How do American repairers get on with PbF boards, not marked as PbF. Is
there an overlay codification meaning PbF or LF ? Has anyone collated
together what USA makers + models for what 21C years definitely had PbF or
definitely had leaded solder? Or putting it another way , what is the
probability of any China manufacturer using leaded solder in 2001/ .../2007/
.... ?
This amp made in China in 2007, for USA, exported to UK. Balance of
probabilities from appearance, indentation test etc is probably PbF.
Yet again faced with repairing a "fully working" but intermittant failure
PbF amp
However much tugging and twisting on input and output and pot boards cannot
get either channel to fail, as user contact there, most likely failure
areas. Closely inspecting all boards - no bad-contact solder found. So far
powering to 75 percent mains, noting some mid-amp signal AC and DCs , as
nothing useful out there on this amp. Before upping the mains (may of course
cause a protect failure in one ch from that) . And before seriously
attacking the main amps with engraver tool and nylon bolt as tip ,
monitoring large dummy loads with attenuated phones, to try and make a
failure.