Cell Phone -- What remains wet?
I am attempting to rescue my LG cell phone which spent about 15 minutes in
about six feet of water in a fresh water lake. I took it apart, dried everything out, and everything now works except the battery discharges much more rapidly even when the cell phone is OFF. This is not the same battery that was in the lake. Could it be the circuit board itself that is still wet, and if so, will it ever dry out? Dan |
Cell Phone -- What remains wet?
"Dan Dubosky" wrote in message ... I am attempting to rescue my LG cell phone which spent about 15 minutes in about six feet of water in a fresh water lake. I took it apart, dried everything out, and everything now works except the battery discharges much more rapidly even when the cell phone is OFF. This is not the same battery that was in the lake. Could it be the circuit board itself that is still wet, and if so, will it ever dry out? There is a conductive residue. A thorough washing with de-ionized water is usually required. |
Cell Phone -- What remains wet?
Charles wrote:
"Dan Dubosky" wrote in message ... I am attempting to rescue my LG cell phone which spent about 15 minutes in about six feet of water in a fresh water lake. I took it apart, dried everything out, and everything now works except the battery discharges much more rapidly even when the cell phone is OFF. This is not the same battery that was in the lake. Could it be the circuit board itself that is still wet, and if so, will it ever dry out? There is a conductive residue. A thorough washing with de-ionized water is usually required. ^ | | disassembly and proper PCB Michael |
Cell Phone -- What remains wet?
"msg" wrote in message ernet... Charles wrote: "Dan Dubosky" wrote in message ... I am attempting to rescue my LG cell phone which spent about 15 minutes in about six feet of water in a fresh water lake. I took it apart, dried everything out, and everything now works except the battery discharges much more rapidly even when the cell phone is OFF. This is not the same battery that was in the lake. Could it be the circuit board itself that is still wet, and if so, will it ever dry out? There is a conductive residue. A thorough washing with de-ionized water is usually required. ^ | | disassembly and proper PCB He said he took it apart ... |
Cell Phone -- What remains wet?
There is a conductive residue. A thorough washing with
de-ionized water is usually required. Actually, de-ionized water isn't de-ionized. It actually has "hard" ions replaced with "soft" ions. I'm old enough to remember the Wantz "Kleensteam" ion-exchage-resin column to make soft water for steam irons. |
Cell Phone -- What remains wet?
"William Sommerwerck" wrote in message . .. There is a conductive residue. A thorough washing with de-ionized water is usually required. Actually, de-ionized water isn't de-ionized. It actually has "hard" ions replaced with "soft" ions. Uncharged organic molecules, viruses, or bacteria left behind (after deionization) will not drain the cell-phone battery. |
Cell Phone -- What remains wet?
On Jun 18, 6:42*pm, "Charles" wrote:
"William Sommerwerck" wrote in message . .. There is a conductive residue. A thorough washing with de-ionized water is usually required. Actually, de-ionized water isn't de-ionized. It actually has "hard" ions replaced with "soft" ions. Uncharged organic molecules, viruses, or bacteria left behind (after deionization) will not drain the cell-phone battery. If it is a different battery, maybe the different battery is not as good as the original battery, I would take the phone and use alcohol to rinse it out. |
Cell Phone -- What remains wet?
"William Sommerwerck" wrote in message
. .. There is a conductive residue. A thorough washing with de-ionized water is usually required. Actually, de-ionized water isn't de-ionized. It actually has "hard" ions replaced with "soft" ions. Uncharged organic molecules, viruses, or bacteria left behind (after deionization) will not drain the cell-phone battery. Please read what I wrote, and do a little research under "ion-exchange" columns. Thank you. |
Cell Phone -- What remains wet?
"William Sommerwerck" wrote in message . .. There is a conductive residue. A thorough washing with de-ionized water is usually required. Actually, de-ionized water isn't de-ionized. It actually has "hard" ions replaced with "soft" ions. I'm old enough to remember the Wantz "Kleensteam" ion-exchage-resin column to make soft water for steam irons. I'm old enough to remember my mum using the melt water from defrosting the fridge. Gareth. |
Cell Phone -- What remains wet?
In article , "Dan Dubosky" wrote:
I am attempting to rescue my LG cell phone which spent about 15 minutes in about six feet of water in a fresh water lake. I took it apart, dried everything out, and everything now works except the battery discharges much more rapidly even when the cell phone is OFF. This is not the same battery that was in the lake. Could it be the circuit board itself that is still wet, and if so, will it ever dry out? I spent a combined effort of several hours first trying to dry the phone. I did that successfully before, not this time. Although dring it under a lamp and also using a desicant improved it greatly. I finally had the phone apart several times carefully cleaning, scraping, and also using some Bullfrog contact cleaner. After a week the phone seemed to go into a mode and say the battery was low, but would sometimes come back without shutting down. After a longer period the owner now reports its OK. ?? greg |
Cell Phone -- What remains wet?
Thanks to all who have contributed to this thread. I have benefited from
all of the remarks. I must admit I wasn't thinking of residual mineral or other type of deposits. When dry I thought that these would be in the order of megohms and since the cell phone works at such a low voltage, they would not matter. Everything that I had around, distilled water and alcohol, had measurable conductivity. I even measured some vodka. It too had measurable conductivity, but after properly disposing of it, I didn't care as much. So today I bought some Electronic Cleaner at my local Radio Shack. It comes with a brush to clean the printed circuit board. By tomorrow I should know whether I accomplished anything. Thanks to all again, Dan "GregS" wrote in message ... In article , "Dan Dubosky" wrote: I am attempting to rescue my LG cell phone which spent about 15 minutes in about six feet of water in a fresh water lake. I took it apart, dried everything out, and everything now works except the battery discharges much more rapidly even when the cell phone is OFF. This is not the same battery that was in the lake. Could it be the circuit board itself that is still wet, and if so, will it ever dry out? I spent a combined effort of several hours first trying to dry the phone. I did that successfully before, not this time. Although dring it under a lamp and also using a desicant improved it greatly. I finally had the phone apart several times carefully cleaning, scraping, and also using some Bullfrog contact cleaner. After a week the phone seemed to go into a mode and say the battery was low, but would sometimes come back without shutting down. After a longer period the owner now reports its OK. ?? greg |
Cell Phone -- What remains wet?
On Thu, 19 Jun 2008 16:25:45 -0400, Dan Dubosky wrote:
Everything that I had around, distilled water and alcohol, had measurable conductivity. I even measured some vodka. It too had measurable conductivity, but after properly disposing of it, I didn't care as much. LOL!! |
Cell Phone -- What remains wet?
"Dan Dubosky" wrote in message ... Thanks to all who have contributed to this thread. I have benefited from all of the remarks. I must admit I wasn't thinking of residual mineral or other type of deposits. When dry I thought that these would be in the order of megohms and since the cell phone works at such a low voltage, they would not matter. Everything that I had around, distilled water and alcohol, had measurable conductivity. I even measured some vodka. It too had measurable conductivity, but after properly disposing of it, I didn't care as much. So today I bought some Electronic Cleaner at my local Radio Shack. It comes with a brush to clean the printed circuit board. By tomorrow I should know whether I accomplished anything. Thanks to all again, Dan In general, the first rule with any kind of liquid damage, is get the battery out as fast as possible. I have on many occasions seen the results of electrolytic action across close spaced tracks and component legs, as a result of small currents passing through the liquid that is doing the contaminating. This often leaves a conductive 'corrosion' mess behind it, that can be quite difficult to remove, and tends to leave component legs and solder joints, a dull grey. Solder thus affected, is very difficult to reflow. Thru' plated holes can also be attacked, and if it gets that far, you are in trouble ... The areas usually worst affected, are those where the voltages and current availabilities, are highest i.e. around the power supply, so that may well go along with your apparent battery discharge problems. The second most important rule with liquid damage, is to get the item into a warm dry place as soon as possible, for at least 24 hours, before putting the battery back in. In the UK, that usually means the airing cupboard, where the household hot water storage cylinder is located. I've no idea whether houses in other countries have a similar cupboard, where bed linen is kept, for instance. Following these two 'rules', will often result in full recovery of the item, with no ongoing problems. Arfa |
Cell Phone -- What remains wet?
On Thu, 19 Jun 2008 16:25:45 -0400, Dan Dubosky wrote:
When dry I thought that these would be in the order of megohms and since the cell phone works at such a low voltage, they would not matter. Well, it also operates at _MEGA_ cycles -- where all sort of 'stuff' matters. |
Cell Phone -- What remains wet?
As I said previously, the phone operates perfectly except for a more rapid
discharge of the battery even when it is turned OFF. Of course, I have no idea what circuits are active under these circumstances to detect a request to turn the phone ON. If this is a small computer chip of some sort, I can see that you may be talking about Megacycles. That seems like overkill for a simple turn-on circuit, but I without a schematic diagram, I have no idea. Dan "Allodoxaphobia" wrote in message ... On Thu, 19 Jun 2008 16:25:45 -0400, Dan Dubosky wrote: When dry I thought that these would be in the order of megohms and since the cell phone works at such a low voltage, they would not matter. Well, it also operates at _MEGA_ cycles -- where all sort of 'stuff' matters. |
Cell Phone -- What remains wet?
"Arfa Daily" wrote in message ... In general, the first rule with any kind of liquid damage, is get the battery out as fast as possible. I have on many occasions seen the results of electrolytic action across close spaced tracks and component legs, as a result of small currents passing through the liquid that is doing the contaminating. This often leaves a conductive 'corrosion' mess behind it, that can be quite difficult to remove, and tends to leave component legs and solder joints, a dull grey. Thank you Arfa for an explanation of the possible mechanism involved in the creation of a conductive "corrosion" mess which may have remained even after I dried the cell phone out. The phone was in about six feet of water for about 15 minutes. It was not ON, but the battery was in place and I suspect that corrosive paths were established during that period of time. I don't remember enough electrochemistry to know exactly what was happening, but the lake water which I measured today does have measurable conductivity. It's actually about half the conductivity of my tap water which comes from a well so I guess I was better off dropping it in the lake than dropping it in my sink. :-) Dan |
Cell Phone -- What remains wet?
propman wrote:
On Thu, 19 Jun 2008 16:25:45 -0400, Dan Dubosky wrote: Everything that I had around, distilled water and alcohol, had measurable conductivity. I even measured some vodka. It too had measurable conductivity, but after properly disposing of it, I didn't care as much. LOL!! Hi Dan. The alcohol must be pure alcohol and not contain any water. Pure alcohol is not easy to get. Years ago at my place of employment we hsd some electronic equipment that had gone under water in a flood and what got the water out was pure alcohol which I believe has a great affinity for water. Had to get a clearance from the Customs and Excise people before getting a large bottle from a chemical supply company. The pure alcohol is very volatile and should be used very carefully, no smoking Lionel L Sharp |
Cell Phone -- What remains wet?
"William Sommerwerck" wrote in
: "William Sommerwerck" wrote in message . .. There is a conductive residue. A thorough washing with de-ionized water is usually required. Actually, de-ionized water isn't de-ionized. It actually has "hard" ions replaced with "soft" ions. Uncharged organic molecules, viruses, or bacteria left behind (after deionization) will not drain the cell-phone battery. Please read what I wrote, and do a little research under "ion-exchange" columns. Thank you. You are thinking of water softener columns. They replace hard ions with soft ones. Deionized water's quality is measured by checking the electrical conductivity of the water. Deionized water has low conductivity. In a de-ionizer, the ion exchange resin replaces Ca++, K+, Na+, etc with H+ The ion exchange resin replaces SO2--, CO3--, etc with OH- De ionized water thus has low conductivity. Softened water, on the other hand, is still conductive. -- bz 73 de N5BZ k please pardon my infinite ignorance, the set-of-things-I-do-not-know is an infinite set. remove ch100-5 to avoid spam trap |
Cell Phone -- What remains wet?
"William Sommerwerck" wrote in
: "William Sommerwerck" wrote in message . .. There is a conductive residue. A thorough washing with de-ionized water is usually required. Actually, de-ionized water isn't de-ionized. It actually has "hard" ions replaced with "soft" ions. Uncharged organic molecules, viruses, or bacteria left behind (after deionization) will not drain the cell-phone battery. Please read what I wrote, and do a little research under "ion-exchange" columns. Thank you. You are thinking of water softener columns. They replace hard ions with soft ones. Deionized water has low conductivity. http://www.veoliawaterst.com/en/files/?file=960 -- bz 73 de N5BZ k please pardon my infinite ignorance, the set-of-things-I-do-not-know is an infinite set. remove ch100-5 to avoid spam trap |
Cell Phone -- What remains wet?
I have now gone through a second cleaning with the Radio Shack Electronics
Cleaner. On the first round, I sprayed, lightly brushed, and sprayed again, and didn't really notice any discernable change in the rate of discharge. I guess I envisioned that the solution would dissolve the contaminated residue without a great deal of brushing. On the second round, I sprayed, more vigorously brushed, and sprayed again. After this I did see an improvement. It is probably not 100% cured, but I think that I am going to live with it as is. I'm afraid that during one of these sessions, I may create another problem that I didn't have before. In addition, perhaps the remaining conductive residues will dissipate with time. Yeh right --- well it's nice to have hope. Again, thanks to all. Dan "Dan Dubosky" wrote in message ... I am attempting to rescue my LG cell phone which spent about 15 minutes in about six feet of water in a fresh water lake. I took it apart, dried everything out, and everything now works except the battery discharges much more rapidly even when the cell phone is OFF. This is not the same battery that was in the lake. Could it be the circuit board itself that is still wet, and if so, will it ever dry out? Dan |
Cell Phone -- What remains wet?
In article , Lionel Sharp wrote:
propman wrote: On Thu, 19 Jun 2008 16:25:45 -0400, Dan Dubosky wrote: Everything that I had around, distilled water and alcohol, had measurable conductivity. I even measured some vodka. It too had measurable conductivity, but after properly disposing of it, I didn't care as much. LOL!! Hi Dan. The alcohol must be pure alcohol and not contain any water. Pure alcohol is not easy to get. Years ago at my place of employment we hsd some electronic equipment that had gone under water in a flood and what got the water out was pure alcohol which I believe has a great affinity for water. Had to get a clearance from the Customs and Excise people before getting a large bottle from a chemical supply company. The pure alcohol is very volatile and should be used very carefully, no smoking Lionel L Sharp If you apply pure alcohol to something, here comes the water. Water is best for disolving green stuff on terminals or traces. I have seen other colored material some times. My usual procedure for nasty equipment, water, alcohol, warm air blowing, sometimes add WD-40 or CRC 2-26, more blowing and drying. greg |
Cell Phone -- What remains wet?
This is a postscript to my previous messages. In an effort to clearly
determine whether a continued wetness or a corrosive residue was the problem in my cell phone's behavior, I conducted an experiment which seems to rule out a corrosive residue on the surface of the board. I cut out a small section of a circuit board which had two adjacent traces and measured the resistance between them. It measured as an open circuit on a meter that can measure tens of megohms. I then immersed the circuit board in water which I took from the lake in which my cell phone had spent about 15 minutes of time. The resistance measured between 22K to 28K Ohms. I then applied 3.7 volts to the terminals of the circuit board for 15 minutes. Immeditaely after removing the voltage, the resistance measured an open circuit but continued to drop rapidly until it reached the previous value in the 20K ohm range. I then dried the circuit board, and in a very short period of time, the measured resistance was again an open circuit. In other words, there did not appear to be any evidence of a corrosive residue on the surface of the board. I should say that I did not use the same circuit board that is in the cell phone. Perhaps the cell phone board is more porous and retained more of the water with impurities. In addition, I took the water for the experiment from the surface of the lake and not from the bottom, and the cell phone board was subjected to a higher water pressure at a six foot depth. Nevertheless, if I had to guess, I would say that pure alcohol as suggested by some in this thead would probably have done the most good in correcting the condition, and may in fact even improve the present state of the cell phone if I could ever find some. The circuit board may in fact still be wet to a small degree. It does not appear that the problem was a surface corrosive residue produce by the battery voltage being applied to the cell phone during its submersion. |
Cell Phone -- What remains wet?
Dan Dubosky wrote:
This is a postscript to my previous messages. In an effort to clearly determine whether a continued wetness or a corrosive residue was the problem in my cell phone's behavior, I conducted an experiment which seems to rule out a corrosive residue on the surface of the board. I cut out a small section of a circuit board which had two adjacent traces and measured the resistance between them. It measured as an open circuit on a meter that can measure tens of megohms. I then immersed the circuit board in water which I took from the lake in which my cell phone had spent about 15 minutes of time. The resistance measured between 22K to 28K Ohms. I then applied 3.7 volts to the terminals of the circuit board for 15 minutes. Immeditaely after removing the voltage, the resistance measured an open circuit but continued to drop rapidly until it reached the previous value in the 20K ohm range. I then dried the circuit board, and in a very short period of time, the measured resistance was again an open circuit. In other words, there did not appear to be any evidence of a corrosive residue on the surface of the board. I should say that I did not use the same circuit board that is in the cell phone. Perhaps the cell phone board is more porous and retained more of the water with impurities. In addition, I took the water for the experiment from the surface of the lake and not from the bottom, and the cell phone board was subjected to a higher water pressure at a six foot depth. Nevertheless, if I had to guess, I would say that pure alcohol as suggested by some in this thead would probably have done the most good in correcting the condition, and may in fact even improve the present state of the cell phone if I could ever find some. The circuit board may in fact still be wet to a small degree. It does not appear that the problem was a surface corrosive residue produce by the battery voltage being applied to the cell phone during its submersion. It's not just the water. it's the other stuff that's already on the board. Flux residue, electrolyte leaking out of caps, glues used in the assembly process. Whether or not the final inspector belched on it, Whether the cat peed on or near it. I'm gonna go out on a limb and suggest that water is never the problem. It's what is in the water that causes the grief. Water just ionizes it and makes it mobile. -- Return address is VALID! Bunch-O-Stuff Forsale He http://nm7u.tripod.com/homepage/sale.html |
Cell Phone -- What remains wet?
"mike" wrote in message news:tUg8k.29$od.22@trnddc07... It's not just the water. it's the other stuff that's already on the board. Flux residue, electrolyte leaking out of caps, glues used in the assembly process. Whether or not the final inspector belched on it, Whether the cat peed on or near it. I'm gonna go out on a limb and suggest that water is never the problem. It's what is in the water that causes the grief. Water just ionizes it and makes it mobile. -- Good point, Mike. There may have been something on the cell phone board that was not on my experimental board. I did however scrub the cell phone board twice with Radio Shack Electronics Cleaner and I think that there is still some effects left from the submersion. I only did the experiment since I thought that some were suggesting that there was some corrosive residue created by the material in the less than pure water, but they may in fact have been referring to residue materials of the type that you have suggested. |
Cell Phone -- What remains wet?
On Tue, 24 Jun 2008 21:28:04 -0400 "Dan Dubosky"
wrote: Good point, Mike. There may have been something on the cell phone board that was not on my experimental board. I did however scrub the cell phone board twice with Radio Shack Electronics Cleaner and I think that there is still some effects left from the submersion. It sounds like you've been careful and thorough, but your board might benefit from additional scrubbings in some other solvents, since not everything is soluble in Radio Shack Electronics Cleaner. In general, I clean things by starting with clean water, since it is the most universal solvent. If it is really dirty, I may start with soap and water and a toothbrush. Then I follow up with clean water, then distilled water, and finally alcohol, and I don't worry about the fact that it isn't 100% alcohol. The purpose of the alcohol is to carry off as much of the water as possible, so that it can't dry in place and leave any residue. A side benefit is that the water that's in the alcohol will be extremely pure. Of course the residue will be minimized by the sequence of rinses above, but you can't always control what comes off the board. If possible, use compressed air to blow the board off, thus minimizing remaining fluid which will leave a residue when it drys in place. And finally, you probably can't do any of this if your board includes assemblies that water, etc, can get into but not easily back out. This includes things like switches, pots, and transformers. And then, of course, you have to thoroughly dry the board. I have a friend who tells of starting his cleaning process by running his boards thru the wash cycle of his kitchen dishwasher, with soap. - ----------------------------------------------- Jim Adney Madison, WI 53711 USA ----------------------------------------------- |
Cell Phone -- What remains wet?
In article ,
Jim Adney wrote: I have a friend who tells of starting his cleaning process by running his boards thru the wash cycle of his kitchen dishwasher, with soap. Bob Pease swears by this process. He writes (in "Troubleshooting Analog Circuits", a book I most strongly recommend) that when he's working on PC-board circuits which require low leakage currents, he'll run 'em through the dishwasher, standard cycle, using a normal load of Calgonite detergent. When the wash and rinse are complete, he takes them out, raps/shakes/blows off the rinse water, and stacks them in the dishstrainer to dry. He says that this process results in lower board-leakage currents than the more traditional PC-board cleaning processes which use organic solvents. I believe that the use of Calgonite is significant - I looked it up and found that it contains surfactants and calcium metasilicate, and is significantly alkaline, but it does not contain chlorine. Other powdered dish detergents (e.g. Cascade) do contain chlorine, and I suspect that they might corrode components on a circuit board. -- Dave Platt AE6EO Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
Cell Phone -- What remains wet?
"Dan Dubosky" wrote in
: "mike" wrote in message news:tUg8k.29$od.22@trnddc07... It's not just the water. it's the other stuff that's already on the board. Flux residue, electrolyte leaking out of caps, glues used in the assembly process. Whether or not the final inspector belched on it, Whether the cat peed on or near it. I'm gonna go out on a limb and suggest that water is never the problem. It's what is in the water that causes the grief. Water just ionizes it and makes it mobile. -- Good point, Mike. There may have been something on the cell phone board that was not on my experimental board. I did however scrub the cell phone board twice with Radio Shack Electronics Cleaner and I think that there is still some effects left from the submersion. I only did the experiment since I thought that some were suggesting that there was some corrosive residue created by the material in the less than pure water, but they may in fact have been referring to residue materials of the type that you have suggested. It is likely that some SMT components or other components still have conductive residue between the part and the board. I 'repaired' a laptop computer that had 'merlott' [wine] spilled in it. It was left powered on over the weekend. The repair consisted of remove power sources disassembly Rinse with plenty of clean water rinse with alcohol scrubbing and scraping to remove visible conductive paths. rinse that area with water and alcohol. rebuilding a couple of conductors that had been eaten away completely drying. Many hours of sitting in the flow of warm, dry air from an air vent. The keyboard took a long time to dry. reassembly. -- bz 73 de N5BZ k please pardon my infinite ignorance, the set-of-things-I-do-not-know is an infinite set. remove ch100-5 to avoid spam trap |
Cell Phone -- What remains wet?
"bz" wrote in message . 139... "Dan Dubosky" wrote in : "mike" wrote in message news:tUg8k.29$od.22@trnddc07... It's not just the water. it's the other stuff that's already on the board. Flux residue, electrolyte leaking out of caps, glues used in the assembly process. Whether or not the final inspector belched on it, Whether the cat peed on or near it. I'm gonna go out on a limb and suggest that water is never the problem. It's what is in the water that causes the grief. Water just ionizes it and makes it mobile. -- Good point, Mike. There may have been something on the cell phone board that was not on my experimental board. I did however scrub the cell phone board twice with Radio Shack Electronics Cleaner and I think that there is still some effects left from the submersion. I only did the experiment since I thought that some were suggesting that there was some corrosive residue created by the material in the less than pure water, but they may in fact have been referring to residue materials of the type that you have suggested. It is likely that some SMT components or other components still have conductive residue between the part and the board. I 'repaired' a laptop computer that had 'merlott' [wine] spilled in it. It was left powered on over the weekend. The repair consisted of remove power sources disassembly Rinse with plenty of clean water rinse with alcohol scrubbing and scraping to remove visible conductive paths. rinse that area with water and alcohol. rebuilding a couple of conductors that had been eaten away completely drying. Many hours of sitting in the flow of warm, dry air from an air vent. The keyboard took a long time to dry. reassembly. -- bz 73 de N5BZ k There's a board that I repair commercially, that comes from an automatic drinks vending machine. Often, when I receive them, they are caked in ingredient residue that has been flying about inside the machine, which makes them pretty much impossible to work on, so the first thing they get is a wash. I just run the water until it's coming out of the sink tap (faucet for our U.S. colleagues ?) at its hottest, squirt a little ordinary washing up liquid on the board, flick some of the hot water on with a pan-scrubbing brush, and then work that up into a thick lather, scrubbing between the legs of the through-hole components. When it's had a good scrub, it gets run under that hot water stream, until all of the soap is off both sides. It then gets shaken, patted dry on a dish towel, before being stood vertically in front of an electric fan heater for about 5 minutes. The result of all of this is a board that looks like it has just come out of the factory, and I have never had any future problems with any residues, and I've been doing it to this particular job for about 6 years now. As well as through-hole components, this board also has many s.m. components on it, including both I.C.s and passives. It does not, however, have any 'closed in' components such as coils, IF transformers etc, which as someone else suggested, would probably not take kindly to being flooded with water ... Arfa |
Cell Phone -- What remains wet?
In article , Jim Adney wrote:
On Tue, 24 Jun 2008 21:28:04 -0400 "Dan Dubosky" wrote: Good point, Mike. There may have been something on the cell phone board that was not on my experimental board. I did however scrub the cell phone board twice with Radio Shack Electronics Cleaner and I think that there is still some effects left from the submersion. It sounds like you've been careful and thorough, but your board might benefit from additional scrubbings in some other solvents, since not everything is soluble in Radio Shack Electronics Cleaner. In general, I clean things by starting with clean water, since it is the most universal solvent. If it is really dirty, I may start with soap and water and a toothbrush. Then I follow up with clean water, then distilled water, and finally alcohol, and I don't worry about the fact that it isn't 100% alcohol. I have cleaned stubborn high impedance loading by using mostly alcohol and the Weller air pencil set to a high flow and low temperature. The problems were under the components. I sometimes have to repeat many times before all the flux and residue is out. You have to move the air pencil around under components, going mostly in one direction. The old boss made me use alcohol. By the way, the cell phone I worked with appears to be OK after much cleaning, cyclic baking, and a month delay. greg |
Cell Phone -- What remains wet?
On Wed, 25 Jun 2008 15:42:52 GMT (GregS)
wrote: I have cleaned stubborn high impedance loading by using mostly alcohol and the Weller air pencil set to a high flow and low temperature. The problems were under the components. I sometimes have to repeat many times before all the flux and residue is out. You have to move the air pencil around under components, going mostly in one direction. The old boss made me use alcohol. Rosin flux doesn't dissolve completely in either water or alcohol, but I've found that by alternating rinses, I can eventually remove it. In cases like that, it might pay to invest in commercial flux remover, if only to get things started. I'd still finish up with water and then alcohol, however. By the way, the cell phone I worked with appears to be OK after much cleaning, cyclic baking, and a month delay. In that case, there was probably something on the board that was just hard to get the water out of. The real test will be to see whether it continues to work in humid weather. That's when residue can resorb moisture and start causing problems again. If there's no residue, then humid weather should not cause any problems. - ----------------------------------------------- Jim Adney Madison, WI 53711 USA ----------------------------------------------- |
Cell Phone -- What remains wet?
"Dan Dubosky" wrote in message ... I have now gone through a second cleaning with the Radio Shack Electronics Cleaner. On the first round, I sprayed, lightly brushed, and sprayed again, and didn't really notice any discernable change in the rate of discharge. I guess I envisioned that the solution would dissolve the contaminated residue without a great deal of brushing. On the second round, I sprayed, more vigorously brushed, and sprayed again. After this I did see an improvement. It is probably not 100% cured, but I think that I am going to live with it as is. I'm afraid that during one of these sessions, I may create another problem that I didn't have before. In addition, perhaps the remaining conductive residues will dissipate with time. Yeh right --- well it's nice to have hope. Again, thanks to all. Dan Many thanks to all of you. The cell phone now appears to be back to normal. Yesterday, I purchased "denatured alcohol solvent" by a company called Sunnyside. It was in a well sealed can with a plastic top that had to be removed, and is said to contain denatured alcohol and less than 4% methanol. I don't know its purity, but when I stuck my finger in it and it got under my nail, it really burned. I completely bathed the main circuit board in this solvent for about one minute while brushing around the main side of the board. I then let it completely dry for over 30 minutes, first in the sun and then under an incandescent light. I charged the cell phone up last night, and this morning there is no significant discharge. The large SMT components have a sealant around their base but many of the smaller components do not have such a sealant. So moisture could easily have remained under them and within the many push button switches. Today is a very humid day so it will be interesting to see how much discharge occurs. Again, thanks to all. Dan |
Cell Phone -- What remains wet?
Jim Adney wrote in
: On Tue, 24 Jun 2008 21:50:46 -0700 (Dave Platt) wrote: In article , Jim Adney wrote: I have a friend who tells of starting his cleaning process by running his boards thru the wash cycle of his kitchen dishwasher, with soap. Bob Pease swears by this process. He writes (in "Troubleshooting Analog Circuits", a book I most strongly recommend) that when he's working on PC-board circuits which require low leakage currents, he'll run 'em through the dishwasher, standard cycle, using a normal load of Calgonite detergent. I have the book, and I read it years ago, but I'd forgotten that Bob also did this. - ----------------------------------------------- Jim Adney Madison, WI 53711 USA ----------------------------------------------- I used to use the auto dishwasher trick at the Orlando TEK field office,on 2236 DMM boards,cured many leakage problems.used Calgonite,BTW. And we had a drying oven that had a negative pressure inside. -- Jim Yanik jyanik at kua.net |
Cell Phone -- What remains wet?
Jim Yanik wrote:
snip I used to use the auto dishwasher trick at the Orlando TEK field office,on 2236 DMM boards,cured many leakage problems.used Calgonite,BTW. And we had a drying oven that had a negative pressure inside. The TEK field office in St. Paul used to clean 500 series gear amongst other things in a sort of dishwasher and also had the drying oven; was this equipment standardized amongst the field offices? Michael |
Cell Phone -- What remains wet?
msg wrote in
ernet: Jim Yanik wrote: snip I used to use the auto dishwasher trick at the Orlando TEK field office,on 2236 DMM boards,cured many leakage problems.used Calgonite,BTW. And we had a drying oven that had a negative pressure inside. The TEK field office in St. Paul used to clean 500 series gear amongst other things in a sort of dishwasher and also had the drying oven; was this equipment standardized amongst the field offices? Michael Heh,I washed down a lot of 500 series tube scopes! It made a big difference,too. well,everybody seems to have had different equipment for the task. I had to persuade the Orlando manager to ship the old wash/spray booth from the closed TEK-Indianapolis office,and their drying ovens were from different manufacturers.Some TEK field offices had NO wash/dry facilities. (moot point now;they're all closed.) I had to take boards home to run through MY dishwasher. I didn't know of any TEK offices that had a auto dishwasher. -- Jim Yanik jyanik at kua.net |
Cell Phone -- What remains wet?
Dave Platt wrote:
In article , Jim Adney wrote: I have a friend who tells of starting his cleaning process by running his boards thru the wash cycle of his kitchen dishwasher, with soap. Bob Pease swears by this process. He writes (in "Troubleshooting Analog Circuits", a book I most strongly recommend) that when he's working on PC-board circuits which require low leakage currents, he'll run 'em through the dishwasher, standard cycle, using a normal load of Calgonite detergent. When the wash and rinse are complete, he takes them out, raps/shakes/blows off the rinse water, and stacks them in the dishstrainer to dry. He says that this process results in lower board-leakage currents than the more traditional PC-board cleaning processes which use organic solvents. I believe that the use of Calgonite is significant - I looked it up and found that it contains surfactants and calcium metasilicate, and is significantly alkaline, but it does not contain chlorine. Other powdered dish detergents (e.g. Cascade) do contain chlorine, and I suspect that they might corrode components on a circuit board. I have to side with Bob Pease. Over the years of reading his column in Electronic Design, and stuff in NSC's data books, he has had tons of experience with analog and is usually dead on. He was behind the now classic 'Floobydust' data book back in 1977. Back then everything was washed in a freon solvent tank but times have changed, no more freon tanks, Lead is being banned, etc. I never dismiss his stuff as rambling since he almost always puts in a nugget or two. Bill Baka |
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