Vintage Hewlett Packard P*rn- HP 5510A Automatic Compensator Teardown - Page 1
Forum section: electronics / testgear

author: Inconel-oh-el
author_rank: Contributor
timestamp: November 12, 2019, 11:38:09 pm
content: Hi-I was going through my University's surplus store and came across this old bit of HP kit. I'm a bit of an HP fanboy, so it piqued my interest, however a quick google showed it was part of a hopelessly obsolete optical measuring system. I must (shamefully) admit, I bought it to use as an enclosure for a projectAfter I opened it up, I knew I would feel way to guilty gutting the poor instrument- too much gorgeous engineering from HP to destroy without sharing.Dave- are you interested in this for a vintage 2 minute teardown? If no, I'll sleep a little easier after "repurposing" it having at least posted a few shots.

author: Inconel-oh-el
author_rank: Contributor
timestamp: November 12, 2019, 11:42:37 pm
content: More Shots- Yes, the colors match the resistor color codes!Shiinyy. Not sure which part of this is the voltage reference, just posting the images now before I dig in a little more

author: Inconel-oh-el
author_rank: Contributor
timestamp: November 12, 2019, 11:50:19 pm
content: Digital rubbish, all discrete logic, of course with custom HP part codes. Looking around for date codes puts it around 1983- is anyone familiar with this, or the 5505A system it was part of?Edit: If people are interested, I can post more/better photos later. Unfortunately though I have a controls theory exam to study for as well

author: 0culus
author_rank: Super Contributor
timestamp: November 13, 2019, 04:38:16 am
content: Mmmm, those are some tasty gold traces too.Please do share more pics, and come over to the Test Equipment Anonymous thread and show us the REST of your stuff.I, too, have a significant collection of -hp- gear; virtually all of my RF stuff is -hp-. I only have one -hp- o-scope though, a 1727A.

author: mjs
author_rank: Regular Contributor
timestamp: November 13, 2019, 06:14:45 am
content: This is part of intereferometer system for measurements / lithography steppers etc.https://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1970-08.pdfThe two-frequency laser in the system has very stable *frequency*, so to user the laser for distance measurement outside a vacuum, you need to compensate for speed of light in medium. In air, the speed changes roughly 1ppm/K and also due to pressure (about 1 ppm/333 Pa) and humidity (ppm/30%). This unit, when fed with sensor data, compensates for those.I've got 5517C based interferometer system with my own MCU-based readout, but no pressure/temperature/humidity compensation yet - maybe I should add some Sensirion temperature/humidity sensor and BMP280 for ambient pressure..

author: Inconel-oh-el
author_rank: Contributor
timestamp: November 13, 2019, 08:59:43 pm
content: Mjs, that HP journal was a very interesting read. I've worked in several machine shops and with plenty of metrology type instruments (CMM/SLM inspection, etc), had no idea that it was part of one of those systems. I believe I misspoke calling them obsolete! My quick Google searches before impulsively buying it didn't show the laser heads for this system, which seem to still hold plenty of value.Currently trying to convince myself that I don't need a laser interferometer. I don't need a laser interferometer....

author: Inconel-oh-el
author_rank: Contributor
timestamp: November 13, 2019, 09:10:29 pm
content: Quote from: 0culus on November 13, 2019, 04:38:16 amHa. That thread is about as therapeutic as a 40 ounce is to an alcoholic. I'll see if I can tidy up and post a few pics of my gear. I like HP because their service manuals are incredible, and nearly any older instrument can be brought back broken- meaning I can buy them dirt cheap on eBay and get them runningI think my Dad has an old 1740a in storage that we really should try to fix.