Good morning, all. I'm brand new to hands-on electronic repair so please pardon any silly questions.

I recently acquired a Geiger counter manufactured in 1962 and I am rebuilding it. The PCB is 4" x 4" and 0.062" thick. The part of the chassis to which it mounts has four steel legs that protrude 1.45" perpendicular to the plane of the chassis. The four corners of the PCB screw onto these steel legs..

I would like to know some options for making the PCB more shock resistant should the unit ever get dropped. Is there any such thing as, say, shock-resistant washers that could go over the four screws and sit between the PCB and the steel legs to which it's mounted? Or is there a better way?

Any suggestions geared towards a newbie would be greatly appreciated. Thanks, all!

Kindly,

Matthew Connor

On Wed, 17 Jun 2015 05:37:33 -0700 (PDT), Matthew Connor
wrote:

Good morning, all. I'm brand new to hands-on electronic repair so please pardon any silly questions.

I recently acquired a Geiger counter manufactured in 1962 and I am rebuilding it. The PCB is 4" x 4" and 0.062" thick. The part of the chassis to which it mounts has four steel legs that protrude 1.45" perpendicular to the plane of the chassis. The four corners of the PCB screw onto these steel legs.

I would like to know some options for making the PCB more shock resistant should the unit ever get dropped. Is there any such thing as, say, shock-resistant washers that could go over the four screws and sit between the PCB and the steel legs to which it's mounted? Or is there a better way?

1962 might be a CD-V700M counter. It matches your description:
https://www.google.com/search?tbm=isch&q=cd-v700m
I have one of those. How am I doing. Is there a reason why you
failed to disclose the model number?

Maybe small rubber grommets in the holes in the PCB. Something like
these:
http://www.customgasketmfg.com/Images/Rubber-Grommets-Bushings.jpg
If you can't find ones that fit, or you don't want to enlarge the
holes, use two rubber flat washers instead. You can get those in the
plumbing section at the hardware store. You may need to install metal
washer(s) on the grommet to secure the head. You can get fancy by
adding a coil spring under the screw head.

The problem with such simplistic schemes is that adding a washer
between the bracket and the PCB is going to raise the PCB by the
thickness of the washer. That means that front panel switches and
lights might not fit. If there is the usual big rotary switch in the
middle of the front panel, it too will need to be shock mounted,
probably with another grommet around the shaft.

Personally, I think you should make these modifications unless you
have a good reason to need additional shock resistance. Such
mechanical things really should be done with the initial design, not
as a retrofit. In 1962, phenolic (paper) PCB's were fashionable,
which might crumble if you try to "modify" them. I suspect you might
do more damage than good. However, if you MUST make it more shock
resistant, such as for transportation in a vehicle without shock
absorbers over a rotten road, some kind of foam lined packing case
would probably be helpful.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Wed, 17 Jun 2015 05:37:33 -0700 (PDT), Matthew Connor
wrote:

Good morning, all. I'm brand new to hands-on electronic repair so please pardon any silly questions.

I recently acquired a Geiger counter manufactured in 1962 and I am rebuilding it. The PCB is 4" x 4" and 0.062" thick. The part of the chassis to which it mounts has four steel legs that protrude 1.45" perpendicular to the plane of the chassis. The four corners of the PCB screw onto these steel legs.

I would like to know some options for making the PCB more shock resistant should the unit ever get dropped. Is there any such thing as, say, shock-resistant washers that could go over the four screws and sit between the PCB and the steel legs to which it's mounted? Or is there a better way?

Any suggestions geared towards a newbie would be greatly appreciated. Thanks, all!

Kindly,

Matthew Connor
If the PCB was free from damage caused by shock when you got it then I
would suggest that it was probably built robuslty enough already
considering that it has survived for 53 years. Certainly if you are
exposed to radiation strong enough to cause you to drop the thing you
won't be living long enough to care if it broke when dropped. What
radiation source are you going to use to test it? Many if not most
smoke detectors have a little Americium that irradiates the air in a
little chamber. Removing the cover allows this radiation to, well,
radiate into the local environment and is a pretty good source to see
if your counter works at all. Another common source for radiation are
the 2% thoriated tungstenTIG welding electrodes. They will not make
your counter click as often as the smoke detector source though. The
mantles for Coleman type lanterns also used to have thoria in them
though I think another rare earth is now being used. Once you know
your counter is working it is fun to see what else in your environment
is more radioactive than the general background radiation. Certain
rocks may be more radioactive as well as concrete. Some green
glassware and some glazes on ceramics are radioactive.
Eric

On 06/17/2015 5:37 AM, Matthew Connor wrote:
Good morning, all. I'm brand new to hands-on electronic repair so please pardon any silly questions.

I recently acquired a Geiger counter manufactured in 1962 and I am rebuilding it. The PCB is 4" x 4" and 0.062" thick. The part of the chassis to which it mounts has four steel legs that protrude 1.45" perpendicular to the plane of the chassis. The four corners of the PCB screw onto these steel legs..

I would like to know some options for making the PCB more shock resistant should the unit ever get dropped. Is there any such thing as, say, shock-resistant washers that could go over the four screws and sit between the PCB and the steel legs to which it's mounted? Or is there a better way?

Any suggestions geared towards a newbie would be greatly appreciated. Thanks, all!

Kindly,

Matthew Connor


You can always encapsulate it in two part epoxy. MG Chemicals (and
others) sell these kits.

Mind you you won't be able to easily remove the encapsulation later
unless you soak the blob in acetone for a day or two to soften the epoxy...

John :-#)#

--
(Please post followups or tech inquiries to the USENET newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
(604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."

On Thursday, 18 June 2015 11:57:54 UTC-4, wrote:
On Wed, 17 Jun 2015 05:37:33 -0700 (PDT), Matthew Connor
wrote:

Good morning, all. I'm brand new to hands-on electronic repair so please pardon any silly questions.

I recently acquired a Geiger counter manufactured in 1962 and I am rebuilding it. The PCB is 4" x 4" and 0.062" thick. The part of the chassis to which it mounts has four steel legs that protrude 1.45" perpendicular to the plane of the chassis. The four corners of the PCB screw onto these steel legs.

I would like to know some options for making the PCB more shock resistant should the unit ever get dropped. Is there any such thing as, say, shock-resistant washers that could go over the four screws and sit between the PCB and the steel legs to which it's mounted? Or is there a better way?

Any suggestions geared towards a newbie would be greatly appreciated. Thanks, all!

Kindly,

Matthew Connor
If the PCB was free from damage caused by shock when you got it then I
would suggest that it was probably built robuslty enough already
considering that it has survived for 53 years. Certainly if you are
exposed to radiation strong enough to cause you to drop the thing you
won't be living long enough to care if it broke when dropped. What
radiation source are you going to use to test it? Many if not most
smoke detectors have a little Americium that irradiates the air in a
little chamber. Removing the cover allows this radiation to, well,
radiate into the local environment and is a pretty good source to see
if your counter works at all. Another common source for radiation are
the 2% thoriated tungstenTIG welding electrodes. They will not make
your counter click as often as the smoke detector source though. The
mantles for Coleman type lanterns also used to have thoria in them
though I think another rare earth is now being used. Once you know
your counter is working it is fun to see what else in your environment
is more radioactive than the general background radiation. Certain
rocks may be more radioactive as well as concrete. Some green
glassware and some glazes on ceramics are radioactive.
Eric

Eric, thanks so much for your input! Based on your response and on Jeff's, it's obvious I should have included more detail. My apologies! This is a Lionel CD V-700 Model 6b manufactured in 1962. I do not know what type of material the PCB is made from for certain but I'd like to find out. If I included a picture, would that help?

As for its condition when I received it, it was in bad enough shape (PCB-wise) that I had to rebuild it. Many of the wires had all but one or two strands broken loose from their respective solder joints so relatively speaking, a lot of electricity was going through very little conductor. Because of the way those and some other components broken, I am suspecting shock as the primary cause, thus leading me to ask about this modification. I will certainly take your thoughts into account. I'm very grateful. Thanks again! -Matthew

On Wednesday, 17 June 2015 13:10:06 UTC-4, Jeff Liebermann wrote:
On Wed, 17 Jun 2015 05:37:33 -0700 (PDT), Matthew Connor
wrote:

Good morning, all. I'm brand new to hands-on electronic repair so please pardon any silly questions.

I recently acquired a Geiger counter manufactured in 1962 and I am rebuilding it. The PCB is 4" x 4" and 0.062" thick. The part of the chassis to which it mounts has four steel legs that protrude 1.45" perpendicular to the plane of the chassis. The four corners of the PCB screw onto these steel legs.

I would like to know some options for making the PCB more shock resistant should the unit ever get dropped. Is there any such thing as, say, shock-resistant washers that could go over the four screws and sit between the PCB and the steel legs to which it's mounted? Or is there a better way?

1962 might be a CD-V700M counter. It matches your description:
https://www.google.com/search?tbm=isch&q=cd-v700m
I have one of those. How am I doing. Is there a reason why you
failed to disclose the model number?

Maybe small rubber grommets in the holes in the PCB. Something like
these:
http://www.customgasketmfg.com/Images/Rubber-Grommets-Bushings.jpg
If you can't find ones that fit, or you don't want to enlarge the
holes, use two rubber flat washers instead. You can get those in the
plumbing section at the hardware store. You may need to install metal
washer(s) on the grommet to secure the head. You can get fancy by
adding a coil spring under the screw head.

The problem with such simplistic schemes is that adding a washer
between the bracket and the PCB is going to raise the PCB by the
thickness of the washer. That means that front panel switches and
lights might not fit. If there is the usual big rotary switch in the
middle of the front panel, it too will need to be shock mounted,
probably with another grommet around the shaft.

Personally, I think you should make these modifications unless you
have a good reason to need additional shock resistance. Such
mechanical things really should be done with the initial design, not
as a retrofit. In 1962, phenolic (paper) PCB's were fashionable,
which might crumble if you try to "modify" them. I suspect you might
do more damage than good. However, if you MUST make it more shock
resistant, such as for transportation in a vehicle without shock
absorbers over a rotten road, some kind of foam lined packing case
would probably be helpful.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Hi, Jeff! Sorry for the lack of details. This is a Lionel CD V-700 Model 6b manufactured in 1962. I like the grommet idea very much...thanks! -Matthew

On Thu, 18 Jun 2015 09:03:19 -0700, wrote:

On Wed, 17 Jun 2015 05:37:33 -0700 (PDT), Matthew Connor
wrote:

Good morning, all. I'm brand new to hands-on electronic repair so please pardon any silly questions.

I recently acquired a Geiger counter manufactured in 1962 and I am rebuilding it. The PCB is 4" x 4" and 0.062" thick. The part of the chassis to which it mounts has four steel legs that protrude 1.45" perpendicular to the plane of the chassis. The four corners of the PCB screw onto these steel legs.

I would like to know some options for making the PCB more shock resistant should the unit ever get dropped. Is there any such thing as, say, shock-resistant washers that could go over the four screws and sit between the PCB and the steel legs to which it's mounted? Or is there a better way?

Any suggestions geared towards a newbie would be greatly appreciated. Thanks, all!

Kindly,

Matthew Connor
If the PCB was free from damage caused by shock when you got it then I
would suggest that it was probably built robuslty enough already
considering that it has survived for 53 years. Certainly if you are
exposed to radiation strong enough to cause you to drop the thing you
won't be living long enough to care if it broke when dropped. What
radiation source are you going to use to test it? Many if not most
smoke detectors have a little Americium that irradiates the air in a
little chamber. Removing the cover allows this radiation to, well,
radiate into the local environment and is a pretty good source to see
if your counter works at all. Another common source for radiation are
the 2% thoriated tungstenTIG welding electrodes. They will not make
your counter click as often as the smoke detector source though. The
mantles for Coleman type lanterns also used to have thoria in them
though I think another rare earth is now being used. Once you know
your counter is working it is fun to see what else in your environment
is more radioactive than the general background radiation. Certain
rocks may be more radioactive as well as concrete. Some green
glassware and some glazes on ceramics are radioactive.
Eric


If you happen to have any Pentax or Carl Zeiss Jena lens from the 60s
that have turned yellow, they are a good radiation source for testing
a Geiger counter.

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