[HN Gopher] Agilent 2000a / 3000a Oscilloscope NAND Recovery
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       Agilent 2000a / 3000a Oscilloscope NAND Recovery
        
       Author : sharpshadow
       Score  : 143 points
       Date   : 2024-06-19 13:20 UTC (9 hours ago)
        
 (HTM) web link (salvagedcircuitry.com)
 (TXT) w3m dump (salvagedcircuitry.com)
        
       | pandemic_region wrote:
       | This guy knows his oscilloscopes.
        
       | aardvarkr wrote:
       | I love seeing ridiculously technical investigations like this. It
       | has zero relevance to me but it's just sooo satisfying to see
       | someone solve a tough problem.
        
       | a1o wrote:
       | > the MSO adapter can accept low power signals up to 40v, but it
       | offers no input protection when the host oscilloscope is off.
       | Thus, if the DUT (Device Under Test) has a short of some kind
       | near the area of probing, and the host oscilloscope is not
       | powered, there's a good chance you've just damaged the Maxim
       | MAX9201 comparators in the logic analyzer section of your scope!
       | It's worth checking all 10 pins for voltages outside the MSO
       | operational range.
       | 
       | Whoa, it's been a long time since I haven't used these tools but
       | I learned now I was very lucky when using because I didn't knew
       | this and didn't check the voltages when using the logic analyzer
       | in the scope I had at the time from Tektronix - which I guess had
       | the same type of limitations.
        
       | janice1999 wrote:
       | If you like this kind of content, I highly recommend checking out
       | the Youtube channel 'The Signal Path' [1]. It has some fantastic
       | technical teardowns and repairs of instruments, including really
       | high frequency equipment.
       | 
       | [1] https://www.youtube.com/channel/UCKxRARSpahF1Mt-2vbPug-g
        
         | hobs wrote:
         | You probably already watch him, but Marco is also great when it
         | comes to similar content (he loves his multimeters)
         | https://www.youtube.com/@reps
        
           | doormatt wrote:
           | Gloves and PPMs!
        
         | n_plus_1_acc wrote:
         | I like bigclive. He takes apart cheap electronics from eBay.
        
         | nativeit wrote:
         | Curious Marc[1] works on a lot of old HP test equipment, and
         | he's also a Silicon Valley native, frequent contributor to the
         | Computer History Museum, and his channel features an HN
         | regular, Ken Shirriff, who can reverse engineer everything from
         | vintage Russian Soyuz components to uncapped IC packages.
         | 
         | 1. https://youtube.com/@curiousmarc?si=pHOewmmWbDDmSSZb
        
       | bloomingeek wrote:
       | It's so good and satisfying to see a person ply a trade to
       | success. When I find myself stressed out for some reason, I like
       | to do something I'm well trained at to help my brain kind of
       | reset, which often gives me a different way of looking at what
       | stressed me in the first place.
        
       | hristov wrote:
       | This is very interesting. I just have one minor nitpick. Broadcom
       | did not buy Avago, Avago bought Broadcom. They then changed their
       | name to broadcom as it was more recognizable in the industry
       | (while keeping their old stock ticker AVGO as that was more
       | recognizable in the financial industry).
       | 
       | This is entirely a tangent but the rise of Avago from a minor
       | second rate spin off from a spinoff from HP to one of the biggest
       | and most profitable companies of the world (and one that is many
       | times the size of current HP), is one of the most unusual mostly
       | untold stories of the modern business world. It is a story of
       | success (by Avago and Broadcom engineers and management) and
       | incredible incompetence (by hp management that let them go for a
       | pittance).
        
         | jjoonathan wrote:
         | Oh wow, I was just transplanting some TC702 amplifiers to save
         | the doubler in an old 50GHz HP signal generator... would that
         | have been designed by these guys back when they were part of
         | HP?
         | 
         | https://www.keysight.com/us/en/assets/7018-04165/application...
         | 
         | EDIT: that's registration-walled, but this HP Journal article
         | isn't. https://archive.org/details/Hewlett-
         | Packard_Journal_Vol._42_... The amplifiers in question are
         | blue-colored in the background, and the doubler that uses them
         | is the spiritual successor to the rear-most golden module.
         | 
         | EDIT2: yep, the timeline lines up. The HP journals with these
         | amplifiers were early 90s, and "This division became part of
         | Agilent Technologies when HP spun off its test and measurement
         | business in 1999. Later, in 2005, Agilent spun off its
         | semiconductor products group, which became Avago Technologies.
         | "
        
       | cardiffspaceman wrote:
       | // "You will need an oscilloscope, passive probes, ..."
       | 
       | That's my stop.
       | 
       | This engineer is determined! Built a test circuit to identify one
       | part.
        
       | prbs23 wrote:
       | This is an awesome write up!
       | 
       | I have one of these scopes, with exactly this issue after a long
       | period in storage. When I was looking into it a few years ago the
       | failure mode was known but I couldn't find a recovery procedure.
       | I'll need to give this a try when I get a few hours. I have been
       | putting off getting a new scope in hopes that I could repair this
       | issue.
        
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       (page generated 2024-06-19 23:00 UTC)