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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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PbF policy China and USA ?
Line 6 Spider 3 amp with RoHS and PbF markings all over, date only 2008, no
abusive use/speaker/lead problem. The boards are obviously PbF , white deposit as though been in a damp shed for 10 years. That is except for the interboard ribbon soldering. Boards populated and soldered in China with PbF solder and assembled in USA with leaded-solder or 2 flavours of PbF solder, one goes white easily and the other stays shiney? TDA7293 failed , going by burnt off lacquer on the minor trace between power - supply and signal - supply , then failure in signal half of the amp. Final failure was sub-ohm connection between +,- and output pin and about 40 ohm to ground. If there had been intermittant contact to a pin due to PBf , could that knock out a hybrid? Tugging on dropper Rs etc has not shown any so-elucidated poor joints on the rest of the board and no PbF part-ring cracks seen. |
#2
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PbF policy China and USA ?
Unlikely joint failure at the pins as they are set in ring-barb hank bushes.
Monolithic, not hybrid, I decided to crack this one open , not much to see other than smoke staining and strong smell of smoke. |
#3
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PbF policy China and USA ?
I reckon it was probably slack h/s clamp. Although not noticably loose on
undoing, there is no permanent deformation of the silipad on this one (unlike its companion TDA). Clamp is 3:1 ratio cantilever U section steel, ratio the wrong way and no star washer or equivalent under the retaining bolt heads |
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