And here is the second part of the $1 multimeter deal from the last Hamfest. Together with Micronta 22-201U analog meter reviewed here I picked up this 3.5 digit digital one of a similar age. The poor thing looks like it had a rather difficult life!
Updated 11/2016
I’ve been lucky enough recently to score a Keithley 2304 power supply off ebay for a measly $75. For those unfamiliar, these are high speed battery simulator units capable of measuring very low currents and also behaving like a battery and sinking current.
Original ebay picture
Today we have two tiny multimeters to take apart and see what we can learn from how their designs progressed:
On the left is Hioki 3217 and on the right – Beckman DM78
The latest addition to our vintage collection is a Keithley 130A handheld DMM from the mid-eighties.Keithley is not well known for its handheld DMMs, or at least I’ve never heard of them. It’s a 3.5 digit 0.25% instrument made in mid 1980s
The thing is tiny! Shown next to the EEVblog uRuler
I’ve been looking for a good clamp meter for a while now. While there is plenty of no-name cheap meters on Ebay, I figured I’d wait till something better “washes ashore”. So when a Yokogawa meter got caught in my ebay filters one day, I grabbed it. Yokogawa is a Japanese company, well known for their power measurement equipment. This meter has a nice mix of AC and DC current ranges fitting my low to medium current measurements needs. It is also a recent model, still being made and supported- a rarity in my lab setup of 20+ year old equipment Continue reading
Another ebay find- a vintage Keithley 172 multimeter. The datecodes on the parts range from 1978 to 1984, placing the final assembly somewhere in mid-1980s. It seems fully functional, but could use a bit of a calibration to regain its past precision.
An ebay find made its way into the lab- an industrial quality DMM from Hioki, made in 1984! The meter has some pretty good specs as shown in this datasheet:
Today we are unpacking a brand new LCR meter from a company called Tonghui in China. It was purchased on ebay and took less than a week to arrive.
Chinese market packaging
Today’s quick visual teardown is of an 1984 vintage Keithley 197 microvolt DMM, Despite considerable age, it’s still quite alive and kicking and very useful for measuring low currents and voltages.
Today’s quick teardown target is a 1985 vintage electronic load made by Kikusui of Japan. It came from eBay with a noisy fan, but was otherwise fairly functional despite the considerable age.
Only 2 inches wide