marxman6

Getting the metaI shield off is the worse bit ,it is in two parts, I left it off until the fix was well proven . I would NOT remove the caps , just systematicly reflow each leg of all components in the vicinity, make sure you use liquid "no clean" flux and a nice needle point iron, hot air is too hit and miss. If you want to replace any surface mount can caps (no need) twist them with pliers and they snap off niceley ,do not attempt to desolder as the solder pads will be damaged or rip off the board. I think the cause of the fault is that it is easy for input jack plug put direct leverage stress on the board with use and abuse, maybe 90degree jacks plugs would stop this in future. Good luck ,let us know how you get on .

Hi all, I just fixed my hd300 with these symptoms definitively, as has previously been mentioned and shown in these great photos ,the problem is very close to D3 under the metal input jack shield . I Repaced the 4x 10uf caps and thought all was well but after a week the same problem occured again .There were too many false positives .Eventually I got some freeze it spray and after shielding areas with kapton tape and cooling and reheating components one by one I got it to cycle the exact fault .even under the microscope all looked ok I resoldered with liquid flux all the U8(072 op amp) and D3 legs and straight away all was well even after freezing and heating again . So it was a thermal expansion fracture of solder legs problem No new parts needed! Thanks to ALL here that made this fix possible , Great community. and Good luck to the next person who finds this thread