jeu. 15 février 2018

EIP 545B RF Frequency Counter - Part 4

This part is about my attempt to modify the firmware to "fix" the problem of weird intial setup: a -160MHz offset and a resolution set to 5 digits.

In the previous part, we figured some probable spots in the firware where these default setup configurations might be set.

EPROM checksums ...

ven. 26 janvier 2018

EIP 545B RF Frequency Counter - Part 3

Default settings

One of the annoying thing with this 'SPECIAL' edition of the firmware are the default settings:

  • Frequency Offset -160MHz
  • Resolution 5 digits

One of my goals while disassembling the formware was to 'fix' these defaults settings. I was wondering wether they where located in an undocumented part of ...

sam. 20 janvier 2018

EIP 545B RF Frequency Counter - Part 2

I've started a discussion on the eevblog forum to gather a bit help for my project. And I did well since a few fellows did help me a lot on some aspects.

I have now been able to run the power meter at full resolution (even if it's ...

mer. 20 décembre 2017

EIP 545B RF Frequency Counter

I recently purchased a broken EIP 545B microwave frequency counter on ebay. It was very inexpensive (around 150€ delivered), but obviously, non working.

The EIP 545B RF Counter

The device was described as "does not power up", an is clearly not in very good condition. Quite dirty, battered, with the band 2 BNC connector ruined ...

ven. 22 septembre 2017

HP ZR24W PSU Repair

A friend of mine had a problem with his (a bit old) 24" HP monitor: the device was working properly, but only for a while (few minutes at most).

Looked like a good candidate for a quick repair, problem being most probably bad caps are so.

The first step was ...

mar. 03 janvier 2017

HP3562A Dynamic Signal Analyzer

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 ...

mar. 03 janvier 2017

HP3562A Dynamic Signal Analyzer - Part 2

This is the part 2 of the series about my HP 3562A Digital Signal Analyzer, quickly describing the Digital Section of the instrument.

Digital Section

The unit is quite capable, since the main CPU is a 68000 (not exactly of small CPU for the time).

The 8 boards are:

  • A1 ...

mar. 03 janvier 2017

HP3562A Dynamic Signal Analyzer - Part 3

This is the part 3 of the series about my HP 3562A Digital Signal Analyzer, quickly describing the Analog Section of the instrument.

Analog Section

The analog section consist in 6 boards:

  • A30: Analog Source
  • A31: Trigger
  • A32, A34: Input ADCs
  • A33, A35: Input

Analog Source

This board is mainly ...

mar. 03 janvier 2017

HP3562A Dynamic Signal Analyzer - Part 4

This is the part 4 of the series about my HP 3562A Digital Signal Analyzer, quickly describing the HP 1345A Digital Display unit as well as the repair I had to do on it.

Display

The display unit is a HP1345A Digital Display without the option 714 (wich adds a ...

mar. 22 novembre 2016

HP 3456A Digital Voltmeter

A very long time ago, I bought a venerable HP 3456A Digital Voltmeter. Back then, I had no clear idea what kind of device it is; but it was cheap. It worked quite fine (it is indeed not calibrated), but I noticed for a while that it was quite unstable ...

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