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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
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Newbie Question: Filing Down Component Leads
Good morning, all! While technically minded, I am brand new to repairing PCBs. I'd therefore greatly appreciate relatively simple explanations and your indulgence of my ignorance.
I recently obtained a Geiger counter which was in need of being rebuilt. Because it was manufactured in 1962, the components are large and provide me with plenty of working room. After desoldering all components, I took a locksmith's file (very small and fine) and took off just the immediate outer layer of the leads of the components. My intention was to remove existing solder and any other "gunk". As soon as I began to see the copper color of the lead showing through, I stopped and moved on to the next. After doing this for all components, I soldered them back in and everything is working perfectly...for now. I ran across some information AFTER doing this that tells me that might have been a bad idea. Are component leads coated with something protective that I should have left on? Should I expect earlier-than-usual failure from any of my components since I filed off this outer layer? Any insight is much appreciated. Thanks a ton! Kindly, Matthew Connor |
#2
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Newbie Question: Filing Down Component Leads
"Matthew Connor" wrote in message ... Good morning, all! While technically minded, I am brand new to repairing PCBs. I'd therefore greatly appreciate relatively simple explanations and your indulgence of my ignorance. I recently obtained a Geiger counter which was in need of being rebuilt. Because it was manufactured in 1962, the components are large and provide me with plenty of working room. After desoldering all components, I took a locksmith's file (very small and fine) and took off just the immediate outer layer of the leads of the components. My intention was to remove existing solder and any other "gunk". As soon as I began to see the copper color of the lead showing through, I stopped and moved on to the next. After doing this for all .components, I soldered them back in and everything is working perfectly...for now. I ran across some information AFTER doing this that tells me that might have been a bad idea. Are .component leads coated with something protective that I should have left on? Should I expect earlier-than-usual failure from any of my components since I filed off this outer layer? Any insight is much appreciated. Most component leads are tinned. That is the copper wire is coated with a thin layer of solder. This makes it easier for soldering. Copper will oxidise very fast, so don't scrape the tinned wires to bare copper. It will not hirt anything,but just make soldering more difficult. When repairing circuits use some 60/40 solder with rosin core flux. That is unless you run across some of the newer lead free stuff. You might alos want to get a bottle of the liquid flux to use. Just make sure the flux is for electronic work. There is some acid flux that is made mainly for plumming. It will tend to draw moisture out of the air and corrode the copper in electronics. If you think there is a lot of crud on the wires, use one of the Scotch Bright typw pads to just shine them up, but not enought to remove the old solder. It is often recommended to tin the bare copper wires before soldering them. I doubt you will get any failure because you scraped off the coating. |
#3
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Newbie Question: Filing Down Component Leads
On 06/17/2015 10:20 AM, Ralph Mowery wrote:
"Matthew Connor" wrote in message ... Good morning, all! While technically minded, I am brand new to repairing PCBs. I'd therefore greatly appreciate relatively simple explanations and your indulgence of my ignorance. I recently obtained a Geiger counter which was in need of being rebuilt. Because it was manufactured in 1962, the components are large and provide me with plenty of working room. After desoldering all components, I took a locksmith's file (very small and fine) and took off just the immediate outer layer of the leads of the components. My intention was to remove existing solder and any other "gunk". As soon as I began to see the copper color of the lead showing through, I stopped and moved on to the next. After doing this for all .components, I soldered them back in and everything is working perfectly...for now. I ran across some information AFTER doing this that tells me that might have been a bad idea. Are .component leads coated with something protective that I should have left on? Should I expect earlier-than-usual failure from any of my components since I filed off this outer layer? Any insight is much appreciated. Most component leads are tinned. That is the copper wire is coated with a thin layer of solder. This makes it easier for soldering. Copper will oxidise very fast, so don't scrape the tinned wires to bare copper. It will not hirt anything,but just make soldering more difficult. When repairing circuits use some 60/40 solder with rosin core flux. That is unless you run across some of the newer lead free stuff. You might alos want to get a bottle of the liquid flux to use. Just make sure the flux is for electronic work. There is some acid flux that is made mainly for plumming. It will tend to draw moisture out of the air and corrode the copper in electronics. If you think there is a lot of crud on the wires, use one of the Scotch Bright typw pads to just shine them up, but not enought to remove the old solder. It is often recommended to tin the bare copper wires before soldering them. I doubt you will get any failure because you scraped off the coating. You can get RA flux (rosin, activated) in solder or in a bottle. It cleans off oxidized leads very well. Kester 44 solder is RA, and you can get the same stuff as Kester 1544 (only in gallons or pails unfortunately). However, MG Chemicals 835 RA flux is available from Digikey or Amazon in much smaller quantities for about 10 bucks. I use a small bottle with a stainless steel needle. When the needle clogs up (as it will), just touch it with the iron and it magically clears out. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net |
#4
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Newbie Question: Filing Down Component Leads
On Wednesday, June 17, 2015 at 8:09:27 AM UTC-4, Matthew Connor wrote:
Good morning, all! While technically minded, I am brand new to repairing PCBs. I'd therefore greatly appreciate relatively simple explanations and your indulgence of my ignorance. I recently obtained a Geiger counter which was in need of being rebuilt. Because it was manufactured in 1962, the components are large and provide me with plenty of working room. After desoldering all components, I took a locksmith's file (very small and fine) and took off just the immediate outer layer of the leads of the components. My intention was to remove existing solder and any other "gunk". As soon as I began to see the copper color of the lead showing through, I stopped and moved on to the next. After doing this for all components, I soldered them back in and everything is working perfectly...for now. I ran across some information AFTER doing this that tells me that might have been a bad idea. Are component leads coated with something protective that I should have left on? Should I expect earlier-than-usual failure from any of my components since I filed off this outer layer? Any insight is much appreciated. Thanks a ton! Kindly, Matthew Connor A lot of work for probably no real reason. If the solder wetted properly on the leads, then no further action is required. Occasionally you'll run into a component lead that defies soldering. Normally, cranking the heat on the soldering station and adding some flux will crack the oxidation and the solder will flow out. |
#5
Posted to sci.electronics.repair
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Newbie Question: Filing Down Component Leads
On Wed, 17 Jun 2015 05:09:24 -0700 (PDT), Matthew Connor
wrote: I am brand new to repairing PCBs. I'd therefore greatly appreciate relatively simple explanations and your indulgence of my ignorance. This is Usenet. There are no simple explanations. I recently obtained a Geiger counter which was in need of being rebuilt. Because it was manufactured in 1962, the components are large and provide me with plenty of working room. Rebuilt? Mechanically, electronically, or both? Maker and model number? For 1962, my guess(tm) would be a bright yellow Lionel CD-V700m. https://www.google.com/search?tbm=isch&q=cd-v700m You might also want to look into modifications: http://home.comcast.net/~prutchi/index_files/cdv700pro.htm After desoldering all components, If it's what I think it is, the PCB is made from phenolic (paper). Phenolic boards do NOT tolerate much heat, soldering, bending, etc. In other words, the traces fall off and the board delaminates or crumbles. Your desoldering may have trashed the PCB. I took a locksmith's file (very small and fine) and took off just the immediate outer layer of the leads of the components. Some counters were coated with some kind of conformal coating in order to protect the high voltage that runs the GM tube. You should not have removed it and will probably need to reapply it to the high voltage components and PCB. Phenolic is hygroscopic (absorbs moisture) and will need to be heated for a while to evaporate moisture before it can be coated. Personally, I think you just ruined it. It might be easier to just make a replacement G10/FR4 PCB. You can also add your additional shock mounting more easily. There may also be a market for your unused boards. Check the Yahoo Geiger Counter groups (there are several) for advice on this: https://groups.yahoo.com/neo/groups/GeigerCounterEnthusiasts/info My intention was to remove existing solder and any other "gunk". The best of intentions will probably lead to a trashed counter. I suggest that you stop and thing this over before blundering forward. As soon as I began to see the copper color of the lead showing through, I stopped and moved on to the next. After doing this for all components, I soldered them back in and everything is working perfectly...for now. Open the counter and just breath onto the PCB. That puts a thin layer of moisture on everything. If it continues to operate normally, you win. If it craps out and recovers when the moisture evaporates, you'll need to deal with replacing the coating that you removed. I ran across some information AFTER doing this that tells me that might have been a bad idea. We seem to do things in much the same way. I always read the instructions after I get into trouble. It's more fun that way, but does have the disadvantage of destroying things if I miss something. Are component leads coated with something protective that I should have left on? Tinning, which prevent the underlying copper from oxidizing and turning into green crud. Also, the conformal coating to prevent condensation from shorting out the hi-v section. Should I expect earlier-than-usual failure from any of my components since I filed off this outer layer? Any insight is much appreciated. No. They're fine. After all, the counter was probably designed to survive a nuclear attack. Good luck. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#6
Posted to sci.electronics.repair
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Newbie Question: Filing Down Component Leads
On Wednesday, June 17, 2015 at 11:58:03 AM UTC-4, Phil Hobbs wrote:
On 06/17/2015 10:20 AM, Ralph Mowery wrote: "Matthew Connor" wrote in message ... Good morning, all! While technically minded, I am brand new to repairing PCBs. I'd therefore greatly appreciate relatively simple explanations and your indulgence of my ignorance. I recently obtained a Geiger counter which was in need of being rebuilt. Because it was manufactured in 1962, the components are large and provide me with plenty of working room. After desoldering all components, I took a locksmith's file (very small and fine) and took off just the immediate outer layer of the leads of the components. My intention was to remove existing solder and any other "gunk". As soon as I began to see the copper color of the lead showing through, I stopped and moved on to the next. After doing this for all .components, I soldered them back in and everything is working perfectly...for now. I ran across some information AFTER doing this that tells me that might have been a bad idea. Are .component leads coated with something protective that I should have left on? Should I expect earlier-than-usual failure from any of my components since I filed off this outer layer? Any insight is much appreciated. Most component leads are tinned. That is the copper wire is coated with a thin layer of solder. This makes it easier for soldering. Copper will oxidise very fast, so don't scrape the tinned wires to bare copper. It will not hirt anything,but just make soldering more difficult. When repairing circuits use some 60/40 solder with rosin core flux. That is unless you run across some of the newer lead free stuff. You might alos want to get a bottle of the liquid flux to use. Just make sure the flux is for electronic work. There is some acid flux that is made mainly for plumming. It will tend to draw moisture out of the air and corrode the copper in electronics. If you think there is a lot of crud on the wires, use one of the Scotch Bright typw pads to just shine them up, but not enought to remove the old solder. It is often recommended to tin the bare copper wires before soldering them. I doubt you will get any failure because you scraped off the coating. You can get RA flux (rosin, activated) in solder or in a bottle. It cleans off oxidized leads very well. Kester 44 solder is RA, and you can get the same stuff as Kester 1544 (only in gallons or pails unfortunately). However, MG Chemicals 835 RA flux is available from Digikey or Amazon in much smaller quantities for about 10 bucks. I use a small bottle with a stainless steel needle. When the needle clogs up (as it will), just touch it with the iron and it magically clears out. I've had old copper wires (In some old insulation.. zip cord type stuff) and it gets and oxide/ coating/ something/ that flux doesn't attack very well. I end up having to first scrap it with sand paper or a green scrubbie. (Scotch brite) and then tin it. I've always wondered what the tenacious oxide is. George H. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net |
#8
Posted to sci.electronics.repair
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Newbie Question: Filing Down Component Leads
On Wednesday, 17 June 2015 13:30:40 UTC-4, Jeff Liebermann wrote:
On Wed, 17 Jun 2015 05:09:24 -0700 (PDT), Matthew Connor Matthew wrote: I am brand new to repairing PCBs. I'd therefore greatly appreciate relatively simple explanations and your indulgence of my ignorance. This is Usenet. There are no simple explanations. I recently obtained a Geiger counter which was in need of being rebuilt. Because it was manufactured in 1962, the components are large and provide me with plenty of working room. Rebuilt? Mechanically, electronically, or both? Maker and model number? For 1962, my guess(tm) would be a bright yellow Lionel CD-V700m. https://www.google.com/search?tbm=isch&q=cd-v700m You might also want to look into modifications: http://home.comcast.net/~prutchi/index_files/cdv700pro.htm After desoldering all components, If it's what I think it is, the PCB is made from phenolic (paper). Phenolic boards do NOT tolerate much heat, soldering, bending, etc. In other words, the traces fall off and the board delaminates or crumbles. Your desoldering may have trashed the PCB. I took a locksmith's file (very small and fine) and took off just the immediate outer layer of the leads of the components. Some counters were coated with some kind of conformal coating in order to protect the high voltage that runs the GM tube. You should not have removed it and will probably need to reapply it to the high voltage components and PCB. Phenolic is hygroscopic (absorbs moisture) and will need to be heated for a while to evaporate moisture before it can be coated. Personally, I think you just ruined it. It might be easier to just make a replacement G10/FR4 PCB. You can also add your additional shock mounting more easily. There may also be a market for your unused boards. Check the Yahoo Geiger Counter groups (there are several) for advice on this: https://groups.yahoo.com/neo/groups/GeigerCounterEnthusiasts/info My intention was to remove existing solder and any other "gunk". The best of intentions will probably lead to a trashed counter. I suggest that you stop and thing this over before blundering forward. As soon as I began to see the copper color of the lead showing through, I stopped and moved on to the next. After doing this for all components, I soldered them back in and everything is working perfectly...for now. Open the counter and just breath onto the PCB. That puts a thin layer of moisture on everything. If it continues to operate normally, you win. If it craps out and recovers when the moisture evaporates, you'll need to deal with replacing the coating that you removed. I ran across some information AFTER doing this that tells me that might have been a bad idea. We seem to do things in much the same way. I always read the instructions after I get into trouble. It's more fun that way, but does have the disadvantage of destroying things if I miss something. Are component leads coated with something protective that I should have left on? Tinning, which prevent the underlying copper from oxidizing and turning into green crud. Also, the conformal coating to prevent condensation from shorting out the hi-v section. Should I expect earlier-than-usual failure from any of my components since I filed off this outer layer? Any insight is much appreciated. No. They're fine. After all, the counter was probably designed to survive a nuclear attack. Good luck. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 Good morning, Jeff! Thank you so much for your insight. My counter is a Lionel CD V-700 Model 6b, manufacture date 1962. On one hand, I'm a little confused. You mentioned several times different variations of me having likely "trashed" my counter by doing what I did. At the very end however, when I asked if I had done any harm, you said, "No. They're fine. After all, the counter was probably designed to survive a nuclear attack." So I'm not quite sure that I'm understanding if what I did was bad or not. On the other hand, you have given me lots of details to consider and suggestions in areas I haven't even started to think about. You've obviously got a great deal of experience and I'll be taking all of your suggestions into account as I move forward with my project. I'll be trying the breath moisture thing right away. Thanks for taking the time to educate an east coast newbie! -Matthew |
#9
Posted to sci.electronics.repair
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Newbie Question: Filing Down Component Leads
On Wednesday, 17 June 2015 11:58:03 UTC-4, Phil Hobbs wrote:
On 06/17/2015 10:20 AM, Ralph Mowery wrote: "Matthew Connor" wrote in message ... Good morning, all! While technically minded, I am brand new to repairing PCBs. I'd therefore greatly appreciate relatively simple explanations and your indulgence of my ignorance. I recently obtained a Geiger counter which was in need of being rebuilt. Because it was manufactured in 1962, the components are large and provide me with plenty of working room. After desoldering all components, I took a locksmith's file (very small and fine) and took off just the immediate outer layer of the leads of the components. My intention was to remove existing solder and any other "gunk". As soon as I began to see the copper color of the lead showing through, I stopped and moved on to the next. After doing this for all .components, I soldered them back in and everything is working perfectly...for now. I ran across some information AFTER doing this that tells me that might have been a bad idea. Are .component leads coated with something protective that I should have left on? Should I expect earlier-than-usual failure from any of my components since I filed off this outer layer? Any insight is much appreciated. Most component leads are tinned. That is the copper wire is coated with a thin layer of solder. This makes it easier for soldering. Copper will oxidise very fast, so don't scrape the tinned wires to bare copper. It will not hirt anything,but just make soldering more difficult. When repairing circuits use some 60/40 solder with rosin core flux. That is unless you run across some of the newer lead free stuff. You might alos want to get a bottle of the liquid flux to use. Just make sure the flux is for electronic work. There is some acid flux that is made mainly for plumming. It will tend to draw moisture out of the air and corrode the copper in electronics. If you think there is a lot of crud on the wires, use one of the Scotch Bright typw pads to just shine them up, but not enought to remove the old solder. It is often recommended to tin the bare copper wires before soldering them. I doubt you will get any failure because you scraped off the coating. You can get RA flux (rosin, activated) in solder or in a bottle. It cleans off oxidized leads very well. Kester 44 solder is RA, and you can get the same stuff as Kester 1544 (only in gallons or pails unfortunately). However, MG Chemicals 835 RA flux is available from Digikey or Amazon in much smaller quantities for about 10 bucks. I use a small bottle with a stainless steel needle. When the needle clogs up (as it will), just touch it with the iron and it magically clears out. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net Dr. Hobbs: Thank you very much for your insight, sir! It's greatly appreciated! -Matthew |
#10
Posted to sci.electronics.repair
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Newbie Question: Filing Down Component Leads
On Wednesday, 17 June 2015 10:20:53 UTC-4, Ralph Mowery wrote:
"Matthew Connor" wrote in message ... Good morning, all! While technically minded, I am brand new to repairing PCBs. I'd therefore greatly appreciate relatively simple explanations and your indulgence of my ignorance. I recently obtained a Geiger counter which was in need of being rebuilt. Because it was manufactured in 1962, the components are large and provide me with plenty of working room. After desoldering all components, I took a locksmith's file (very small and fine) and took off just the immediate outer layer of the leads of the components. My intention was to remove existing solder and any other "gunk". As soon as I began to see the copper color of the lead showing through, I stopped and moved on to the next. After doing this for all .components, I soldered them back in and everything is working perfectly...for now. I ran across some information AFTER doing this that tells me that might have been a bad idea. Are .component leads coated with something protective that I should have left on? Should I expect earlier-than-usual failure from any of my components since I filed off this outer layer? Any insight is much appreciated. Most component leads are tinned. That is the copper wire is coated with a thin layer of solder. This makes it easier for soldering. Copper will oxidise very fast, so don't scrape the tinned wires to bare copper. It will not hirt anything,but just make soldering more difficult. When repairing circuits use some 60/40 solder with rosin core flux. That is unless you run across some of the newer lead free stuff. You might alos want to get a bottle of the liquid flux to use. Just make sure the flux is for electronic work. There is some acid flux that is made mainly for plumming. It will tend to draw moisture out of the air and corrode the copper in electronics. If you think there is a lot of crud on the wires, use one of the Scotch Bright typw pads to just shine them up, but not enought to remove the old solder. It is often recommended to tin the bare copper wires before soldering them. I doubt you will get any failure because you scraped off the coating. Ralph, good morning! Thanks a ton for your input! I'm appreciative! -Matthew |
#11
Posted to sci.electronics.repair
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Newbie Question: Filing Down Component Leads
On 06/19/2015 08:47 AM, Matthew Connor wrote:
On Wednesday, 17 June 2015 11:58:03 UTC-4, Phil Hobbs wrote: On 06/17/2015 10:20 AM, Ralph Mowery wrote: "Matthew Connor" wrote in message ... Good morning, all! While technically minded, I am brand new to repairing PCBs. I'd therefore greatly appreciate relatively simple explanations and your indulgence of my ignorance. I recently obtained a Geiger counter which was in need of being rebuilt. Because it was manufactured in 1962, the components are large and provide me with plenty of working room. After desoldering all components, I took a locksmith's file (very small and fine) and took off just the immediate outer layer of the leads of the components. My intention was to remove existing solder and any other "gunk". As soon as I began to see the copper color of the lead showing through, I stopped and moved on to the next. After doing this for all .components, I soldered them back in and everything is working perfectly...for now. I ran across some information AFTER doing this that tells me that might have been a bad idea. Are .component leads coated with something protective that I should have left on? Should I expect earlier-than-usual failure from any of my components since I filed off this outer layer? Any insight is much appreciated. Most component leads are tinned. That is the copper wire is coated with a thin layer of solder. This makes it easier for soldering. Copper will oxidise very fast, so don't scrape the tinned wires to bare copper. It will not hirt anything,but just make soldering more difficult. When repairing circuits use some 60/40 solder with rosin core flux. That is unless you run across some of the newer lead free stuff. You might alos want to get a bottle of the liquid flux to use. Just make sure the flux is for electronic work. There is some acid flux that is made mainly for plumming. It will tend to draw moisture out of the air and corrode the copper in electronics. If you think there is a lot of crud on the wires, use one of the Scotch Bright typw pads to just shine them up, but not enought to remove the old solder. It is often recommended to tin the bare copper wires before soldering them. I doubt you will get any failure because you scraped off the coating. You can get RA flux (rosin, activated) in solder or in a bottle. It cleans off oxidized leads very well. Kester 44 solder is RA, and you can get the same stuff as Kester 1544 (only in gallons or pails unfortunately). However, MG Chemicals 835 RA flux is available from Digikey or Amazon in much smaller quantities for about 10 bucks. I use a small bottle with a stainless steel needle. When the needle clogs up (as it will), just touch it with the iron and it magically clears out. Cheers Phil Hobbs Dr. Hobbs: Thank you very much for your insight, sir! It's greatly appreciated! -Matthew Just 'Phil' to colleagues. The fancy sig block is for SEO purposes. (It works great btw.) Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net |
#12
Posted to sci.electronics.repair
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Newbie Question: Filing Down Component Leads
On Fri, 19 Jun 2015 05:46:13 -0700 (PDT), Matthew Connor
wrote: Good morning, Jeff! Thank you so much for your insight. My counter is a Lionel CD V-700 Model 6b, manufacture date 1962. That's the same as what I have. Watch out for leaky D cell batteries. I nearly destroyed mine when Duracell's leaked. On one hand, I'm a little confused. You mentioned several times different variations of me having likely "trashed" my counter by doing what I did. At the very end however, when I asked if I had done any harm, you said, "No. They're fine. After all, the counter was probably designed to survive a nuclear attack." So I'm not quite sure that I'm understanding if what I did was bad or not. I would say it was a bad thing to tear it apart. You didn't mention if it was working before you attacked, so I question whether any of the work you've done was worthwhile or productive. If it was dirty, just clean the board. There's no reason to clean the component leads, or make it pretty unless you're installing a clear case and using it for show and tell. The detrimental parts a 1. The phenolic PCB is very sensitive to handling, soldering, and "cleaning". You could easily have ruined it. 2. The coatings that you removed are there to prevent the high voltage power supply from being shorted by water condensation and high humidity. By removing the coating (probably some type of conformal coating), you have removed that protection. However, not all C V-700-6b counters had coated PCB's. One of mine does, while the other does not. 3. Some of the old components are difficult to find, such as the neon regulator tube, but are at least available. Unsoldering these and is a bit of a risk. http://www.surplustuff.com/radiolog.htm 4. The rotary switch is a big of a reliability problem. If you bend the contacts more than once, they'll break. The good news is that the device is very simple and has few components. It's made for easy repair, which is fairly easy. That's the origin of my bad joke about the counter surviving a nuclear attack. Drivel: It's not really a counter, because it doesn't count, but I can't get out of the habit of calling it a counter. On the other hand, you have given me lots of details to consider and suggestions in areas I haven't even started to think about. You've obviously got a great deal of experience and I'll be taking all of your suggestions into account as I move forward with my project. I'll be trying the breath moisture thing right away. Thanks for taking the time to educate an east coast newbie! -Matthew The breath test is fairly simple and will usually indicate immediately if you have a problem. I haven't tried it on mine for a long time, but as I recall, one counter consistently failed when I took it out a cold garage, and brought it into a warm house. With moisture all over the counter, it didn't work until it warmed up. This is a rather severe test and I would not expect even a conformally coated PCB to survive a condensed moisture test. However, a simple breath test should give you a clue as to how sensitive the counter is to moisture. If you want to fix that, some wax based conformal coating around where the GM tube cable connects to the PCB should be a good start. The wax coatings are nice because they come off easily if you need to do some rework. Make sure the PCB is clean and degreased before coating or you will trap the moisture under the wax. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#13
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Newbie Question: Filing Down Component Leads
On Thursday, June 18, 2015 at 1:53:09 PM UTC-4, Phil Hobbs wrote:
On 06/18/2015 10:16 AM, wrote: I've had old copper wires (In some old insulation.. zip cord type stuff) and it gets and oxide/ coating/ something/ that flux doesn't attack very well. I end up having to first scrap it with sand paper or a green scrubbie. (Scotch brite) and then tin it. I've always wondered what the tenacious oxide is. George H. I don't know. It seems to be some sort of organic crud iirc. I'm not sure if you're talking about the same stuff, but the organic crud I've encountered on old wires I've interpreted as being plasticizer from the PVC insulation -- the same sort of stuff that coats the insides of car windshields in the summer. -- Norman Yarvin http://yarchive.net/blog |
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