Episode 1285 A nice old AC voltmeter good to 4MHz. Condition unknown. Came from a Ottawa University past video on HP 427 Multimeter: • #460 HP427A Vintage Mu... Be a Patron: / imsaiguy
I graduated about 25 years ago from Carleton U in Ottawa, but I never saw this beast there! Back then we had HP 5 1/2 digit DVMs in our EE analog labs. Probably it belonged to other departments and they didn't know what to do with it. Someone must have punched it instead of turning the knobs or push it off the roof instead of unplugging it.
it's pretty weird to see a voltmeter you sold on ebay show up in one of your favourite youtuber's videos. I got this meter from a friend who had a stock pile of about 30 of them in his garage. all from a disposal at carleton. sorry about the crummy state that it is in, I did a quick check to see if it powers on and gives out any reading. that being said I vaguely remember it saying that it has a 600 ohm input so that might be the issue with the readings. I'm super happy to see that you are doing a teardown and cal of these meters. :)
also those bodges must've been from someone at carleton since neither the person I got the meter from nor myself have really looked inside them too much.
These still appear in the HP catalog in 1986, but are not present in the 1988 catalog. I have several of the 400 series meters, and a 3400. Reliable and useful, plus they look cool on the bench.
Another great find. The only tricky bit will be the meter calibration screw. The only thing I found on ebay was the service manual for one at £13.27 plus £12.33 shipping. LOL
I picked up a 400E at a Ham Flea Market last year. Got it because it is HP and has NASA/JPL asset tags on it. I figure given the vintage status it could have been used for Apollo work. I started to replace the HP power cord jack with a standard IEC jack. Drilled out the connector - wires dangling still. Need to finish it. Too many projects at once...
I saw "7152" on one of the sprague caps towards the back, so possibly a 1972 build date? That would mean HP sold these things for at least six or seven years
I used one of those meters to do signal-to-noise measurements for communications equipment. I don't recall the one I used had a switchable filter, though.
Hi, that's funny, I was looking at this exact meter on Ebay, but ended up buying the 3400 model 😂 Edit: A mechanical 0 setting will have a broken pin on the gear disc, the poor guy had to suffer when he got his hand bent like that Nice day 🙂 Tom
Hello I have the FL version of this meter. There is nothing wrong with needle the meters are sealed. Mine sets below the zero just like yours. 73 Lawrence KF4HNF.
This is true for the FL version. It has a logarithmic meter movement (dB scale is linear, but voltage scale is log.) in that case, zero volts is actually negative infinity dB, so there is no zero adjustment screw, and the meter reads off scale to the left with no input. The 400F (without the L) has a zero adjustment screw, and the meter should read zero when the unit is turned off. It may read slightly above zero when on, of course, due to the high input impedance.
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I graduated about 25 years ago from Carleton U in Ottawa, but I never saw this beast there! Back then we had HP 5 1/2 digit DVMs in our EE analog labs. Probably it belonged to other departments and they didn't know what to do with it. Someone must have punched it instead of turning the knobs or push it off the roof instead of unplugging it.
it's pretty weird to see a voltmeter you sold on ebay show up in one of your favourite youtuber's videos. I got this meter from a friend who had a stock pile of about 30 of them in his garage. all from a disposal at carleton. sorry about the crummy state that it is in, I did a quick check to see if it powers on and gives out any reading. that being said I vaguely remember it saying that it has a 600 ohm input so that might be the issue with the readings. I'm super happy to see that you are doing a teardown and cal of these meters. :)
also those bodges must've been from someone at carleton since neither the person I got the meter from nor myself have really looked inside them too much.
Cool
the input impedance is 10M ohms. if you use the dB scales then it is up to you to add a 600ohm load.
These still appear in the HP catalog in 1986, but are not present in the 1988 catalog. I have several of the 400 series meters, and a 3400. Reliable and useful, plus they look cool on the bench.
I have the 400EL which is nice as it goes up to 10 MHz; it has a BNC front panel connection.
HP was so lovable in those days! The way they designed and built stuff. Nothing like it. (Except Tektronix!)
This HP 400F AC Voltmeter was purchased in 1972.
Another great find. The only tricky bit will be the meter calibration screw.
The only thing I found on ebay was the service manual for one at £13.27 plus £12.33 shipping. LOL
I picked up a 400E at a Ham Flea Market last year. Got it because it is HP and has NASA/JPL asset tags on it. I figure given the vintage status it could have been used for Apollo work.
I started to replace the HP power cord jack with a standard IEC jack. Drilled out the connector - wires dangling still. Need to finish it. Too many projects at once...
Would sure love to have a hp vom! (I know this is only a ac voltmeter) Looking forward to the next part! Thank you!
I saw "7152" on one of the sprague caps towards the back, so possibly a 1972 build date? That would mean HP sold these things for at least six or seven years
Nice....cheers.
Hey Andy, Don't forget Mr Brown 22.05.
@@frankowalker4662 Ta
oh carleton, neat. i wrote my thesis there, though not in engineering
I used one of those meters to do signal-to-noise measurements for communications equipment. I don't recall the one I used had a switchable filter, though.
I have the 400 E model and it works good. 400 E goes to 10 megacycles.
Carleton grad here! Computer Science though, not engineering.
My 400GL meter needle rests below zero with power off. I believe that's normal and per design. Once power is on, needle will come up and rest at 0
My guess….. it will be perfect at the end of the 3rd video, and some of us will learn something.
That is from 1969... can tell from the serial number.
Hi, that's funny, I was looking at this exact meter on Ebay, but ended up buying the 3400 model 😂
Edit: A mechanical 0 setting will have a broken pin on the gear disc, the poor guy had to suffer when he got his hand bent like that
Nice day 🙂 Tom
Have one also, works great
Hello I have the FL version of this meter. There is nothing wrong with needle the meters are sealed. Mine sets below the zero just like yours. 73 Lawrence KF4HNF.
This is true for the FL version. It has a logarithmic meter movement (dB scale is linear, but voltage scale is log.) in that case, zero volts is actually negative infinity dB, so there is no zero adjustment screw, and the meter reads off scale to the left with no input. The 400F (without the L) has a zero adjustment screw, and the meter should read zero when the unit is turned off. It may read slightly above zero when on, of course, due to the high input impedance.
i love your videos but jesus what did paul carlson do to hurt you lmao
Wonder why somebody put a sticker saying "poob" upside-down on this...
my hand writing is total crap.
@@cashewmilkfan didn't expect to get a reply from the actual author of that note XD
Poob means good in Canada 😂
Hah, I personally just got a 3400A. Jinx.
you might be able to super glue a nub onto the meter cal screw and turn it from there.
Score!
Get a HP manual for the instrument, stop guessing
No dim bulb, no variac ==>> yes. Way over used technique for many items.
Sure hope that meter movement is recoverable, really got whacked.
Real men don't use Dim Bulbs !
@@andymouse lol correcct