How on earth a $50 vintage frequency counter looks like ? - Page 1
Forum section: electronics / general

author: BravoV
author_rank: Super Contributor
timestamp: September 28, 2011, 08:56:33 am
content: Just grabbed this beauty from a local surplus shop for about $50 US, not bad huh.Powered on properly, no problem with the display, still bright & sharp and all buttons are working perfectly. Since there was no proper freq. reference back there, it was tested straight at the power AC line from a step-down transformer and showed 49.999 Hz, our power main freq is 50 Hz and no further testing was done at the shop.Rust at the screws are showing clearly it's age, wonder what year it was made ? No label nor sticker for the hint either.Adjustment hole, wonder how far the internal reference is drifted.Tear down ? Hell yeah, just be patience folks, will do a complete tear down and also will run a freq. test against my agilent multimeter.Stay tune.

author: FreeThinker
author_rank: Frequent Contributor
timestamp: September 28, 2011, 12:14:09 pm
content: Nice! Lucky sod. My guess would be mid eighty's judging by the case but I could be way off. Sometimes the serial number can give you a clue 089 week 0 1989? seems a little late for my gut feeling but maybe it was a legacy model still in production. Do you need a frequency counter or are you like me and can't resist sad puppy eyes and had to give it a home?

author: amspire
author_rank: Super Contributor
timestamp: September 28, 2011, 01:05:43 pm
content: I think it was from the late 70's, but if you open it up, you will see date stamps on the IC's.The manual, including schematic is available, if you need it.http://www.eserviceinfo.com/downloadsm/31091/Leader_LDC-823_823S.htmlI am puzzled how you measured 49.999 Hz, as I thought the longest gate time was 10 secs which gives 0.1 Hz resolution. Did you measure period and invert? Or have Leader done something really clever to get the extra 2 digits of resolution in a 10 sec gate period?My understanding is that this is before the era when counters got microprocessors allowing them to speed up measurements at full accuracy.Richard.

author: ejeffrey
author_rank: Super Contributor
timestamp: September 28, 2011, 02:43:41 pm
content: Reciprocal counting in discrete logic? Remember: if brute force doesn't work you aren't using enough.

author: FreeThinker
author_rank: Frequent Contributor
timestamp: September 28, 2011, 02:59:52 pm
content: RE Discrete logicTTL does NOT mean Trust To Luck.A Flip Flop is not a form of footwearRace Hazards are not a F1 pile up (and finally)Slew Rate is not how fast you can get drunk.Remember this kiddies and you will not go far wrong

author: BravoV
author_rank: Super Contributor
timestamp: September 29, 2011, 02:39:58 am
content: Quote from: FreeThinker on September 28, 2011, 12:14:09 pmThanks, yeah, that is pure luck and really exciting moment when I saw it and knew the price tagMy need for freq counter currently is covered and enough with my current agilent multimeter, so yes, its the impulse on giving this really bright shinning eyes (display) puppy a home, don't you ? Not sure these days, I guess youngster especially the 'just use microprocessor at everything' generation can not fully appreciate this kinda classic beauty.Quote from: amspire on September 28, 2011, 01:05:43 pmYou're right, thats a mistype, its the moment that I when powered up when I saw the 49.9, I knew this thing is still alive and still acurate considering it's age. It was a really exciting moment.Anyway, thanks Richard for the heads up on that link, I was about to visit that site too for service manual, and just downloaded it, took a brief look at it and YES !!!!its a pure discretes built counter, just check it out yourself at few last pages, it has the full schematic in there.Quote from: FreeThinker on September 28, 2011, 02:59:52 pmHa..ha.. I got one .... Psychiatrist is not needed even they're a confirmed bi-polar

author: FreeThinker
author_rank: Frequent Contributor
timestamp: September 29, 2011, 09:45:25 pm
content: @Bravo< My need for freq counter currently is covered and enough with my current agilent multimeter, so yes, its the impulse on giving this really bright shinning eyes (display) puppy a home, don't you ? Not sure these days, I guess youngster especially the 'just use microprocessor at everything' generation can not fully appreciate this kinda classic beauty.>Yep! Got myself a frequency counter purely because it had a nixie tube display. Its in a box under the stairs at the moment (The black hole every home has one) .Can't remember any thing about it except those wonderful dancing neon numbers, must dig it out and have a play again.

author: Hypernova
author_rank: Unknown
timestamp: September 30, 2011, 12:49:27 am
content: Those BNC headers are in pretty bad shape, might want to replace them ASAP.

author: BravoV
author_rank: Super Contributor
timestamp: September 30, 2011, 01:51:24 am
content: Quote from: FreeThinker on September 29, 2011, 09:45:25 pmNixie tubes, that is even better than my VFD, must be really nice ! Please, if you had the chance, make a new thread and post lots of pics, I'd love to see it.Quote from: Hypernova on September 30, 2011, 12:49:27 amYep, those rusty components will be replaced once I do the complete teardown and clean-up, don't have any clue how thick the dust gathered inside.This kind of vintage gadget tear down & clean-up might take lots of time and energy, its just currently I don't feel like to commit on it yet, lack of spare time.Probably just for curiosity, maybe I will just open up to take a peek briefly inside, stay tune, will post more pics here.

author: grenert
author_rank: Frequent Contributor
timestamp: September 30, 2011, 02:37:38 am
content: I have the same affliction: I'm not a radio guy and don't have a good use for frequency counter, but the LEDs called out to me! I have an HP 5315A. It's the same reason I have an HP 3456B when it is probably not as good as most modern handheld DMMs.It must be because I started off with LED calculators!

author: BravoV
author_rank: Super Contributor
timestamp: September 30, 2011, 03:00:32 am
content: Quote from: grenert on September 30, 2011, 02:37:38 amThough I'm not the expert on this, I believe your HP 5315A if it has an external reference clock connection, these oldies dinosaur freq counters like ours will beat those hand held freq counter out of the water if coupled with external accurate clock reference such as rubidium oscillator. Someone correct me if I'm wrong.Not sure when, but its very likely once I finished cleaning up this gem, probably I will buy those cheap used but re-calibrated atomic rubidium 10 Mhz reference that are plenty out there like at ebay, and hook it to the bnc connector shown at the rear shot picture above and surely they will have a new life and far better accuracy than before.Btw, you should share yours too please.

author: amspire
author_rank: Super Contributor
timestamp: September 30, 2011, 03:20:00 am
content: Quote from: grenert on September 30, 2011, 02:37:38 amI almost choked when I read this.The HP 3456B not as good as most modern handheld multimeters! Where do you get these handheld multimeters with 0.003% accuracy that can also can do 4 digit readings at 6000 readings/sec? I must be looking in the wrong places.Ok - I admit when you are using the HP 3456B as a handheld multimeter, then it gets a bit tiring, and dragging around that extension cord is hard work. And I forgot - no transistor tester!!!!!!!Also your HP 5314A is historically a hugely important counter. As far as I know, t was the first to measure frequency by measuring the period of multiple cycles and calculating the frequency from that. Everybody does it now, but not when the H 5315A came out. As a result, with a 1 second gate, it can give at least 6+ digit accuracy for any frequency - something which none of the preceding counters could do. Also its measurement versatility with the A/B channels still kills many of the modern counters.I would feel pretty happy with that combination myself.Richard

author: BravoV
author_rank: Super Contributor
timestamp: September 30, 2011, 04:07:43 am
content: Quote from: amspire on September 30, 2011, 03:20:00 amI concur, especially this feature mentioned above, since both channels sourced from single reference internally, for freq difference calculation/comparison, I believe no hand held can beat this powerful feature, simply hands down.

author: grenert
author_rank: Frequent Contributor
timestamp: September 30, 2011, 05:22:50 am
content: Quote from: amspire on September 30, 2011, 03:20:00 amOh, Richard, you are absolutely right! I have the 345X series on my mind because I was looking for a 3457A. What a difference one digit makes! My HP DMM is the lowly 3476B: A whopping 3.5 digits and something like 0.3% accuracy. On the plus side, I replaced the NiCads, so I can go cordless nowI have to admit, those HP engineers of old really were thoughtful about the design of even the most lowly equipment. Here is an old HP Journal describing the full line of DMMs circa 1977:www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1977-02.pdfThis 1979 issue describes all of the innovations in the 531X counter series:www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1979-01.pdf

author: amspire
author_rank: Super Contributor
timestamp: September 30, 2011, 05:58:45 am
content: It all makes sense now. The less said, the better about the HP 3476B.Except these people think they can sell it for almost $1000:http://www.testequipmentconnection.com/1821/Agilent_3476B.phpThey describe it as a "DIGITAL MULTIMETER 300 Mhz Compact HP Autoranging DMM".300MHz ! - is there something you aren't telling us about the 3476B?Anyway if you are interested in your counter, the HP Journal article is an interesting one:http://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1979-01.pdfIt looks like it is not the first reciprocal counter - HP used the method in the 9 digit 5345A counter by using a lot of heavy duty ecl and custom chips.The 5315A was the first one using a custom LSI chip to do the job affordably and in a compact case.Richard

author: Zero999
author_rank: Super Contributor
timestamp: September 30, 2011, 08:48:46 pm
content: It looks like you've paid a fair price for it. It's not a bargain but you've not been ripped off either.A frequency counter is an invaluable tool, especially when working with MCUs of RF when you need decent accuracy. You get much better accuracy and a higher frequency rance than a 'scope.I have an old frequency counter I got form work awhile ago. I can't remember the brand but it was made in the mid 80s. It works up to 1.3GHz and is still as accurate now as it was when I first got it. Nowadays you can buy a frequency counter which works at over 2GHz with decent accuracy pretty cheaply.

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: September 30, 2011, 11:18:44 pm
content: Oh those LEADERLeader LDC-831 Frequency CounterFrequency Ranges:HI (1M ~ 150M)LO (5Hz ~ 2M)Gate Times:0.01S and 1SDisplay in green LEDaccessories: mains adapter / probe

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: September 30, 2011, 11:20:53 pm
content: LDC 823A ... here is your Users Manual

author: Bored@Work
author_rank: Super Contributor
timestamp: September 30, 2011, 11:43:07 pm
content: Thatis of course not a 170 MHz probe for a frequency counter. It is an RF voltage probe. And since it contains a germanium diode for signal rectification it is probably the worst probe to use with a frequency counter.It is obvious the image was taken from somewhere on the web, probably from herehttp://www.helmut-singer.de/img/elmes20962.jpgand a story was made up.

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: October 01, 2011, 01:45:03 am
content: Quote from: BoredAtWork on September 30, 2011, 11:43:07 pmI will pay for all the damages if there is any ...But I cannot do anything for the brain damaged like you !!