File /Doug Moore's Archives/Doug Moore meter puller.docx uploaded
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The following files and folders have been uploaded to
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Description:
Doug Moore's meter puller document
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here is the Doug Moore meter puller document
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? Clint, ? Try using a heat gun or hair dryer on the glue around the base of the meter.? I have disassembled ENI meters using heat.? If you remove the board and leave the meter in the case you can use a flat piece of metal with holes for the meter contact screws and holes for a couple of screws with nuts so you can put some pressure on the back part of the meter to help remove it.? Sometimes the back pressure alone will do it but not always.? I have also used an Xacto knife along the glue joint to help it along.? Somewhere in the files are instructions for making a jig to remove that backs which might give you some ideas. ? Lenox ? ? Subject: Re: [CDV700CLUB] ENI meter source ? George,
I tried the geotropism test by holding the assembled unit upside down, no change. ?Maybe if I open it I can repair it. ?What do you suggest, an X-Acto saw?
Clint
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George,
I tried the geotropism test by holding the assembled unit upside down, no change. ?Maybe if I open it I can repair it. ?What do you suggest, an X-Acto saw?
Clint
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Peter,
It's a little hard to see but it doesn't appear to be hitting the face. ?The needle arc is parallel to the face.
Clint
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Michael,
I tried your suggestions but it still hangs up in the same place.
Clint
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Thank you for the offer, David. ?I found a socket and got it repaired. ?Another good 700 back from the dead.
Clint
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Good on the horseshoe. That's good news. Those are really rugged, sledom have a serious problem compared to the much smaller circular one (no gap).
Also the plastic on the older horseshoe ones is nearly indestructible.
Yoyu can pull the meter off the PCB just by removing the mounting screws, then you can don a thorough visual inspection to see if you can spot any of the issues mentioned by the other members.
A nice simple meter movement tester cana be constructed with a few reistors, one being variable, and a small 1.5V dry cell.
When testing the movement with a tester, the last test is to turn it upside down to see if it behaves the same as in the normal position, called "geotropism test". Back when I was working with CDV-700's on a daily basis I built up a test box that had the movement tester, a very high impedance High Voltage tester, and some switching to connect different pulsers and other test equipment to the CDV-700. The link to some pictures is :??https://www.qsl.net/k0ff/Nuclear_Physics_101_by_George_Dowell/4-DIY%20APPARATUS%20PROJECTS/Apparatus%20We%20Make/Apparatus%20We%20Make/Geiger%20Counter%20Tester/
Geo
----- Original Message ----- From: Clint <clintb@...> To: [email protected]Sent: Wed, 28 Dec 2022 09:41:46 -0500 (EST) Subject: Re: [CDV700CLUB] ENI meter source
I think it's a horseshoe.
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I had an issue with an old Ludlum from 1976 where the magnet metal grains were falling out and caused a mechanical bridge between the magnet and needle coil. I am curious if you can run the black zero adjust "knob" a full 360 degrees and see if the needle moves smoothly or still binds? I also forget if the zero adjustment lets you move the meter full range or not....maybe not.
-Stephen N.
just in case, have you looked athe clearance between the needle and the face of the scale? i've seen bubbled/lifted paint before.?
p
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just in case, have you looked athe clearance between the needle and the face of the scale? i've seen bubbled/lifted paint before.?
p
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Clint -
do you think it could be static charge on the meter face? I had a similar problem with an Eberline RM-15 meter and fixed it by using anti-static solution (DIY).
You could also try a static-cling dryer sheet.
solution I made was
1 TBLS Isopropyl Alcohol (Rubbing Alcohol)
1 drop liquid dish soap
2 oz. Water
re-used eye glass cleaner spray bottle
shake well before each use - mist the meter face and let dry
a very thin soap residue will remain on the meter face - my meter had extreme static and required 3 treatments
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Clint, does that meter have a magnet that is round like a ci8rcle, not horseshoe shaped?
If so, those are pressed ceramic not iron, and are notorious for shedding flakes of its material, which clogs up the channel where the coil moves.
Doug Moore came up with a clever clamp that allows the meter to be taken aopart, and if careful and lucky, those can be saved.
Geo
----- Original Message ----- From: Clint <clintb@...> To: [email protected]Sent: Tue, 27 Dec 2022 14:29:34 -0500 (EST) Subject: [CDV700CLUB] ENI meter source
Hello,
I just got another shiny new, clean ENI 700 in mint condition and while the circuit seems to be working the meter stops around 200 CPM as if it is hitting something. ?I know the high-range meter with the R/hr scale is the OCD-M-151. ?Is there a similar OCD number for the ENI meter? ?The book says it's a Weston 100201-M. ?Since the ENI attaches directly to the circuit board the spacing between the posts is critical. ?Substituting a Victoreen meter will not work.
I've had no luck searching the Weston part number. Does anyone know the OCD number?
Thanks,
Clint
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Hello,
I just got another shiny new, clean ENI 700 in mint condition and while the circuit seems to be working the meter stops around 200 CPM as if it is hitting something. ?I know the high-range meter with the R/hr scale is the OCD-M-151. ?Is there a similar OCD number for the ENI meter? ?The book says it's a Weston 100201-M. ?Since the ENI attaches directly to the circuit board the spacing between the posts is critical. ?Substituting a Victoreen meter will not work.
I've had no luck searching the Weston part number. Does anyone know the OCD number?
Thanks,
Clint
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Re: Newbie at this, how do you calibrate the CD V700?
Best wishes for you and yours too dear Pavlos.
George
----- Original Message ----- From: Pavlos H via groups.io <pchoust@...> To: [email protected]Sent: Tue, 27 Dec 2022 05:44:44 -0500 (EST) Subject: Re: [CDV700CLUB] Newbie at this, how do you calibrate the CD V700?
Happy Holidays George!
Very interesting and illuminating!
Pavlos
On Monday, December 26, 2022 at 05:02:29 PM GMT+2, Geo Dowell <geoelectronics@...> wrote:
All good questions Jason.?
All: Please refer to individual detailed papers on this subject and many more here:
https://www.qsl.net/k0ff/Nuclear_Physics_101_by_George_Dowell/
Happy Hobbydays!
Geo
----- Original Message ----- From: Jason B <sydbowen@...> To: [email protected]Sent: Mon, 26 Dec 2022 01:43:49 -0500 (EST) Subject: Re: [CDV700CLUB] Newbie at this, how do you calibrate the CD V700?
Thanks for the replies. From my slim understanding of what I'm dealing with and what I'm reading here, the pulser is the only correct way to calibrate for counts per minute. Now if a person were to calibrate with a radioactive source would they go by the mR/hr scale? Seems like that could be an issue if you calibrate with one element and are reading a different radioactive element. CPM is CPM regardless of what beta emitter you're dealing with but mR/hr is tied to the energy of the particles right??
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Re: Newbie at this, how do you calibrate the CD V700?
Happy Holidays George!
Very interesting and illuminating!
Pavlos
On Monday, December 26, 2022 at 05:02:29 PM GMT+2, Geo Dowell <geoelectronics@...> wrote:
All good questions Jason.?
All: Please refer to individual detailed papers on this subject and many more here:
https://www.qsl.net/k0ff/Nuclear_Physics_101_by_George_Dowell/
Happy Hobbydays!
Geo
----- Original Message ----- From: Jason B <sydbowen@...> To: [email protected]Sent: Mon, 26 Dec 2022 01:43:49 -0500 (EST) Subject: Re: [CDV700CLUB] Newbie at this, how do you calibrate the CD V700?
Thanks for the replies. From my slim understanding of what I'm dealing with and what I'm reading here, the pulser is the only correct way to calibrate for counts per minute. Now if a person were to calibrate with a radioactive source would they go by the mR/hr scale? Seems like that could be an issue if you calibrate with one element and are reading a different radioactive element. CPM is CPM regardless of what beta emitter you're dealing with but mR/hr is tied to the energy of the particles right??
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Re: Probe voltage and calibration.
Voltage does affect the response unless you are on the plateau.
That response curve should be published somewhere or when you buy
a tube. Stay within the plateau and you are fine. Less voltage is
better for the sake of the other components, so you are doing it
right.
On 12/26/2022 8:26 AM, Clint wrote:
toggle quoted message
Show quoted text
All,
Does the voltage applied to the geiger tube have a significant
effect on the calibration if it is within the operating range or
'plateau'?
For the LND720, if I were to correct 950V down to 900V is
recalibration required?
Clint
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Re: Newbie at this, how do you calibrate the CD V700?
The 6993 tube is energy compensated for gamma, but counts are
counts.
On 12/26/2022 1:43 AM, Jason B wrote:
toggle quoted message
Show quoted text
Thanks for the replies. From my slim understanding of what I'm
dealing with and what I'm reading here, the pulser is the only
correct way to calibrate for counts per minute. Now if a person
were to calibrate with a radioactive source would they go by the
mR/hr scale? Seems like that could be an issue if you calibrate
with one element and are reading a different radioactive element.
CPM is CPM regardless of what beta emitter you're dealing with but
mR/hr is tied to the energy of the particles right??
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Re: Probe voltage and calibration.
This is great, real world data Mike, thank you. ?
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Re: Probe voltage and calibration.
Clint,
This gives me an excuse to play with my new (to me) Bicron frisk-tech scaler!? It has about a 300 mV threshold.? The source used was a Fiestaware bowl with the pickle probe clamped in a static position in the bowl.? One minute count totals follow.? I would describe the difference as too small to worry about (4%), although it is statistically significant.
900V:? ?
2662
2566
2625
950V:
2745
2661
2784
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David71
Mike L.