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Re: Cutting edge GM counter (1953)

Posted: Tue Jun 25, 2019 6:36 am
by Rex Allers
Wow. I, at first, thought you were linking the GM counter manual.

All about neon lamps, 1966. Really cool, man. More than 100 pages. I'll have to digest it slowly.

One comment. I wish the guy that wrote the (pencil?) notes in it had better handwriting. Looks like good additions.

As for the Eveready reply. I don't want to get into, "Hey, you kids, get off my grass", mode, so I'll just let it pass.

Re: Cutting edge GM counter (1953)

Posted: Tue Jun 25, 2019 8:52 pm
by Rich Feldman
My first and only 90 volt battery was pretty old stock in about 1970.

Dad had taken me to J & H Outlet store in San Carlos. There we found all the parts
for a neon glow lamp blinker (relaxation oscillator) circuit in an already-old magazine or book.
Don't know if I've ever gotten an electric shock from a battery after that one.

Re: Cutting edge GM counter (1953)

Posted: Wed Jun 26, 2019 5:10 am
by Richard Hull
Be glad you didn't stumble onto the 510 volt battery. It could supply a few milliamps! I laid eyes on a 510v batt in Batteries Plus. They have recessed, flat, silver-plated pad contacts. (see previous photo) When new, they are covered with a plastic insulating film. When placed into service, the battery door has a spring that forces the top of the battery into spike contacts in the photo flash battery holder. These pierced the film to make contact.

I have been shocked by the naked button contacts on the 90 volt jobs when a young boy...WOW!...DC is nasty. If you are at all sweaty the 67.5 volt battery will ring the old bell, too.

Richard Hull

Re: Cutting edge GM counter (1953)

Posted: Wed Jul 17, 2019 2:06 am
by Richard Hull
Finally!! It took a few weeks, but apparently Eveready had someone go down to the sub-basement nether regions to talk to the "old retainer" sitting at the slant top desk with his green head visor on. Eveready stopped production of a all stack cell carbon-zinc high voltage batteries in 2011. Now you know and can talk with authority on the demise of those old portable vacuum tube application batteries of yesteryear.

Richard Hull

Re: Cutting edge GM counter (1953)

Posted: Fri Oct 11, 2019 5:42 pm
by Mark Rowley
I’m a bit late on this thread but wanted to say that restoration of 1950’s geiger and scintillation detectors has been a years long hobby as well. Detectrons, PRI’s, RCA, Babbel, and Mt Sopris are just a few of my favorite detectors. Without disrupting the originality of the unit, i make it a point to assemble replacement power supplies to negate the use of unobtanium B batteries or the 22.5v versions.

The photo is just a small sampling of my PRI 111B stock. The YouTube link is a refurbished 1954 PRI 111 Scintillator which uses 2 D cells and four 9v’s to operate.

https://youtu.be/D4Nydiq10aE

Mark Rowley

Re: Cutting edge GM counter (1953)

Posted: Fri Oct 11, 2019 8:21 pm
by Richard Hull
Wow! Bill Kolb and I love those old precision "ray gun" scintillators!! Nice work. All of my restorations also use home built B battery eliminators. I have done several of the precision chrome plated GM restorations as well as some Nuclear Chicago GM counters and ion guns (ala cutie pie)

Richard Hull

Re: Cutting edge GM counter (1953)

Posted: Sat Oct 12, 2019 12:00 am
by Mark Rowley
Providing you have yet to see it, you may like this. It’s a 12 minute “commercial” made by PRI in 1955. It primarily focuses on the benefits of the “Ray Gun” Scintillator (aka 111/111B) with no shortage of action shots.

https://youtu.be/fCdB1Wdc5VI

Mark Rowley

Re: Cutting edge GM counter (1953)

Posted: Sat Oct 12, 2019 3:29 pm
by Richard Hull
Thanks for the URL. I have passed it on to Bill Kolb and others. A great little short promo film. I noticed three things.

1. I noticed the little tiny Crosley auto in the film. Rare and worth a fortune today.
2. The voice of the narrator was that of the man who introduced and gave demos at the beginning of every episode of Science Fiction theater 1955-57 TV show that I watched religiously as a young man.
3. Did you see the credits at the end of the film? Mc Gowan was the producer/director. Ever read the book “Uranium Fever or No Talk under a Million” by Raymond and Sam Taylor? Mc Gowan is the director from Warner Brothers who Raymond and Sam Taylor worked with through the bulk of the book to produce a feature length film about the U boom, which was a nightmare. Mc Gowan is portrayed as a nail biting, paranoid nervous Nellie who was freaking out constantly during the filming. The Montgomery fellow in the credits was also part of the film crew in the book.

Richard Hull

Re: Cutting edge GM counter (1953)

Posted: Sat Oct 12, 2019 10:13 pm
by Bob Reite
I remember getting a PRI 111 in an Olson Electronics $5.00 "surprise box". Alas it was missing the PMT and the attached crystal, the most expensive parts. I don't recall what became of it, probably traded it or sold it at a hamfest ages ago.

Re: Cutting edge GM counter (1953)

Posted: Sat Oct 12, 2019 11:38 pm
by Mark Rowley
Around 1998 / 1999 Allyn Goshy and a couple others obtained quite a few 111/111B units and refurbished them with battery eliminator supplies (Goshy being the most famous imo). Due to the scarcity of geiger counters in the public market coupled with the Y2K fear, I saw these being sold for $500-$1000 a piece. $500 may have been the price to send in an unrefurbished version for upgrading. Sales appeared to taper off around 2002 or 2003. Today, unrefurbished units tend to sell between $50 and $150.

I have several of the Goshy supplies and I have to complement him on his work. Hand wound transformers and personally designed circuitry. Something of a rarity these days.

The 111's are generally sought after by Star Trek prop collectors as they were featured in one or two episodes. Sadly though, when the prop folks get them they are quicky gutted like a trout and spray painted flat Krylon silver.

Mark Rowley

Re: Cutting edge GM counter (1953)

Posted: Sun Oct 13, 2019 2:02 am
by Richard Hull
Like Bob, I obtained a gutted "Tower" brand work alike111 (Sears and Roebuck's house brand made by El Tronics). El Tronics made a near carbon copy of the precision 111 scintillator. Sears got into all the fads and created house rebranding of normal products. They sold Henry J autos for a few years as their "Allstate Six" Those who know Sears products will remember that all their automotive products, batteries, tires, etc., are all "Allstate" house brands.

I took just the ray gun and tossed the battery pack and electronics and turned it into a GM counter over 25 years ago. I kept the meter and on-off, range switches and placed a 5979 GM tube in the snout, boring a 1" hole in the end to expose the mica window. It still functions and uses a small 9 volt transistor battery and a little 1" speaker. All circuitry is stuffed into the large round rear chamber of the gun. I find it difficult to believe the battery I put in the counter still working after 7 years in the gun as I just took these two images after pulling it out of storage.

Re: Cutting edge GM counter (1953)

Posted: Sun Oct 13, 2019 4:01 am
by Mark Rowley
The ElTronics PR31! I just restored one a year ago August. Those are fun to work on. Unlike the subminiature laden PRI’s, the PR31 uses a 1U4 and three 1U5’s. Performance wise, the PRI seem to be better and more stable. On the bench are also three Detectron DS234 Scintillator guns. I’ve yet to restore them but I may do so next year. If they perform anything like the lunchbox DS-222 or DS-277 scints, the PRI’s may have a contender.

A Facebook friend builds small modules which incorporate a HV driver and a pulse amplifier. It’s even compatible with an MCA and easily powered by 5v. I’ve been planning on gutting one of the more distressed 111B’s and modernizing it with one of these modules. Who knows when I’ll get to doing it, but it’d be a fun project similar to yours.

Mark Rowley

Re: Cutting edge GM counter (1953)

Posted: Mon Oct 14, 2019 8:45 pm
by Roberto Ferrari
In my small collection, I have a Isoto, built in Argentina during the 70's. Copy of a French design.
Unfortunately I have no schematics to attempt to rebuild it.
F.jpg

Re: Cutting edge GM counter (1953)

Posted: Mon Oct 14, 2019 11:30 pm
by Mark Rowley
Hi Roberto,
I have two of the French SPP2 versions and have noticed they are more or less modern versions of the PRI 111 detectors except that they have the audio squealer function (similar to how a classic metal detector sounds when getting close to a metallic object). Based upon your picture, the main box has some differences which makes me think the circuity may be different than the SPP2.

Hopefully the design of yours follows the modular arrangement found inside the French version. It makes for very easy disassembly as well as easier tech work. Fixing any malfunctions should be fairly straightforward.

Somewhere in my files I have the schematic for the SPP2. Let me know if you think it'd help. I can forward you a copy.

Mark Rowley

Re: Cutting edge GM counter (1953)

Posted: Tue Oct 15, 2019 1:34 am
by Richard Hull
My repairs/rebuilds do not have to save the patient's internals or respect the original purity of circuitry contained within. If the patient is more dead than alive, I tend to gut the circuitry and update all circuitry to a more modern standard. What is important is to at least attempt to maintain the original outward appearance and calibration. This is easily accomplished in 99% of what I do. I make every attempt to save the vacuum tube identity of the device. But, sometime the old circuitry just will not respond especially if the circuitry is too tightly packed in or the 25-50 henry boost HV choke is shot. Most of the time when this key component is bad, it is due to battery juices and vapors getting in or settling on the 2000 turns of #56 or #68 AWG windings in the choke and corroding many opens in the turns. 90 percent of the GM and scintillator issues are HV related and or B battery elimination issues. Filaments can remain lit as always, ("D" cells). I tend to check the old tube circuitry by putting the usual 120 volts on the HV oscillator by just clipping in a variable 0-150 volt DC supply. If the counter comes to life, it is just a matter of installing a good, tiny, home made B battery eliminator board and a new lower voltage battery to power this add on. Usually there is a ton of room ready made in the old hollow for the two B batteries.

From my standpoint I desire a look-alike, work-alike restoration via the easiest and most reliable path. By gutting 100% of the tube circuitry and replacing it with the latest circuitry, I find you have enough room in the typical old counter to build an entire rad lab inside. Each job is unique for me.

It is rare for me to be approached by someone wishing a full flawless restoration with no alterations in an old counter. It does happen, but they need to check their pacemaker as it will not be cheap. One recent restoration had me creating a small bass wood frame with beveled corners and pasting on the old original battery printed labels with a small battery and miniature boost board inserted within which looks just like the original eveready or burgess B battery which snaps into the original battery clips. Got $450.00 for that one. The counter needed no work other than cosmetics. The customer knew what he wanted and had the cash to pay for it.

I have very tiny battery eliminators that I have designed, but I attach, here, an image of my combo install board normally inserted in many tube systems. Not only does it eliminate the B battery, it also supplies GM tube voltages variable from 400 volts to about 900 volts, as well as outputs a positive or negative prefect square wave pulse from the tube of 50us width.

Re: Cutting edge GM counter (1953)

Posted: Tue Oct 15, 2019 3:30 am
by Mark Rowley
Impressive! Doubt I'll progress to making my own circuit boards but who knows, retirement has been an interesting road so far.
I'm far from a purist when it comes to restorations, but I just cant gut a detector unless its a totally corroded/rusted mess. Like to the point where identification of components is impossible coupled with supporting hardware reduced to an oxide. And I do have a couple in that condition....hence the MCA module.

I'm with ya on the restoration price. I've done quite a few (radios included) with most over $300. Shipping can add $60+ to that as well.

Mark Rowley

Re: Cutting edge GM counter (1953)

Posted: Tue Oct 15, 2019 9:20 am
by Roberto Ferrari
Hi Mark

Electronics inside the main box is splitted, as you can see in this picture.
I am not in the mood to track the wires, etc.

Hi Richard
Your approach is great, but I stick to the conservative way, not to modify too much the original object.

Re: Cutting edge GM counter (1953)

Posted: Tue Oct 15, 2019 2:24 pm
by Mark Rowley
Very similar Roberto. High probability the modules are the same.

Mark Rowley

Re: Cutting edge GM counter (1953)

Posted: Tue Oct 15, 2019 5:11 pm
by Roberto Ferrari
Hi Mark

Being similar the models, I accept gladly your offer.
Please get in touch by PM.

Thanks!

Re: Cutting edge GM counter (1953)

Posted: Tue Oct 15, 2019 5:24 pm
by Mark Rowley
-QSL-

Mark Rowley

Re: Cutting edge GM counter (1953)

Posted: Thu Oct 17, 2019 2:15 pm
by Roberto Ferrari
Hi Mark

Thanks a lot for that file.
Very similar design.
Now I will struggle for devoting some time to the restoration.

Re: Cutting edge GM counter (1953)

Posted: Fri Oct 18, 2019 9:50 pm
by Mark Rowley
Just for fun I used a 6.5 decade old PRI 111 Scintillator to detect x-rays coming off the fusor. The 111 goes to full deflection on the 2.5mR scale as I ramp it up from 22 to 25.5kV.

https://www.youtube.com/watch?v=w1cHW6TrhTU

Mark Rowley

Re: Cutting edge GM counter (1953)

Posted: Sat Oct 19, 2019 4:28 am
by Richard Hull
Quite normal near a fusor. I use a victoreen ion chamber detector and, as most here know, my view window points down to the concrete floor. I get about the same reading, (2-3 mr/hr) here when about 12 inches from the fusor body at 38kv. However, if I get the nose pointed in the narrow cone almost touching the window,1-inch away, I get 40mr/hr. At the controller work station, ~ 6 feet, I get about 0.5 mr/hr. from the fusor body and nothing from the cone. My permanently affixed camera, of course, takes the full 40mr/hr and some pixels are lost in the CCD from the 15 years fusor IV has been around.

I have some 100 mren dosimeters and three chargers and always wear one, but to date, they never move off zero as the blast is only present during 3 or 4, 5-minute runs over the two hours it takes to start and take data from the fusor. Based on the .5 mrem/hr ion meter reading with 20 minute total exposure at 6 feet that would register a total dose of 0.5/3 or less than 0.2mrem which is virtually no dose at all.

I took data for over 12 daily runs in a row prior to the HEAS event for a probable total absorbed dose of 12 X 0.2 or 2.4 mrem I rarely run the fusor more than twice yearly. The rest of the time it just collects dust and takes up space.

Put you 111's snout right at the naked window and take a reading and you will see why I point my window straight down into the floor. Will the 111 even read that high??

Richard Hull