have a HP48G which suffered PCB damage from a leaky battery, but the display should be fine. I don't recall if I tried that one... thanks for the tip.
I always wanted one, just because they seemed to address things that I worked on. But you're the first person I've seen finding them really useful so I haven't been willing to pay the going rate even on the rare occasions that I've seen one for sale.
I bought it on eBay nearly 20 years ago for AUD300, and got plenty of use out of it before the LCD went dark a few years ago. I tried to replace the polarizing film in the hope that might help, but I ended up cracking the screen.
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For Tektronix, their stuff seems electrically excellent. But mechanically, that is another story. Repair and maintenance of some of their earlier scopes (the 7000 series or the 22xx/24xx series) is a chore. Cam switches, endless brackets and screws, stuff packed into the chassis like sardines, etc. And I am not a big fan of the 500-series mainframe and plug-ins. Although I suppose it is nice to have a 6-bay mainframe packed with a variety of plug-ins, I find the individual plug-ins to be somewhat lacking in performance and I would rather use a dedicated piece.
The mechanics of the 7000 series was bizarre. Who thought beautifully and expensively machined actuators for bottom of the barrel 1 cent consumer slide switches made sense? The reliability was horrendous. Most repairs were things like replacing those slide switches which had been ripped apart by the nicely machined actuator.
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If we talk about scopes... I would add here HP54601A, it is claimed to be a 4 x 100MHz scope but it's sampling rate is only 20MS/s :palm: and it has about 4k of memory.
The sampling rate of the HP54600 series is rather poor (even with random repetitive sampling) and the 4kpts of memory are also relatively low (keeping in mind that contemporary digitising oscilloscopes like the Tek 2430 only had 1kpts), but despite all of that, they are a joy to use, relatively easy to work on and quite robust. Typical failure points are two vertical stage CRT caps and the Dallas NVRAM (both easy enough to replace/upgrade).
HP specifically designed the 54600 to introduce analog scope users to digitising ones at a reasonable price while offering a familiar interface.
Not trying to be an HP shill, but I think the 54600 series is far from being one of their worst products.
That demonstrates the arrogance of both HP & Tek, when they were pushing their early DSOs.
Although the interfaces were clunky in many such instruments, it was not an "unfamiliar interface", but the poor performance in real world scenarios that put people who normally used analog 'scopes to look at signals like analog video off DSOs.
The attitude was "You are just used to using obsolete methods---get with the future".
Being told that the horrific mess of aliasing on the screen was an equally viable way of displaying the information was insulting to people who used Oscilloscopes every day as part of their job, turning off many who had been enthusiastic about digital instruments.
It seems that was the beginning of the dominance of Sales over Engineering at both companies.
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I think its pretty insane to just re write the visual language of the electrical world.
IMO its kind of like pushing for a language change, grunts, faces and hand waving, when people are used to latin. The amsuing part is that like doctors of science were effected. I find it amusing if they switched a surgeons language set to grunts and hand motions. Is he talking about the spleen or a kidney?!
I tried to do a XY plot on a cheap DSO. I felt like I was working with some malfunctioned bullshit. The standard offering is basically something you see on star trek consoles after they get by disruptor fire. Spock might feel like dealing with that bull shit if the warp core is about to explode and it killed the previous operator. Did someone throw a pound of LSD into the ventilation system?
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Agilent U1602B, piece of junk:
Slow CPU
Terrible rubber silicone Keyboard, gotta press really hard to switch.
Worst case material in history, brittle polymer, would break at any load.
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Please remember that at the time it was introduced, the 500 stuff was leading edge.
Yes, it should have been put out to pasture before the first moon landing, but in the 50s and early 60s it was something else.
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If we talk about scopes... I would add here HP54601A, it is claimed to be a 4 x 100MHz scope but it's sampling rate is only 20MS/s :palm: and it has about 4k of memory.
The sampling rate of the HP54600 series is rather poor (even with random repetitive sampling) and the 4kpts of memory are also relatively low (keeping in mind that contemporary digitising oscilloscopes like the Tek 2430 only had 1kpts), but despite all of that, they are a joy to use, relatively easy to work on and quite robust. Typical failure points are two vertical stage CRT caps and the Dallas NVRAM (both easy enough to replace/upgrade).
HP specifically designed the 54600 to introduce analog scope users to digitising ones at a reasonable price while offering a familiar interface.
Not trying to be an HP shill, but I think the 54600 series is far from being one of their worst products.
That demonstrates the arrogance of both HP & Tek, when they were pushing their early DSOs.
Although the interfaces were clunky in many such instruments, it was not an "unfamiliar interface", but the poor performance in real world scenarios that put people who normally used analog 'scopes to look at signals like analog video off DSOs.
The attitude was "You are just used to using obsolete methods---get with the future".
Being told that the horrific mess of aliasing on the screen was an equally viable way of displaying the information was insulting to people who used Oscilloscopes every day as part of their job, turning off many who had been enthusiastic about digital instruments.
It seems that was the beginning of the dominance of Sales over Engineering at both companies.
HPs first digital oscilloscopes were a mix of things that looked and felt like traditional analogue oscilloscopes and things that looked and felt like a logic analyser. I loved the logic analyser style ones, but they sunk without trace so badly in the market its hard to even find references to them on the internet. So, they played up the products real engineers put real money into.
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RE the 8640B slide switches --- fighting that battle right now - a photo of a replacement metal part will save me some thinking about what might work ---aluminum, brass? bent up out of shim stock?
it looks like these are made out of two pieces somehow molded together based on the different colors of plastic. The key to "experimenting" is that it is so hard to get at these that it's pretty much impractical to try something and fail.
now updating it with some pictures of a kludy but hopefully effective repair - one was missing the handle, one had a broken handle.
.010 brass shim stock and a slice cut from the "handle" part of an old key and we have (see photos)
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RE the 8640B slide switches --- fighting that battle right now - a photo of a replacement metal part will save me some thinking about what might work ---aluminum, brass? bent up out of shim stock?
it looks like these are made out of two pieces somehow molded together based on the different colors of plastic. The key to "experimenting" is that it is so hard to get at these that it's pretty much impractical to try something and fail.
Try to replace it with a PCB - DIY from clad, or draw it up and order online. You can solder(carefully!!!) the contacts in place, or, if you find proper rivets, rivet them in place.
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thanks - I updated my post just above to include the attempt to repair with shim stock - I'm waiting for the epoxy to finish drying before I reinstall and see what happens. it looks like it ought to be OK, and if so, the metal should last a lot longer than that plastic did... not only is it old plastic, but in a prior life it must have been near a window and the sunlight doesn't help either.
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second hint for this signal generator ... there are white plastic gears that make up a differential, and the gears split - I just removed the gear and set the brass insert on my soldering iron and let it heat up, the gear wants to close back to how it was molded and that's what it did, it's all good now. try it.