Refurbishing a General Radio Company 1531AB Strobotac unit built in 1975.Continue reading “General Radio Co. 1531AB Strobotac Refurbishment”
Adapting the IV-18 IceTube clock design to use the 13 digit IV-27M VFD tube.Continue reading “IV-27M IceTube Clock Project”
Cleanup, restoration, and calibration of a Hewlett Packard (HP) 6 1/2 digit 3456A Digital Voltmeter.Continue reading “Hewlett Packard 3456A Digital Voltmeter”
After finishing the IceTube clock version 1.31 build for myself, I was ready to work on the board design for some IceTube clocks as gifts. I could have used the existing V 1.31 boards, but I wanted to use an up to date design that incorporated all the hardware improvements over the past 10 years while still staying with a thru-hole design.Continue reading “Updated IceTube Clock Design”
Revisiting IceTube clock designs and construction, after performing some small repairs on an IceTube clock I built back in 2010.Continue reading “IceTube Clocks”
Updating a Hafler DH-110 preamplifier from the early-80’s with new electrolytic capacitors, along with a cleanup and then testing.Continue reading “Hafler DH-110 Preamplifier Refresh”
This is a continuation of my Wien Bridge Oscillator module design project. It houses all the parts needed for a portable Ultra-Low THD dual-frequency sine wave generator.Continue reading “Ultra-Low-THD Sine Wave Generator”
Trouble shooting and performing modifications on a HP 3437A System Voltmeter from 1984.Continue reading “Hewlett Packard 3437A System Voltmeter”
I found myself in need of a very low-distortion 1,000 Hz sine wave
generator for an upcoming project.
A quick search on Ebay found several used pieces of test equipment that met or exceeded my requirements, but were priced at well over $1,000 USD.
I did also find some low-cost China sourced 1 kHz generator boards, but they had a distortion of 0.1% which was way above my 0.005% limit.
My current test gear includes a Keithley 2015 THD Multimeter with a low distortion sine wave generator, but it is only capable of 0.03% THD at 1 kHz.
It was time to see if I could build something for under $100 that would meet my needs.
Another local Ebay find was this Hewlett Packard HP 403B AC Voltmeter in a protective HP vertical case. The case did an excellent job of protecting the meter over it’s now 48 year life.Continue reading “Hewlett Packard HP 403B AC Voltmeter Restoration”
I found myself in need of a rechargeable battery tester, so I went off to search the internet for a DIY tester.
I was pleasantly surprised to find that John Lowen, had built a Rechargeable Battery Capacity Tester (v2.0), and also developed the PC interface software for desktop use.
Even better I found that Paul V. had also built the same tester and had made several improvement in the design and software.
Everyone should have at least two of these ESI 250DE Impedance bridges.
Well that was not my first thought when purchasing this unit on Ebay.
I was still having some issues with the “Internal DC” detector circuit on my existing unit, and the price of this unit was extremely reasonable. After dozens of hours troubleshooting the first unit with no solution, my thought was to compare the two circuits and salvage parts from the new unit if necessary.
An updated version of the Millivolt Meter project from May 2016, with dual range selection, calibration selection, improved software, and updated board layout.Continue reading “Millivolt Meter Version 2”
Finally assembling the electronic load modules for some basic testing of minimum voltage at different current levels, and heatsink thermal capacity.Continue reading “Linear MOSFET Electronic DC Load — Part 2″
Repair and cleanup of a vintage Keithley Instruments 600A Electrometer.Continue reading “Keithley 600A Electrometer Repair”
Cleanup and repair of an ESI Dekastat model DS1463 12K Ohm coaxial decade resistor.Continue reading “ESI Dekastat DS1463 12K decade resistor repair”