Hello! I bought a sony wm f75 sports a bit ago and it ended up being one of those projects were once you fix one thing another thing breaks. I had finally gotten it to a point were it would've worked but it stopped powering on from the positive battery wire coming off, But after re soldering it I find that it will power on for a few seconds, then power off and the battery contacts will get really hot ( to the point were if I don't take them out within 10 seconds the plastic starts to melt), If I re flow the solder it will power on again but then repeat that process. Any advice? Thanks.
From your description, it sounds as if you have a catastrophic short circuit which is resulting in very high power consumption and overheating. This could be due to a mechanical short such as a solder bridge on the tracks or a loose wire touching a part of the circuit which it shouldn't, or you could have a component failure. In the latter case it is likely that one component has failed and then damaged others in the circuit. While you have the walkman powered up from the batteries, it is likely that more damage is being done as there is no current limiting other than the internal resistance of the batteries. From your post it appears that you do not have much experience of fault finding or repairing electronic circuits therefore you need to seek the help of a technician who has the knowledge and equipment to be able to repair it. In the meantime, take the batteries out and do not power the walkman up again as you will only cause further damage by doing so.
