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 ...
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 ...
I have now been able to run the power meter at full resolution (even if it's ...
I recently purchased a broken EIP 545B microwave frequency counter on ebay. It was very inexpensive (around 150€ delivered), but obviously, non working.
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 ...
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 ...
This is the part 2 of the series about my HP 3562A Digital Signal Analyzer, quickly describing the Digital Section of the instrument.
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 ...
This is the part 3 of the series about my HP 3562A Digital Signal Analyzer, quickly describing the Analog Section of the instrument.
The analog section consist in 6 boards:
- A30: Analog Source
- A31: Trigger
- A32, A34: Input ADCs
- A33, A35: Input
This board is mainly ...
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.
The display unit is a HP1345A Digital Display without the option 714 (wich adds a ...
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 ...
In order to build a replacement display for the HP34970A data acquisition unit, I needed to understand the communication protocol between the CPU board and the front panel assembly.
The unit is built with four boards:
- A1 is the main bard, with the PSU, the main controller and ...
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