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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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Pick and Place damage ?
4 year old board covered in low power SMD.
Intermittant noise problem located to one 1206 format 3K9 resistor. No solder problem , but resistor would appear to be cracked in its body, can't see anything under 30x microscope, but measuring over the lands , can be stressed towards o/c. Not yet removed it as a more urgent job begs. How do you stress all such 1206 devices , safely, to check if there are others similar, without causing the damage being sought? -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ |
#2
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Pick and Place damage ?
On 3ÔÂ11ÈÕ, ÏÂÎç11ʱ49·Ö, "N Cook" wrote:
4 year old board covered in low power SMD. Intermittant noise problem located to one 1206 format 3K9 resistor. No solder problem , but resistor would appear to be cracked in its body, can't see anything under 30x microscope, but measuring over the lands , can be stressed towards o/c. Not yet removed it as a more urgent job begs. How do you stress all such 1206 devices , safely, to check if there are others similar, without causing the damage being sought? -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list onhttp://home..graffiti.net/diverse:graffiti.net/ Do you want access to China's massive pool of electronic manufacturers... but lack the time to contact suppliers, negotiate contracts, arrange shipping or monitor product quality? Don't worry - Let seriouswholesale deal with all that for you. *Check out the huge range of Gadgets, MP3 / MP4 Players, Car DVD / Audio, and Computer Accessories now by visiting the online wholesale catalog at seriouswholesale. com You'll have peace of mind thanks to the seriouswholesale Quality Control, 12-month Warranty on all products, and easy secure payment by credit card through Paypal. Selling on eBay or your own online store? Send products direct from our warehouse to your customers using our unique drop-shipping service. You can profit by selling hundreds of different products, without holding any of your own inventory! Any questions you have will be answered by the seriouswholesale English-speaking customer support team... Their aim is to make your China electronics importing business easier to run than ever before. Welcome to http://www.seriouswholesale.com. seriouswholesale - Buy from the source, profit without the hassle. - 12 Months Warranty - No minimum order restrictions - Drop-shipping with no additional fee - Pay by safely by PayPal seriouswholesale Wholesale Co., Ltd.: Chinas original and best online electronics wholesaler & drop-shipper: seriouswholesale. com |
#3
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Pick and Place damage ?
In article ,
"N Cook" wrote: 4 year old board covered in low power SMD. Intermittant noise problem located to one 1206 format 3K9 resistor. No solder problem , but resistor would appear to be cracked in its body, can't see anything under 30x microscope, but measuring over the lands , can be stressed towards o/c. Not yet removed it as a more urgent job begs. How do you stress all such 1206 devices , safely, to check if there are others similar, without causing the damage being sought? -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ Did you reflow the solder yet? Even at 30x, a crack could escape one's notice. If the board was panelized and the suspect resistor is near the edge, depaneling may have stressed it and/or the solder that holds it. |
#4
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Pick and Place damage ?
Smitty Two wrote in message
news In article , "N Cook" wrote: 4 year old board covered in low power SMD. Intermittant noise problem located to one 1206 format 3K9 resistor. No solder problem , but resistor would appear to be cracked in its body, can't see anything under 30x microscope, but measuring over the lands , can be stressed towards o/c. Not yet removed it as a more urgent job begs. How do you stress all such 1206 devices , safely, to check if there are others similar, without causing the damage being sought? -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ Did you reflow the solder yet? Even at 30x, a crack could escape one's notice. If the board was panelized and the suspect resistor is near the edge, depaneling may have stressed it and/or the solder that holds it. In main body of board , not been dropped or abused in use I desoldered it and it is failure of the bond between the resistive film and one of the lands but no crack in the body in the sense that it holds together in normal handling. I have a small adjustable automatic centre punch (spring loaded ratchet release for easy centre popping of sheet metal). The minimum imulse setting of that is 9Kg but found a couple of much weaker springs to try inside . one gives range 1.5 to 2 Kg before the impulse, the other 2.5 to 3Kg range of adjustment. I was thinking of pinging at the 1.5Kg setting on all the 3K9 SM Rs on the board after DVM checking and then DVM after pinging. Any opinions ? Probably about 6 to 10 of that value on the board -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ |
#5
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Pick and Place damage ?
In article ,
"N Cook" wrote: Smitty Two wrote in message news In article , "N Cook" wrote: 4 year old board covered in low power SMD. Intermittant noise problem located to one 1206 format 3K9 resistor. No solder problem , but resistor would appear to be cracked in its body, can't see anything under 30x microscope, but measuring over the lands , can be stressed towards o/c. Not yet removed it as a more urgent job begs. How do you stress all such 1206 devices , safely, to check if there are others similar, without causing the damage being sought? -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ Did you reflow the solder yet? Even at 30x, a crack could escape one's notice. If the board was panelized and the suspect resistor is near the edge, depaneling may have stressed it and/or the solder that holds it. In main body of board , not been dropped or abused in use I desoldered it and it is failure of the bond between the resistive film and one of the lands but no crack in the body in the sense that it holds together in normal handling. I have a small adjustable automatic centre punch (spring loaded ratchet release for easy centre popping of sheet metal). The minimum imulse setting of that is 9Kg but found a couple of much weaker springs to try inside . one gives range 1.5 to 2 Kg before the impulse, the other 2.5 to 3Kg range of adjustment. I was thinking of pinging at the 1.5Kg setting on all the 3K9 SM Rs on the board after DVM checking and then DVM after pinging. Any opinions ? Probably about 6 to 10 of that value on the board If your objective is to test "without causing the damage being sought," I personally wouldn't use the center punch. Maybe a light tap from the butt end of a dental probe. I know you enjoy the intellectual exercise in these matters, but if you're really wary of the other resistors, why not just replace them all since there's only a handful? |
#6
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Pick and Place damage ?
Smitty Two wrote in message
news In article , "N Cook" wrote: Smitty Two wrote in message news In article , "N Cook" wrote: 4 year old board covered in low power SMD. Intermittant noise problem located to one 1206 format 3K9 resistor. No solder problem , but resistor would appear to be cracked in its body, can't see anything under 30x microscope, but measuring over the lands , can be stressed towards o/c. Not yet removed it as a more urgent job begs. How do you stress all such 1206 devices , safely, to check if there are others similar, without causing the damage being sought? -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ Did you reflow the solder yet? Even at 30x, a crack could escape one's notice. If the board was panelized and the suspect resistor is near the edge, depaneling may have stressed it and/or the solder that holds it. In main body of board , not been dropped or abused in use I desoldered it and it is failure of the bond between the resistive film and one of the lands but no crack in the body in the sense that it holds together in normal handling. I have a small adjustable automatic centre punch (spring loaded ratchet release for easy centre popping of sheet metal). The minimum imulse setting of that is 9Kg but found a couple of much weaker springs to try inside . one gives range 1.5 to 2 Kg before the impulse, the other 2.5 to 3Kg range of adjustment. I was thinking of pinging at the 1.5Kg setting on all the 3K9 SM Rs on the board after DVM checking and then DVM after pinging. Any opinions ? Probably about 6 to 10 of that value on the board If your objective is to test "without causing the damage being sought," I personally wouldn't use the center punch. Maybe a light tap from the butt end of a dental probe. I know you enjoy the intellectual exercise in these matters, but if you're really wary of the other resistors, why not just replace them all since there's only a handful? 1.5Kg sounds worse than it is. Trying on the back of my hand is not painful or self-mutillation. -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ |
#7
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Pick and Place damage ?
N Cook wrote:
1.5Kg sounds worse than it is. Trying on the back of my hand is not painful or self-mutillation. Your skin isn't brittle ceramic, either. -- Sig file? I don't need no steenkin sig file! |
#8
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Pick and Place damage ?
Michael A. Terrell wrote in message
... N Cook wrote: 1.5Kg sounds worse than it is. Trying on the back of my hand is not painful or self-mutillation. Your skin isn't brittle ceramic, either. -- Sig file? I don't need no steenkin sig file! Pinged, at 1.5Kg, the 7 Rs of that value, on the side rather than top as that messed up the printing. No resistance variation before or after but if it bounces back then I know what to check first. The owner could not believe how tiny the miscreant was, lost in a minigrip bag. -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ |
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