Radiometer RV24 vacuum tube DC AC voltmeter ohm 1964

Interesting tube design in this radiometer from about 1964, weight 6.7MHz Frequency range 10Hz to 50MHz using direct AC input. Length 26cm, Width 20cm, Depth 32cm, power consumption under 20Watt. Tubes : 2 x ECC81 dual triode, 2 x EAA91 dual diode,
Differential amplifier, regulated filament, non regulated anode voltage,
forward diode voltage compensation, i was able to fix minor mecanical details and calibrate it, removed 1.5V D cell for resistance measurement.
this is my number 27 radiometer video.
Full manual and schematics at PEEL.DK for most Danish vintage instruments.
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#teardown
#radiometer
#vintage
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I use auto generated subs, i am sorry there are a few spelling errors,
maybe one day they can do it better..
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(Thanks to all my Sponsors / Traders / Swappers / Sellers / Buyers, without your support and constant flow of cool items in/out, none of this would be possible)

[@tardusmerula6102]

Hi! I have been using several electrochemical instruments by Radiometer , like pH and oximeters, in the 80's. State of the art, at last in Europe, at the time. Most data still holding. Your rewiev remind me of the smell of the instruments, always on, mixed with various reagents and chemicals. What a happy times were those.

[@VoidElectronics]

No way! For a second I thought KZbin recommended me my own video because I have 2 of those voltmeters and I also made videos about them. Have a look at my video. :D At 14:40 I would advice checking the batteries under load or checking their internal resistance. I had some very old Hellesens battery in mine and the voltage was ok on the multimeter but it dropped to almost zero with a 10k in parallel. At 16:21 I wouldn't call the calibration so easy because all the trimpots are on the bottom, but the meter really has to stand upright for a correct reading. Also, I'm pretty sure that due to thermal and noise reasons it would be a good idea to calibrate it with all the panels in place, which makes getting to the trimpots a complete nightmare. At 22:30 I had no idea what the diode stack does. Nice circuit analysis!

[@TeardownOZ2CPU]

THANKS, you are absolutly right, a battery must always to tested at load, to tell if it contain anything good, but in my case the ohmmeter in this unit uses micro amps, and i only needed it to work while making the video, now the battery it takes out, since i recommend to store instruments WITHOUT batteries of any type

[@VoidElectronics]

@TeardownOZ2CPU Yeah, for storage I would take the battery out too. The instrument is too nice to be destroyed by a shitty battery.

[@TeardownOZ2CPU]

@VoidElectronics i have devoted a large portion of my time on this planet, to tell people : please remove batteries from ANYTHING you dont use all the time. looks like i have failed my mission.. so please help me folks..

[@zebo-the-fat]

Very accurate considering it's age!

[@douro20]

Nowadays Radiometer is entirely invested in manufacturing of medical diagnostic equipment. They made the first commercially available blood gas analyser back in the 1950s.

[@cajuncoinhunter]

I would think that if that unit was on a shelf higher than 12 inches then there would be a difference in height .... When the operator would press the selector button his finger would be putting a little bit of upward pressure on the selector ..... After a few years of use it would be showing the use ... Just a thought ...

[@leopiipponen7693]

Even modern measuring devices should be allowed to warm up properly in order to be as accurate as possible :)

[@TeardownOZ2CPU]

most modern equipment is full of temperature sensors and thermal compensations of all sorts of analog things that is affected by temperature, this means you get full resolution and full accuracy from just powered up to many hrs later.