EEVblog #1237 - Old School Teardown: HP3785A Jitter Analyser

Old school, they don't make'em like this any more.
Teardown of the HP 3785A Jitter Generator & Receiver with beautiful HP bubble LED displays.

#Teardown #Vintage #HP

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[TheAwfulInternet]

Love old HP science equip. Works of art and engineering.

[X-OR_]

The Board Tabs are arranged in the Classic Resistor Code Colors:

Black Brown Red Orange . Yellow . Green . Blue . Violet . Gray White.

[DanafoxyVixen]

Dont forget to remove that memory backup battery.. its starting to corrode the traces

[mlkbob]

This is likely to have been made in South Queensferry outside Edinburgh in Scotland. My Dad was a test engineer that worked on these and I was taken in when he was doing overtime on occasion to see him at work.
These were made to order and went through a extensive testing and calibration process including being placed in a oven for a day to operate at it is maximum operating temperature before being sent out. This seemed particularly good at highlighting parts that didn't meet specs and it these would be hand replaced. So the rework shown might of been done at the factory as part of the testing and calibration process.

[sbalogh]

0:06 Your dumpster is a veritable treasure trove.
5:10 Those boards are a work of art, so beautiful.
I really love the old HP equipment. They were all so beautifully engineered.

[PauloSantos-cvbi]

Those TI chips with the Portugal mark were made at TISEP (Texas Instruments Samsung electronica Portugal) which closed in 1998. The company was housed in a six building complex, covering over 15, 000 square meters, and were located In Porto, around 20min from my home. It was the only semiconductor company in the country and the only assembly and test site for ICs in Europe for both TI and Samsung.

[stiff]

6:29 The edge connectors at the top of the riser board is a board to make the other cards stick out of the top not for a test/diagnostic card.

[noakeswalker]

Great to see this teardown. Bubble led displays as late as 1984 ?? :o) Almost certainly this was made at HP's Queensferry Telecom Division, which was near Edinburgh, Scotland. That site began in about 1966, and made telecom stuff, scopes, much of that lovely test gear, and medical equipment too. Became an Agilent site after the HP/Agilent split (1999). Site closed in 2010. Dave (ex HP UK )
(BTW Dave: HP in the UK was also at Bristol since 1984 - we made dig data tape drives right through 90s and 2000s. Also there was an HP Labs research building of some note on the site. Tape drives are still made there, but not for much longer, and Labs have vacated the site 2 years ago - that's the end of an HP era)

[stevenleibson]

That jitter tester was very likely made in HP's South Queensferry (Scotland) division, which focused on telecom test gear in the 1970s. My new bride and I (both HP Engineers) visited there on our honeymoon in 1979. They were very hospitable, despite our just dropping in. Those were the days.

[pocoapoco]

Also notice the color coding bands on the coax indicating the color of the local board and the remote board.

[pedromms]

16:37 Hello from Portugal!!!
I'm really sorry that we don't have here any IC's manufacturers anymore :(

[jcctube]

I don't want to brag, but I recently designed a board with spare fuse holders plus a LED so the spare fuse holders are also fuse testers :-)

[dentakuweb]

I saw some 54 series in there too.

Chris Svec talks about "empathy driven development" in software.
This is like empathy driven hardware development where it was built in a way that makes it much nicer to service.

[joehubler]

I thought I was the only guy with that beast on my bench! got it on eBay for $10. the seller stated, " I don't know what it is, I don't know what it does, I don't know to test, so sold as is." it works great!

[josuelservin]

Those spare fuses certainly won mi heart, absolutely beautiful!

I used one of these in the old GEC Telecommunication Labs. My job was to design a much cheaper alternative for field technicians, albeit with less functionality. Rms jitter measurement was done by illuminating a small light bulb and photo detector!!

[Spookieham]

Built by engineers for engineers. Built to a specification, the price wasn't important.

[MrDannyisr]

I used the 3780a back in the day, late 80s early 90s, Measuring BER for the Air Force communications systems. Very useful to find bad card that was introducing noise.

[ThSu]

Noticed how the color coding of the board latches are the same as used for resistor color coding.

[flomojou]

Bubble displays are awesome, such a unique look! When I was a kid in the 70s I had a digital watch with a bubble display, where you had to press a button to illuminate the display, so cool until I lost it :(