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 Post subject: Beckman / Berkeley 7000 Series EPUT Meters
PostPosted: Aug Mon 29, 2016 6:06 am 
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Hello All,
I have a question about the venerable Beckman / Berkeley 7000(?) Series EPUT Meters. I owned one way back in 1975, when I was in high school. These EPUT meters were the state of the art frequency counters (and event counters) of their day, new in 1958. They were obsolete even in 1975, but they were a wonderful 1950s design to behold. They could only count up to 1 MHz (999,999 cps), but mine also had the heterodyne down-mixing chassis, so it was able to count frequencies up to 51 MHz (50,999,999 cps). This was accomplished by mixing the desired RF signal to be measured with the proper LO signal, which was selected by a huge mechanical wheel of tuned circuits. If I remember correctly, the 10 MHz time-base was divided down to 1 MHz and run into saturation to generate harmonics. The tuning wheel had a 1 MHz position, at 2 MHz position, a 3 MHz position, etc. all the way up to 50 MHz, each position having a tuned parallel LC circuit to select the proper harmonic. This LO was applied to a mixer and the difference frequency was then sent into the EPUT Meter (Events per Unit Time). You cranked the wheel until you got a non-zero reading on the EPUT Meter. Quite a Rube Goldberg approach by today's standards, but it worked. The mechanics were great. Too bad my mom threw all this out after I went off to college and into the job market. (It was my fault for not retrieving any of it for over a decade.)

Anyway, here is my question: As I recall, the vacuum-tube plug-in decade counter units in the main EPUT meter were based on some sort of base-eight or base twelve logic concept involving vacuum tube flip-flops. There was a nice and elaborate write-up on how this all worked in the service manual, another wonderful thing about test equipment from that era. Does anyone have a write-up or recall how this worked (Theory of Operation)? I can't recall the exact model number and any service manuals that I had are long-gone. I was curious as to why Base 12 (or was it Base 8?) was used. I'm pretty sure it was Base 12. Weird!

Best Regards,
Bill WDCVG


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 Post subject: Re: Beckman / Berkeley 7000 Series EPUT Meters
PostPosted: Aug Tue 30, 2016 2:56 am 
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ok this is a shot in the dark but maybe this is kinda / sorta related to the info you are looking for:
Attachment:
GR-DecimalCountingUnit.jpg
GR-DecimalCountingUnit.jpg [ 48.92 KiB | Viewed 3745 times ]


I know this is not Beckman (that literature is hard to find on the net). Instead this is an extract from the General Radio Experimenter article in May 1961 about the then 'new' 10Mhz counter they finally got around to producing, the model 1130a

The article goes on to explain the I.E. Grosdoff was able to change the scale-of-16 back to a scale-of-ten system by using feedback circuits. (Of course all this had been implemented in the previous decade by Beckman and HP in numerous counters and EPUT units, but for GR what's the rush :roll: ). The articles shows how that's done.

If any of this is barking up the right tree, you might find this an interesting read.
http://www.ietlabs.com/pdf/GR_Experimen ... y_1961.pdf

Then there is also the HP AC-4 manuals you might track down. The AC-4 counter modules are similar to what Beckman used This link has the manual AC-4 online that gives more info

http://nixiebunny.com/hpac4/

Interesting stuff.

HTH,
Grid2


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 Post subject: Re: Beckman / Berkeley 7000 Series EPUT Meters
PostPosted: Aug Tue 30, 2016 3:14 am 
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Found some photos of the Beckman/Berkley 7170 which my photo notes say is a10Mhz counter :
Attachment:
7170_10Mhz_p1_r.jpg
7170_10Mhz_p1_r.jpg [ 38.78 KiB | Viewed 3744 times ]

Attachment:
7170_10Mhz_p2_r.jpg
7170_10Mhz_p2_r.jpg [ 57.09 KiB | Viewed 3744 times ]

Attachment:
7170_10Mhz_p3_r.jpg
7170_10Mhz_p3_r.jpg [ 42.1 KiB | Viewed 3744 times ]


Perhaps similar to yours... happy memories :)

Cheers,
Grid2


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 Post subject: Re: Beckman / Berkeley 7000 Series EPUT Meters
PostPosted: Aug Tue 30, 2016 3:42 am 
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Wow, EPUT meter, I haven't heard that term since I went to the local college electronics lab with my ST-6 RTTY filters and discriminators. I used their EPUT meter and an oscillator to align the filters/discriminators. I would not doubt these old counters have gone to elecronics heaven years ago but the ST-6 remains, still works!

Chas

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 Post subject: Re: Beckman / Berkeley 7000 Series EPUT Meters
PostPosted: Aug Tue 30, 2016 4:16 am 
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Bill, I have a fair photocopy of the manual for the Beckman models 7350 and 7360 Universal EPUT and Timer. The Decimal Counting Units (DCU) are described in separate addenda, one for the model 775 DCU and one for the model 785. The model 775 DCU manual describes the "scale of ten" this way: "four binaries are connected in cascade forming a scale-of-16 which is permuted to a scale-of-10 by two positive feedback paths."

The resulting counting sequence is quite odd: 0 1 2 3 6 7 12 13 14 15. Perhaps that odd sequence with a jump to 6 and then a jump to 12 is what you recall.

Some other counters such as the TTL 7490 are "bi-quinary" counters - a divide-by-two binary followed by a divide-by-five counter. I don't know if any tube counter used a bi-quinary sequence, but perhaps that might be the term you are remembering?

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 Post subject: Re: Beckman / Berkeley 7000 Series EPUT Meters
PostPosted: Aug Tue 30, 2016 10:31 am 
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Hello All,
Thanks for the nice replies and photos! As you can imagine, I have some very fond memories of playing with the EPUT Meter. The unit I had was probably the Model 7360 Universal EPUT and Timer, with the 50 MHz down-mixer.

I also acquired about 7 relay racks of 1950s and 1960s test equipment when I was 16 years old. (See attached Word.doc) MIT Lincoln Laboratory had just shut down their Radar Astronomy Station near El Campo, Texas and I knew the technicians who worked there. I used the money I made from working after school as a TV repairman to buy used test gear -- the stuff they didn't deem worthy to send back to Lexington. I bought a Panoramic Panadapter for my shortwave receiver, an AMPEX 7 track reel-to-reel instrumentation-grade tape recorder, and an old BC-610-I. I even bought a 40 GHz (yes, 40 GHz with a G) spectrum analyzer that still works. It has a klystron for the 1st LO to work up that high. Quite a mechanical marvel of tuning with a spiral clamshell gear. But again, all of this was pretty much obsolete in 1975.

"The resulting counting sequence is quite odd: 0 1 2 3 6 7 12 13 14 15. Perhaps that odd sequence with a jump to 6 and then a jump to 12 is what you recall... Some other counters such as the TTL 7490 are "bi-quinary" counters - a divide-by-two binary followed by a divide-by-five counter. I don't know if any tube counter used a bi-quinary sequence, but perhaps that might be the term you are remembering?"

Hi Steve Byan,
You may have hit the nail on the head: I do find that sequence quite odd and perhaps that's what I'm remembering. I guess it all makes sense if you're designing counting circuits with vacuum tube flip-flops, and you want to save a tube here and there in the design.

If I recall correctly, there was a star shape around some of the numbers in the manual which signified something very significant about the way it counted and handed off the carry pulse to the next DCU up the chain.

I still remember the smell of dust burning off of hundreds of vacuum tubes that glowed in the dark. My mom was super to let me fill my room with all of that stuff and put up with an increase in the electric bill.

Bill WD5CVG


Attachments:
El Campo Test Equipment.doc [237.5 KiB]
Downloaded 79 times
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 Post subject: Re: Beckman / Berkeley 7000 Series EPUT Meters
PostPosted: Aug Tue 30, 2016 1:06 pm 
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The starred numbers sound familiar, but I didn't see any during a second look at the DCU manuals. I did find something interesting in the description of the higher-speed 785 DCU. It uses a different setup than the slower 775's. The manual describes its scale-of-ten thusly: "three binaries are connected in cascade to form a scale of eight. A fourth binary is arranged to block the input to the second binary during two input pulses to the counter, so that ten rather than eight pulses are required to produce a complete cycle."

Sorry I can't spare the time to scan the manual right now.

That's a nice pile of gear! It must have been great fun to play with.

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 Post subject: Re: Beckman / Berkeley 7000 Series EPUT Meters
PostPosted: Aug Wed 31, 2016 1:14 am 
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Quote:
The unit I had was probably the Model 7360 Universal EPUT and Timer, with the 50 MHz down-mixer.

Here's some 7360 photos. OMG look at all those 5963s! :)

Attachment:
7360_10Mhz_front_r.jpg
7360_10Mhz_front_r.jpg [ 51.75 KiB | Viewed 3693 times ]

Attachment:
7360_10Mhz_interior_r.jpg
7360_10Mhz_interior_r.jpg [ 97.18 KiB | Viewed 3693 times ]


Cheers,
Grid2


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 Post subject: Re: Beckman / Berkeley 7000 Series EPUT Meters
PostPosted: Aug Wed 31, 2016 2:58 am 
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The picture of the 7360 looks familiar; I believe that's the one I have in storage. It didn't work when I got it years ago and I had to replace a number of the caps in the display plugin units that were leaking. They looked like micas but I don't think they were.


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 Post subject: Re: Beckman / Berkeley 7000 Series EPUT Meters
PostPosted: Aug Wed 31, 2016 3:49 am 
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Location: Albuquerque, NM 87123
I have a Berkeley 554:


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 Post subject: Re: Beckman / Berkeley 7000 Series EPUT Meters
PostPosted: Aug Wed 31, 2016 5:46 am 
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I have a couple of those display modules that I got off of Ebay. I was thinking of using LEDs in them instead of the neon bulbs. I want to try some different colors.

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 Post subject: Re: Beckman / Berkeley 7000 Series EPUT Meters
PostPosted: Aug Wed 31, 2016 7:16 am 
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Strange........That interior view looks exactly like my Beckman 7360, as if the middle photo, which I have posted here before, were cropped and rotated.

Image

Image

Image

Note that the 7360 is a 1mHz counter. There was another version with 2mHz capability.

I also have a portable Beckman 5230B.

http://www.radiomuseum.org/r/bekman_ins ... _eput.html


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 Post subject: Re: Beckman / Berkeley 7000 Series EPUT Meters
PostPosted: Aug Wed 31, 2016 8:32 am 
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Wow! There are a lot of really nice EPUT Meters out there!

Yes, the whirring of all of those fans and the soft glow of the tubes in the dark of night. The oscilloscope traces sweeping across the screen. The smell of burning dust. The sounds of tuning around the shortwave bands and listening to weird utility stations popping up on the Panoramic Panadapter. What memories! Nerd heaven!

Bill WD5CVG


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 Post subject: Re: Beckman / Berkeley 7000 Series EPUT Meters
PostPosted: Aug Wed 31, 2016 4:34 pm 
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There is a whole chapter on counting (with tube circuits) in Pulse and Digital Circuits by Millman and Taub. Used copies of this book are dirt cheap plus $4 shipping from Amazon.. Highly recommended !

https://www.amazon.com/gp/offer-listing ... 366&sr=1-1

-Chuck K7MCG

PS: Their later book, Pulse, Digital and Switching Waveforms treats discrete transistor circuits. Also recommended.


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 Post subject: Re: Beckman / Berkeley 7000 Series EPUT Meters
PostPosted: Apr Fri 26, 2019 9:25 pm 
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Location: Opelika, AL
I have been fascinated by these since I first saw one in physics class in high school. The physics room was all the way on the 4th floor (it's own little spot at the top of a single staircase) They were basically in the attic, so had all kinds of good loot like this that someone had brought upstairs, and nobody wanted to bring down stairs again :)

I had always hoped to be around when they finally decided it had to go... maybe it's still up there? I took two physics classes so I could get to muck about with this stuff a second time. The nuclear physics section of the class was my favorite, mostly because it was then the old tube powered gear got dragged out to hook up to the geiger mueller tubes. good times.

Thanks Chuck for the book recommendation, I just ordered a copy to add to my to read pile.

I would like to put in a request that if some one other than steve byan has manuals that they could scan, I'd love to put that info out there for other curious minds. Steve is going to try to get his scanned and send to me. I will try to organize in a .pdf and post to BAMA or elsewhere. If there is other info out there on these specific machines, I'd love to see it.

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 Post subject: Re: Beckman / Berkeley 7000 Series EPUT Meters
PostPosted: May Fri 31, 2019 10:37 pm 
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OK, the manual is up on my site. It's still missing one page, the parts list for the Decimal Counting Unit schematic. I'll get that inserted next week. In the meantime, please don't upload the manual elsewhere, until I add the missing page.

The sheet feeder on the scanner might have skipped a page or two. Let me know if you notice anything missing.

https://www.byan-roper.org/steve/manual ... 0Timer.pdf

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 Post subject: Re: Beckman / Berkeley 7000 Series EPUT Meters
PostPosted: Jun Sat 01, 2019 2:45 am 
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Hi Steve,
Thanks very much for going to the trouble to scan and post the Manual! It brings back such fond memories.

In this modern age, we can really appreciate the trouble and effort that they had to go to in order to produce a Manual with drawings and schematics -- all typed out by secretaries on a manual typewriter for the original, and all drawings and schematics done by hand by draftsmen.

Best Regards,
Bill WD5CVG
(FYI, it looks like page #3-12 and pages 5, 6, and 7 of the Supplementary Service Notes are missing. Also, it looks like pages 1 - 3, 5 - 7, and 9 - 11 of the Model 785 Decimal Counting Unit are missing.)


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 Post subject: Re: Beckman / Berkeley 7000 Series EPUT Meters
PostPosted: Jun Sat 01, 2019 4:48 am 
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Awesome, thanks! I got the book you recommended, but have been swamped with other things and haven’t had time to read yet. Looking forward to digging through this manual soon!

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 Post subject: Re: Beckman / Berkeley 7000 Series EPUT Meters
PostPosted: Jun Sat 01, 2019 5:47 pm 
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I had a 7360 in my shop and it only went to 1 MHz. I built a 785 plugin myself and then had 10 MHz capability. (As a sidelight, when I fired up the newly built DCU it didn't work. I figured in a 10 tube circuit I had made a wiring error but as it turned out, one of the 1N914 diodes had been marked in reverse. Finding that was quite a job, and a new diode made the unit work as designed.)

That didn't last too long, as I acquired an HP 524B shortly. I no longer needed the 7360. I was using these to adjust frequeny of marine radio transmitters. I had a couple of HQ-129-X receivers to calibrate the time bases against WWV.

These days WWV hasn't been very useful. I recently acquired a rubidium oscillator so now have no need to receive radio signals for calibration. Propagation has been so poor that I couldn't satisfactorily zero beat my oscillator with the incoming signal.

And my venerable BC-221 is surplus to my needs.


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 Post subject: Re: Beckman / Berkeley 7000 Series EPUT Meters
PostPosted: Jun Sat 01, 2019 8:24 pm 
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WD5CVG wrote:
(FYI, it looks like page #3-12 and pages 5, 6, and 7 of the Supplementary Service Notes are missing. Also, it looks like pages 1 - 3, 5 - 7, and 9 - 11 of the Model 785 Decimal Counting Unit are missing.)

Thanks Bill. I didn't have time to proofread it on Friday afternoon. It's disappointing the sheet feeder missed so many pages. I'll scan the missing ones next week.

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