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+=================================
+ HP3562A Dynamic Signal Analyzer
+=================================
+
+:Author: David Douard
+:Category: Electronics
+:Tags: HP3562A, repair, test equipment, DSA
+:series: HP 3562A
+:series_index: 1
+
+One of my old test gears waiting for my attention in the cellar was a
+HP 3562A Dynamic Signal Analyzer. Back then I bought this device
+mainly for doing audio analysis (I was building my HiFi system, mostly
+based on Nelson Pass' schematics), mainly to display spectrum
+responses and compute THD and so.
+
+I did not reall know what this test equipment is capable of. But `Dave
+Jones's video #528`_ (and several wonderful videos on `w2aew's
+channel`_) gave me the desire of playing a bit more with this old but
+very impressive HP3562A.
+
+.. _`Dave Jones's video #528`: https://www.youtube.com/watch?v=Y0jkPLuFdnM&t=1876s
+.. _`w2aew's channel`: https://www.youtube.com/user/w2aew
+
+
+Quick tour
+==========
+
+Here is the beast:
+
+.. image:: {filename}images/hp3562a/front.jpg
+
+I said the beast, because despite being an amazing piece of test
+equipment, it's also very big (576mm x 426mm x 222mm), very heavy
+(26kg) and... unfortunately quite loud.
+
+My version of the instrument is rather "recent", and manuals available
+on Keysight web site concern only the earliest models
+(ref. 03563-90210) and are of poor quality, with missing pages etc. So
+I bought the correct Service Manual (HP ref. 03562-90213) on ebay from
+`Artek Media`_.
+
+.. _`Artek Media`: http://www.artekmedia.com/
+
+Since it was on my "bench", I decided to see a bit inside, using the
+occasion to investigate and fix the only real problem I have (as far
+as I know) with my device: the dimm display.
+
+.. image:: {filename}images/hp3562a/front_open.jpg
+
+The unit consist in mostly 4 parts:
+
+- a big switching power supply (with huge capacitors) on the left side
+ of the enclosure, under the display,
+
+- the display unit: a very nice HP1435A Digital Display; we'll discuss
+ it a bit more later,
+
+- the digital section consisting in 8 boards (rear right),
+
+- the analog section consisting in 6 boards (front right).
+
+
+The general block diagram:
+
+.. image:: {filename}images/hp3562a/hp3562a_block_diagram_new.png
+ :alt: General block diagram of the HP3562A
+
+The instrument is built around 2 buses:
+
+- the control bus which allows the main CPU to control all the
+ assemblies, and
+
+- the global bus which is used to transfer measurement data between
+ assemblies.
+
+In the HP3562A, the process control is distributed away from the
+system CPU: each assembly has its own processor or state machine which
+controls its local operations. The main CPU tells each assembly which
+process to execute and monitors the overall functionning and data
+processing of the instrument.
+
+For the record, the block diagram from Service Manual 03562-90219
+looks like:
+
+.. image:: {filename}images/hp3562a/block_diagram.png
+ :alt: General block diagram of the HP3562A from earliest Service Manual
+
+
+Power Supply
+============
+
+.. image:: {filename}images/hp3562a/hp3562a_a18_psu_block_diagram.png
+ :alt: Block diagram of the switching power supply unit
+
+
+.. image:: {filename}images/hp3562a/a18_psu.jpg
+
+The primary capacitors are huge Sprague caps (1400µF 250V):
+
+.. image:: {filename}images/hp3562a/caps.jpg
+
+The power line filter is also pretty impressive:
+
+.. image:: {filename}images/hp3562a/filter.jpg
+
+The PSU generates:
+
+- 5V @30A (!)
+
+- +/- 30V
+
+- +/- 15V
+
+- +8V
+
+- +2.6V
+
+The switching chopper runs at 128kHz and is regulted on the 5V output
+rail by PWM of the primary transformer. All secondary voltages but the
+5V are generated by linear regulators.
+
+
+Next
+====
+
+In the `next part <{filename}hp3562a_2.rst>`_, we will describe the
+Digital Section of the instrument.