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How Do I Make a PCB Shock Resistant?
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 |
How Do I Make a PCB Shock Resistant?
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 |
How Do I Make a PCB Shock Resistant?
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 |
How Do I Make a PCB Shock Resistant?
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." |
How Do I Make a PCB Shock Resistant?
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 |
How Do I Make a PCB Shock Resistant?
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 |
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